gec alang report (main document part i)

Ecological Restoration and Planning forAlang-Sosiya Ship-Breaking Yard, Gujarat

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INTRODUCTION

The emerging global concern for environmentalprotection, particularly for the sustainabledevelopment of human societies, is now beingechoed in all corners. Moreover, the concern todayis not limited to just the immediate and obviousbut transcends several other boundaries in time,space and perception.

The perception of the oceans being just globaldump yards is steadily being replaced by aviewpoint that considers them as integral featuresof the biosphere. Particular attention is also beinggiven to the crucial interface of the land and oceanbecause of its characteristic properties that areslowly being understood. These are also the areasfor intense commercial activities such asanchorages and recreation.

Ship-breaking is an activity that is presentlyconfined only to a few locales in the world.Consequently, few attempts have been made tounderstand the effects of this specialised type ofactivity, especially in terms of its effects on thespecific ecosystem functions.

Ship-breaking activity provides scrap salvage fromthe ships to a significant proportion of the scrapusers. Re-rollable and melting scrap is animportant raw material for several products of ironand steel industry. Ship-breaking is, thus,essentially based on recycling of resources. Evenif we leave aside - for the time being - thesignificance of this industry as an important sourceof raw material for steel products, its relevancefor conservation of natural resources need no over-emphasis.

1.1 GLOBAL SCENARIO OFSHIP-BREAKING

Though the origin of the idea of ship-breaking maybe traced to 'forced' ship-breaking undertaken bythe USA and the UK during the Second WorldWar, its recent growth is phenomenal and is largelythe result of conditions in the steel industry,

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availability of labour supply at competitive wagerates and policies of Governments of ship-breakingcountries, besides some most favourable naturalattributes available at specific sites countries forthe growth of ship-breaking.

It is significant to note that three important factorscaused flight of ship-breaking from the USA andthe UK in favour of less industrialised countrieslike Spain, Italy and Turkey during the sixties andseventies. They were:

l rise in wages for labour,

l increased global availability of steel scrapat competitive prices, and

l the issues raised by ecologists regardingpollutants contained in ships brought for breaking.

Similarly, Japan abandoned ship-breaking whenthe higher wage rates in Japan rendered thisactivity non-competitive as against the nearbycountries of Pacific Asia. Some of the East Asiancountries like Taiwan and South Korea couldimprove their share in ship-breaking, followingthe withdrawal of the USA, the UK and Japan,due to sufficiently low wage costs. Pakistan alsoentered into ship-breaking with an addedadvantage of natural beaching of ships alongGadani site, besides availabilities of workers thereat low wage rates. Later, Taiwan lost its share inthe global tonnage of ship-breaking with thedisappearance in 1983 of the cartel, whichTaiwanese ship-breakers had formed for buyingships at bargain rates.

South Korean ship-breakers' major attraction wasultra large and very large crude oil carriers [ULCCsand VLCCs]. But the availability of such vesselsgot drastically reduced during the eighties, whichmade South Korea disinterested in ship-breaking.It would be seen from the Table 1.1 and Table 1.2that, ultimately, India, Bangladesh, China andPakistan emerged as the four major ship-breakingcountries in the early nineties accounting foraround 92 percent of the total tonnage broken.


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TABLE 1.1Overall summary of gross tonnage broken by major ship-breaking countries(1990-1995)

Country 1990 1991 1992 1993 1994 1995

Bangladesh 0.2 0.5 1.2 1.4 2.1 2.5China 0.1 0.2 2.2 5.5 2.8 0.8India 1.1 0.8 2.0 1.9 2.8 2.8Pakistan 0.0 0.4 0.7 0.9 2.2 1.7

Sub-total 1.4 1.9 6.1 10.0 9.9 7.8

Other Countries 0.4 0.5 0.5 0.7 0.5 0.7

Total 1.8 2.4 6.6 10.7 10.4 8.5

TABLE 1.2Percentage share in the world total

Country 1990 1991 1992 1993 1994 1995

Bangladesh 11.11 20.83 18.18 13.08 20.19 29.41China 05.56 08.33 33.33 54.21 26.92 09.41India 61.11 33.33 30.30 27.75 26.92 32.94Pakistan - 16.67 10.61 08.41 21.15 20.00

Sub-total 77.78 79.17 92.42 93.45 95.19 91.76

Other Countries 22.22 20.83 07.58 06.54 04.81 08.24

Total 100.00 100.00 100.00 100.00 100.00 100.00

(Source: Lloyds Register Statistics)

l wage rates are competitively low inBangladesh;

l limited availability of getting steel throughthe alternative routes in that country and

l prices of ship-scrap in the domestic marketin Bangladesh is relatively high.

The above analysis suggests that ship-breakingactivity is greatly influenced by a number of factorswhich have made this industry prone to globallocational shifts. Starting from the USA, the UKand Japan, this industry changed its location infavour of Mediterranean region and then movedto East and South Asian Countries. The Industrypushed China to the top in the early nineties andimmediately thereafter reversed the situation.Factors affecting ship-breaking have given it a

Though China enjoyed the top-ranking positionin ship-breaking during the years 1992, 1993 and1994, the country lost its share drastically in 1995.China has found it possible now to produce cheapersteel through routes other than ship-breaking and,therefore, has reduced its ship-breaking activity.China being a centrally planned, totalitariancountry, could implement the sudden policychange.

It was believed earlier that when the limiteddemand for ship-scrap is satisfied in the domesticsteel markets of Bangladesh and Pakistan, Indiawould have to face competition in ship-breakingonly from the side of China. But now, when Chinais almost out of the picture, India is facingcompetition mostly from Bangladesh for threereasons, viz.,


roller-coaster characteristic, when its growth isexamined in the form of tonnage broken over time.The industry experienced fluctuation - not only ofthe roller-coaster type but also of the leap andcrawling type during the period of 1975-1995 (Fig1.1 and Table 1.3). This further suggests thatgrowth of ship-breaking cannot be left entirely to

market forces, if a country intends to continuereaping the gains typical of this industry.

1.2 THE INDIAN PERSPECTIVE

A sharp contrast between growth of ship-breakingin India vis-à-vis that of the world is evident from

TABLE 1.3:Gross tonnage broken in World and in India during 1975-1995

Year Global gross India's gross Percentage share oftonnage [MT.] tonnage [MT.] India in the world tonnage

1975 5.1 0.010 00.201976 6.6 0.047 00.711977 6.1 0.063 01.031978 10.1 0.013 00.131979 6.7 0.074 01.101980 6.0 0.090 01.501981 7.3 0.143 01.961982 13.6 0.313 02.301983 16.8 0.524 03.121984 17.8 0.460 02.581985 22.2 1.303 05.871986 20.3 0.636 03.131987 12.0 1.690 14.081988 5.0 0.462 09.241989 2.5 0.680 27.201990 1.8 1.092 60.671991 2.4 0.800 33.331992 6.6 2.000 30.301993 10.7 1.900 17.761994 10.4 2.800 26.921995 8.5 2.800 32.94

(Source: Lloyds Register Statistics and Kamdar 1997)

Fig 1.1 Gross tonnage of ship broken in the World and share of India

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Table 1.3 and Fig 1.1. When the global ship-breaking was doing exceedingly well during theperiod from 1982 through 1986, India was justcrawling. Whereas, during the subsequent periodafter 1987, when world ship-breaking lost itsmomentum, India took a quantum jump. This issuggestive of a very important fact that factorsaffecting growth of ship-breaking in India are notentirely the same which decided growth of thisIndustry elsewhere.

India has a vast and growing market for steel,particularly for the long steel and light structures- used mostly in the construction industry. Themost economical route for production of such itemsis through the re-rolling mills which demandsship-scrap as a raw material. The re-rolling sectorof India has accumulated high idle capacity whichallows this sector to immediately respond tochanges in market-demand for long products andlight structures.

The production of steel enjoys a cost-advantage inthe re-rolling sector as compared to the alternativeroutes- particularly on energy costs. For theproduction of steel in India, the closest competitorof the re-rolling sector is the Electric Arc Furnace[EAF] route which consumes more electricity andis burdened by high tariffs. Re-rolling mills utilisesteel-scrap salvaged from ship-breaking througha labour intensive process.

Ship-breaking being labour intensive and capitalsaving, uses relatively less amount of capital perunit of output. This tends to reduce interest costsin producing steel-scrap.

The production of steel scrap in ship-breaking doesnot use motive power - particularly electricity. Thisgives a clear advantage to India's ship-breakingindustry as electricity here has been suffering fromsevere supply side constraints.

There may be hardly any country in the world,except India, which is in a position to supply steelscrap and its products - particularly long steel andlight structures - with the highest cost advantagein the domestic market through concomitantdevelopment of ship-breaking and re-rollingsectors wherein cost-optimality is achieved throughthe lower wage, interest and energy costs.

The above analysis, however, does not answer the

following two important questions: First, why wasIndia trailing far behind as compared to other ship-breaking countries and failed to improve its sharein the global tonnage till middle of the eighties,and second, what helped India in achievingnumber one status as a ship-breaking country,during the current decade?

The answer to these two questions lies in thedevelopment of Alang Ship-breaking yard - anexclusive ship-breaking site which earned numberone status for India as a ship-breaking country inthe world. On behalf of the Gujarat Government,the Gujarat Maritime Board made an intensivesurvey and identified the coastline near Alang asthe most suitable site for developing ship-breakingactivity. A group of ship-breakers remained veryactive during the search process and after makinga personal visit, the group endorsed selection ofthis site for the following reasons:

l The site falls within a distinct high tidezone where the highest tide rises high upto10 to 11 meters. This is considered to bethe most favourable attribute when ship-breaking activity is undertaken throughbeaching method. In this method, the vesselbows forward during high tide and with thehelp of fully propelling power of engine thevessel is beached.

l This site in the Gulf of Khambhat and itsanchorage are the protected areas duringmonsoon and allows ship-breaking duringrainy months also.

l The coast of Alang is gently sloping andhas a long dry approach area whichfacilitates reaching upto vessel.

l The approach upto anchorage is silt-freeand anchorage is located at a short distance.

l The seabed at Alang dries up very quicklyduring the ebb period and allows easyaccessibility for all kinds of materialhandling equipments.

l The silt-free beach condition of Alang helpsships in maintaining a stable positionthroughout the process of ship-breaking.

l Further the Alang-Sosiya area is free fromany other claims for competitive uses likemerchant shipping, fishing, salt-works oraquaculture.

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This yard, established in 1983, developed slowlyin the initial period because of limited availabilityof foreign exchange for the purchase of ships forbreaking till close of 1980s. The industry made asmart progress in the current decade under moreliberalised economic policies and improvement inthe foreign exchange reserves.

1.3 ABOUT THIS STUDY

1.3.1 Background

Gujarat Maritime Board is the overall custodianfor the world's largest ship-breaking yard locatedat Alang, about 50 km south of Bhavnagar inSaurashstra, Gujarat. Stretching over 10 km of thecoastline, at present there are 183 ship-breakingberths that are leased out to private entrepreneurs.In operation since 1982, over 1,500 vessels havebeen scrapped in this yard, including warships,tankers and even oilrigs.

The ship-breaking yard has developed at Alangprimarily for reasons such as large tidal amplitude,availability of cheap labour, and a ready market.However, the nature of operation itself has its ownecological hazards. The compaction andcontamination of sediments in the littoral zone,the dispersal of pollutants in the off-shore zones,the bioaccumulation and biomagnification ofpollutants in the tissue of marine biota, thedevelopment of infrastructure, and concentrationof human population on the fragile on-shore zonesare some of them. These are serious issues and arenow viewed with concern at all levels since theseprocesses are slow but lead to irreversible damageto the ecosystems.

It is with a view to formulating an alternativedevelopment plan for the region that is ecologicallysound and to devise methods for proper regulationof activities that the Gujarat Maritime Board(GMB) approached the Gujarat EcologyCommission (GEC) to conduct a study. TheGujarat Ecological Society (GES) has actuallyconducted this study under the aegis of GEC.

1.3.2 Aims and objectives

This study seeks to analyse ship-breaking activityfrom an ecological point of view. Since most ofthe study components could not be based onrepeated samples testing over a long period of timeto determine various ecological parameters. Thestudy results, reported in subsequent chapters, maybe considered as reliably indicative and notabsolutely conclusive in final analysis. Specificrecommendations were to be made for regulatingand streamlining the activities so as to causeminimum damage to the natural environment,particularly fragile and sensitive ecotones such asthe littoral and coastal zones. The study alsoattempted an understanding of the local ecosystemdynamics necessary for evolving a practicalstrategy for the upgradation of landscape,conservation of biological diversity and bettermentof the human population that is concerned withthis industry.

1.3.3 Approach

A holistic approach was adopted replacing thetraditional sectoral approach. The entire activitywas, therefore, evaluated in the context of themacro-ecological setting taking into account thecomplex inter-relationships between different setsof natural parameters, the interactions betweenneighbouring areas and the long-termconsequences.

Since ship-breaking activity is confined to theinterface of two major ecosystems and thisnecessitates a broad understanding of both thesystems with particular reference to the dynamicsat the interface. The geological setting,geomorphological dynamics, landscapedevelopment, atmospheric features and theirrelation with the native biota, therefore, form thebasis of this study. The study, thus focuses on thethree major areas of concern, viz., the onshores,areas between the ship breaking yards and humansettlements (township), the intertidal region andthe offshore region, 5 km from the shoreline.

The study helps to identify current activities thatare causes for concern, develop options and suggestmethods for restoration and improvement. Inaddition, the study also helps in the identificationof areas for fresh intervention that will lead to

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ecologically sustainable development of the region.

1.3.4 Methodology (components andscope)

A study of this kind requires a multidisciplinaryteam of a high standard. Moreover, aknowledgeable person is required to provideguidance and leadership to this team in order toensure quality, uniformity and comparabilityamongst the sectoral studies. The views, opinionsand criticism of eminent experts are essential oncritical issues. Some of the major steps in theprocess undertaken were as follows:

1. Identification of the project leader: Aperson with long-standing experience in thefield of marine ecology and coastalenvironment was identified as the SeniorExpert and Coordinator for this study. Hisexposure at Central Marine FisheriesResearch Institute (CMFRI) and UK andadministrative experience in the Fisheriesdepartment of the Govt. of Gujarat wereperceived as major qualifications forundertaking such an assignment. He wasmainly expected to co-ordinate with variousstudy groups.

2. Constitution of the project team: Personsfrom different institutions and universitiesof the State were identified at the outset forcarrying out specific tasks. Seven majorgroups were constituted for detailed studyof the regional geology and geomorphology,vegetation, physico-chemical features of thelittoral zone, biota of the littoral zone,hydrobiological features of the offshorezone, pathogens and microbes and socio-economic features of the local humanpopulation. The team members of thesegroups belonged to Saurashtra University,Bhavnagar University, MS University ofBaroda and professional groups. Detailedwork plans were prepared by these teamsafter extensive discussions.

3. Planning workshop: A high-levelplanning workshop was organised forobtaining the benefit of knowledge andexperience of several national level experts.

In this day-long workshop, the differentwork plans were presented, discussedthreadbare by specific working groups andsuitable modifications were made (Annex1.1). The scope of work, along with thetime-frame, for each team was finalised inconsultation with the members themselves.

4. Monitoring: The progress of differentgroups was reported every fortnight. Effortswere made to facilitate field operations,obtain cooperation of different agencies andeliminate bottlenecks, if any.

Comprehensive review meetings were heldwith all the team members at periodicalintervals to obtain a first-hand feedback ofthe progress, findings and difficulties.

5. Reporting: Monthly progress reports wereobtained from each of the groups providingdetails of the field trips undertaken, analysisof samples and flow of funds. The offshoreteam provided reports after each round ofsampling, once during the post-monsoon,winter and pre-monsoon.

A mid-term report was prepared inDecember by each of the groups to presentthe first findings to the GMB. The finalreport was prepared in April, the draft ofwhich was sent out for comments.Individual discussions were held with theteam members for incorporating thesuggestions made by the reviewers.

6. Mid-course measures for strengtheningthe study: Some of the more critical aspectsof the study, such as heavy metal pollution,accumulation of oil and hydrocarbons andstructure of benthic communities werestudied separately through specialists fromJawaharlal Nehru University, MSUniversity of Baroda and CalcuttaUniversity respectively. Prof. V.Subramanian, former Dean of the Schoolof Environmental Sciences, JNU (NewDelhi) was also invited to visit the site,review the work done and propose suitablemeasures for strengthening the study.Following his advise, the heavy metalcontents were re-analysed at GSFC Science

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Centre and at JNU with the help of thesophisticated equipment.

Similarly, the socio-economic survey wasintensified to obtain a larger sample size, ahealth camp was organised for anassessment of the status of health andhygiene in the region and an indicative areadevelopment plan was prepared. Acommunication package was also preparedfor different target groups in the region. Anoverall photo-documentation was alsoattempted.

7. Development of the management plan:The entire data collected during thisexercise was presented in anotherworkshop, attended again by senior andeminent experts of the country. This datawas discussed, broad conclusions drawnand alternative management plans werederived (Annex 1.2).

8. Draft final report: The main reportconsists of two parts - Volume I presentsthe integrated analytical report of the workdone, conclusions derived and themanagement plan proposed. Volume IIprovides a set of the final reports presentedby the different teams.

1.3.5 Chapter scheme

The following chapter provides an overview of theecological features of the study area, at regionalscale, in general; and of ASSBY, in particular.Chapter 3 provides details of the ship-breakingactivity at ASSBY- its major features andprocesses involved. Once the context is established,Chapter 4 delves into the details of thegeoenvironmental features and specifically dealswith geology, geomorphology, drainage and coastaldeposits with a context to ASSBY. Following this,vegetation pattern in and around ASSBY area ispresented in chapter 5 and includes a detailed studyof the vegetation in the coastal belt with a view tounderstand the human impact. Chapter 6 providesthe ecological features of the intertidal zones - itsphysico-chemical features, and biota. Specificattempt has been made to understand the structureof microbes directly related with the oil pollution.

Chapter 7 presents the ecological features ofoffshore zone and specifically highlights thephysio-chemical characteristics of water andsediments, and biota that mainly includesphytoplanktons and benthic fauna. Chapter 8specifically investigates the status of heavy metalsin water and sediments of both intertidal andoffshore zones.. Chapter 9 provides informationon the socio-economic aspects of the localpopulation including their living and workingconditions, health and hygiene, social securityschemes etc. Finally, Chapter 10 provides amanagement plan for integrating environmentaland social concerns into the development ofASSBY. It also provides target-specificcommunication packages that may be relevant inimplementing the proposed plan.

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570 mm and average 32 rainy days a year (Choksi1989).

2.2.2 Geological setting

The Saurashtra coastal plains show a welldeveloped Cenozoic sequence comprising DeccanTrap and Laterite overlain by Tertiary andQuaternary sediments. The rocks of differentstratigraphic ages occur quite close to shoreline.Ganapathi (1981) has shown a NW-SE fault alongthe Shetrunji river and an E-W fault along theKalubhar river. These two faults are of considerablesignificance and appear to have controlled theQuaternary depositional history and geomorphiccharacteristics of the Gopnath-Bhavnagar coastalsegment. Around Gopnath the Tertiary-Quaternaryrocks show a width of about 10 km. North-eastwardof Gopnath, on crossing the Shetrunji river, thecoast shows a striking change in stratigraphy andlithology. The basaltic rocks come quite close tothe shoreline, almost 2 to 3 km only.

The Recent and Sub-Recent deposits, that includesbeach and dune sands, mudflats, alluvium and soilsshows striking differences between the northernand southern sides of the river Shetrunji. Thisreflects different processes of depositionalenvironments of the sediments on the two sides ofriver. The arenaceous sands of beach and dunesoccurring to the north of Shetrunji river are uniquein Saurashtra, and are the sole representative ofthe Holocene clastics.

2.2.3 Hydrogeology

In the study area, a variety of aquifer systems,mostly phreatic in nature, are reflected by thediversity of Tertiary and Quaternarylithostratigraphic units. The majority of aquifersare unconfined and located within the veneer ofweathered and fractured basaltic flows.

Around Gopnath, and to its west, shallow dugwellsof 17 to 20 m depths are encountered which aresituated within the Miliolite Formation whichprovides suitable aquifer conditions and henceforms a good source rock for water supply.However, the groundwater behaviour in thelimestone areas covered by the Miliolites south of

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STUDY AREA

2.1 LOCATION

The ship-breaking yard at Alang is located atapproximately 21º 24' N and 72º 12' E along theWestern side of gulf of Khambhat at a distance ofabout 50 Km from Bhavnagar, the districtheadquarters (Plate 2.1), in Talaja block. Thenearest all weather port, airport and railway stationis Bhavnagar. The area is accessible from mainlandby air, road and railways (Fig. 2.1). FromBhavnagar ASSBY can be approached through theBhavnagar-Veraval State highway no.6 via Trapajwhich is at a distance of 40 Km from Bhavnagar.An approach road of 10-12 km connects Trapajand ASSBY. An alternative route for reaching theASSBY site from the Sosiya side is almost ready.ASSBY thus, can be reached from the Alang aswell as from the Sosiya side.

2.2 REGIONAL SETUP

2.2.1 Climate

The climate of the region in general is hot andhumid except during winter between Decemberand February. The mean maximum temperatureduring summer is about 40ºC and mean minimumtemperature during winter is around 12ºC. Theregion comes under the monsoonal influenceduring June-September receiving over 100 cm ofrainfall during this period. There are largevariations in rainfall from north to south and onthe western and eastern coast of the gulf (Fig. 2.2).The Saurashtra side tends to be hotter duringsummer months and receives relatively low rainfallas compared to the Gujarat mainland. South-westerly wind blows during summer and monsoonmonths. On account of the long SaurashtraPeninsular landmass, the effectiveness

of the S-W wind is very much inhibited with thegulf. During winter the wind blows from the north.The study area, thus, experiences semi-arid to drysubhumid tropical climate with precipitation about

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Plate 2.1IRS image of the Bhavnagar-Gopnath segment, Gulf of Khambhat

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Fig 2.1 Location map of the study area.

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Fig 2.2 Rainfall in Gujarat

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Fig 2.3 Location of Gulf vis-a-vis continental shelf


Shetrunji river is prone to serious salinity hazardsdue to sea water encroachment in the freshwateraquifers.

2.2.4 Oceanographic features

The gulf of Khambhat is located in the broadestpart of the continental shelf (Fig 2.3). The gulfmarks a unique site which comes under strong tidalinfluence. Whereas the various depositionalfeatures along the different segments of the gulfcoast, as well as the offshore sand and mud depositsare typical of a tide dominated coastal waters, itsoffshore areas present a complex picture ofsediment input, transport and deposition. The gulf,along with its deposits like mud banks, shoals andunder-water ridges reveal a high tide domination,strong tidal current, low wave energy together withother variables like coastal physiography, tidalcurrents, fluvial sediment influx and riverine input.The tidal amplitude near Bhavnagar jetty is 12 mand equally high tides are known to occur in theareas around Dholera and Khambhat. Apart fromlarge changes in the water level, tides also generatevery strong currents. These tidal currents have beenresponsible for most of the depositional anderosional features in the gulf.

The gulf, by and large, forms an area of low waveenergy. Waves are generated generally by windsand the geographic location of the gulf and itsconfiguration is such that the gulf waters do notcome under the direct influence of wind generatedwaves. It is observed that the south-westerly windsgenerate relatively high amplitude waves in theopen sea (outside the gulf mouth), but they reachthe gulf coast after considerable refraction, therebylosing most of their energy.

2.2.5 Vegetation

Various authors who have described the vegetationof the area consider it as shrub savanna andscattered shrubs under Acacia-Capparis Series. Onthe coastal side the area had rich mangrove foresttill 1960s which have now degraded considerably.Most of these descriptions of vegetation are basedon the extensive surveys conducted in 1960s orearlier.

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3

ALANG SOSIYASHIPBREAKING YARD(ASSBY)

3.1 HISTORICAL PERSPECTIVE

The coast-line of peninsular Saurashtra is 900 kmlong and 22 ports out of the 42 medium and smallports of Gujarat, are located on this coast.Saurashtra has remained an outward lookingmaritime region since long and hence does notconfirm a case of peripheral region - very muchdependent on its mainland counterpart. Evenduring the colonial period, Bhavnagar (now acoastal district of Gujarat along the gulf ofKhambhat) was one of the enlightened andeconomically prosperous princely State ofKathiawar (the erstwhile name of Saurashtra).

So far as manufacturing of steel is concerned,Bhavnagar had already started re-rolling of therailway scrap, before Independence, with its firstrolling mill established in 1945. In the subsequentperiod, Bhavnagar and its neighbouring townSihor, witnessed proliferation of re-rolling mills.With the development of Shipbreaking Yard atAlang the economy of Bhavnagar received a freshimpetus. Rerolling mills of Bhavnagar and Sihorhowever were backed very much by the easy andcheaper supply of steel salvaged from the ships

broken at Alang Shipbreaking Yard.

Alang is favoured with a 10 Km dry belt endowedwith the above attributes. This has made Alangthe world's largest shipbreaking yard. The ASSBYhas reinforced growth of downstream industrieslike re-rolling, oxygen-manufacturing and LPGplants within Alang-Bhavnagar-Sihor triangle.The ASSBY may, thus, be described moremeaningfully as a "basket case" area of BhavnagarSihor sub-region. In post 1983 period and moreparticularly in post 1991 era of liberal economicpolicy, the ASSBY has elevated the economicstatus of Bhavnagar area and has become a leaderin the world of shipbreaking activity.

3.2 PRESENT STATUS

The existing site of ASSBY is comprised of 183plots of different sizes. The break-up of these plotsis given below:

Plot size Number

120 x 50 m 1080 x 45 m 2450 x 45 m 5630 x 45 m 93

Total 183

The above plots are developed along 8-10 km longcoastal strip and are provided with a service roadwhich carries heavy traffic. This road is quite busy.More than 500 service sector establishments have

Fig 3.1 Numbers and LTD of ship broken at ASSBY

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mushroomed along the service road, on the otherside of the ship-breaking plots, which cater to thedaily needs of the ASSBY people. Built-upinfrastructure of the ASSBY includes two bridgeson the service road, a bank branch, a police station,a Red-cross dispensary, a couple of public sanitaryblocks, an overhead tank for water supply and the

Table 3.1 LDT broken at ASSBY since its inception

Year No. of ships LDT Two year'sbeached (in lakhs) Moving Average

1982-83 5 0.0025 -1983-84 51 2.59 1.301984-85 42 2.28 2.441985-86 84 5.17 3.731986-87 61 3.95 4.561987-88 38 2.45 3.201988-89 48 2.54 2.501989-90 82 4.51 3.531990-91 104 5.77 5.141991-92 86 5.62 5.701992-93 137 9.43 7.531993-94 175 12.56 11.001994-95 301 21.73 17.151995-96 183 12.53 17.131996-97* 280 25.94 19.24Total 1677 112.75 -

* Projected for March 1997 Source: GMB Office, ASSBY

Table 3.2 Type of Ships broken at ASSBY during 1995

Ship Type Nos. % Share Tonnes % Share Tonnageper ship

Tankers 42 22.22 1331838 47.40 31710.4Cargo Carriers 79 41.80 721914 25.69 9138.2Bulk Carriers 11 05.82 487977 17.59 4436.5

Sub-total [1to3] 132 69.84 2541729 90.47 45285.1

Others 57 30.16 267883 09.53 4699.7

Total 189 100.00 2809612 100.00 49984.8

Source: The Gujarat Ship-breakers Association, Bhavnagar.

Analysis of data concerning economicsustainability of ship-breaking in general and ofASSBY in particular suggests the followingoutcome:l Table 3.2 shows very clearly that almost

70 percent of total vessels and 90 percentof the total LDT broken during 1995 at ASSBY

administrative blocks of Gujarat Maritime Board.The first ship was beached at Alang on February13, 1983. Thereafter, shipbreaking, at Alang hasgrown and attained a place of pride in the worldship-breaking industry. Table 3.1 and Fig. 3.1 givesan account of the growth of shipbreaking at Alangsince its inception.

were of three major types, viz., Tankers, CargoCarriers and Bulk Carriers. Average life of ship isconsidered between 20-25 years and ships havingmore than 25 years of age are considered notseaworthy and constitute supply for breaking.Table 3.3 gives an account of ships of more than

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25 years of age, considering them as available inthe global market for breaking. In GRT termsapproximately 32 million tonnes and in LDT terms(considering 1/3 of GRT as LDT), 11 milliontonnes supply may be taken as available forbreaking. Tankers, Bulk Carriers, and CargoCarriers contribute 92 percent share in the totalsupply. Currently, India's share in the total LDTbroken is approximately 33 percent. Granting the

Table 3.3 Global availability of ships and tonnage for breaking by ship type

Ship Type No. of Ships having mor GRT Percentage inthan 25 years of Age Total GRT

Tankers 1840 5775530 18.0Cargo Carriers 587 7811765 24.3Bulk Carriers 7523 15955919 49.7

Sub-Total 9950 29543214 92.0

Others 4373 2571288 8.0

Total 14323 32114502 100.0

Source: Lloyds Register Statistics (1995)

Table 3.4 Costing (based on thumb-rules) per LDT at ASSBY

SN Items Rs. (per LDT)

1. Purchase of ship [ @ $165 LDT, conversion @ Rs. 37.50] 6154

2. Duty [Custom & Excise ] 738

3. Cutting Cost[i] LPG O2 500[ii] Wages 300[iii] Interest 200[iv] Delivery & Beaching 150[v] Overhead 50

Sub-total 1200

4. Total [1-3] 8092

5. Average Selling Price 8200

6. Average App. Profit 100

LDT. The industry has a history of buyingships even at a rate of $220 per LDT. Theship prices are determined by global marketposition of ships offered for demolition.Granting the fact that India has emergedas a dominant shipbreaking country, andthat there are no supply side constraints,India may continue enjoying the currentpurchase price of ships [$ 165 per LDT]

which stands quite competitive.l The second item in the cost structure is the

cost of cutting. In this regard, wagesconstitute 25 percent share (Table 3.4).More than double of the amount of entirewage bill is remitted by ship-breakingindustry to the Government treasury in theform of custom and excise duty. The nodalagency [GMB] earns half of the amount ofthe total wage bill paid to more than 30,000workers.

possibility that the present structure of competitionin the market remains the same and India is in aposition to claim its share, the country may verywell go upto breaking 4 million LDT per year. Itis evident that both in terms of number andtonnage, there are no supply side constraints innear future.

l The largest cost component in ship-breaking is the ship itself. The currentbuying price of ship is around $ 165 per

16


3.3 MODUS OPERANDI

The total ship-breaking activities encompassoffshore, littoral, and on-shore zones.

The offshore processing starts with the arrival ofa ship at Alang anchorage, when personnel fromcustoms department, agents, marine surveyors andthe buyer inspect the vessel, and final purchasingprocess is completed if the ship conforms with thepurchase deal. Simultaneously, relevant permissionis sought from GMB and excise and customsdepartment for beaching of the vessel. This isaccomplished, at appropriate plots in the intertidalzone, with the help of professional crew. Eitherthe ships' engines are used or else a tug is employedto move the vessels to their final resting positions.The undersurface of the hull of these ships aredragged over the rocky substrate upto its finalresting position through a process known as"forced beaching".

The major ship-breaking processes areaccomplished at the littoral zone. These mainlyinclude the removal of super-structures and cuttingof the ship's hull, engine and the propeller.Material removed from the ship consists of avariety of items usually expected in a ship. Theseoperations include:

l Pumping out of ballast water, fuel oil andlubricants. Bunker oil from the enginebottom is removed after dismantling theengine.

l Dismantling and removing of furniture,lifeboat, loose cables, fire-fightingequipments, ladders, window anddoorframes etc.

l Removing of electrical and navigationalequipments, nylon and steel ropes, shackles,machinery spares etc.

l Removing of some of the winches, mastsand derricks.

l Dismantling and removing dieselgenerators, boilers, air compressor, pumpsetc.

After the removal of electrical and othermiscellaneous items, the vessel is cut vertically byoxygen-LPG torches into big blocks. These blocksare of the sizes/weight of about 10 tonnes whichdrop onto the beach on either side of the vessel.These dismantled pieces are pulled on to the shorewith the help of winches during the low tide. Asthe size and weight of the vessel is reduced, it ishauled closer to the shoreline by winches duringthe high tide. Finally, the hull bottom is cut andpulled to the shore. Normally the process ofbreaking a ship of 4000-8000 LDT takes 3-5months.

The major equipments used in beaching of a shipand pulling the large blocks of steel are:

l 10-15 tonnes' capacity winches generallywith 100 HP automotive diesel engine(Plate 3.1).

l 10-20 tonnes' capacity mobile crawler crane

l 20 tonnes' derricks generally reclaimedfrom vessels.

Activities in the on-shore zone mainly compriseof cutting the big blocks into smaller transportablepieces, and transferring these smaller blocks to thedesired destination.

The essentials for de-welding the ships are LPGand oxygen gas, LDO and lubricants, withassociated machineries, and equipments forpersonal protection. Big blocks are cut into platesweighing 2-5 tonne in the plots (Plate 3.2) and aretransported out. Small pieces of rusted, broken,deformed steel are sold as scrap. The generalappearance of a yard is that of a junkyard withmetal pieces and, oxygen and LPG cylindersscattered all over (Plate 3.3). The big pieces aregenerally near the tidal area and smaller ones areon-shore.

3.3.1 Products of ship breaking

Ships procured for demolition usually carrydifferent types of organic and inorganic materialssome of which pollute the marine environment ifnot controlled during dismantling. The material

17


that is released during ship-breaking include:

l Oil Fuel and lubricants

l Oil sludge in oil tankers and oil/bulk/orecarriers

l Solid wastes such as glass wool,thermocole, plywood, timber

l Heavy metals and other chemicalconstituents of paints and coatings

l Remnants of toxic chemicals in the cargocompartments.

The oil bunker/tank of the ship is located eitherunder the engine room or in bottom hold of theship. As the marine bunker oil and the diesel oilhave a high market value, bulk of these oils arepumped out from the tanks and the residual oil inthe bottom layers are removed by manual scrapingand are transported to the shore for sale. It is alsonecessary to remove this oil from the tanks beforethey are cut into smaller blocks. Crude oil tanksof oil tankers and oil/bulk/ore carriers containconsiderable amount of oil sludge.

18


Plate 3.2 Large Blocks being cut into small blocks

19


20

Plate 3.3 A view of Alang-Sosiya ship-breaking yard


4

GEOENVIRONMENTALFEATURES

Geo-environment of any area decides the longevityof mega-developmental projects. This holds trueeven more in the coastal regions, which are underthe continuous influence of ocean dynamics.Geological formations under coastal erosion formprovenance for sediments of littoral and offshoreregion and determine the composition of thesesediments. Special physical features, namely,movement of water across the gulf, high tidalamplitude, strong energy condition, large quantityof suspended sediments and littoral zone withrocky as well as soft substratum create an array ofarea specific yet unique coastal conditions. Anunderstanding of various parameters of geo-environment is, therefore, a pre-requisite for sounddevelopmental planning, especially in the coastalareas. Keeping this in view, while studying theoverall influence of ship-breaking activities atAlang, on local as well as regional environment,a special attempt has been made to study the geo-environmental conditions of the area in depth.

4.1 GEOLOGY

4.1.1 Structural setup

The tectonics of the Saurashtra coast (Gopnath-Bhavnagar segment) have strongly influenced thecoastal geomorphic evolution, as the configurationand evolution of the gulf of Khambhat is areflection of the various major and minor faults ofthe Cambay basin.

Structural framework of the coastal segmentprovides a combination of numerous regional faultsrelated to the Cambay Basin. The N-S Saurashtracoast marks the site of major lineament (WesternCambay Basin Boundary Fault), which Ganapathi(1981) has referred to as Ghogha-Sanand Fault.Ganapathi has also shown a NW-SE dislocationalong Shetrunji river (Shetrunji Fault); and E-WKalubhar Fault, following broadly the course ofthe Kalubhar river. While examining the faultrunning east of Piram Island, he has invoked asmaller N-S fault in between Ghogha and Piram(Fig. 4.1). The Figure also shows the structuralframework of the area based on the works ofONGC, Ganapathi (1981), Islam (1986) andSridhar (1995).

4.1.2 Stratigraphy

The Gulf of Khambhat and its environs comprisemostly of Cenozoic (younger than 65 million years)depositional sequences, and are dominantlymarine. The Tertiary rocks (marine sedimentatires)rest unconformably over the Deccan Trap volcanicrocks and constitute the Cambay Basin. A largepart of the gulf coast does not show any significantoutcrops of the Tertiary rocks but their subsurfacepresence, stratigraphy and lithology have beenreported by the ONGC (Chandra and Chowdhary,1969) (Fig. 4.2). However, a few exposed Tertiariesoccur on the Saurashtra side of the gulf. Ganapathi(1981) has given details of the stratigraphy of theSaurashtra Coastal Block. Table 4.1 shows thestratigraphy of the Bhavnagar-Ghogha coastalsegment.

The Saurashtra coastal plains show a welldeveloped sequence comprising Tertiary andQuaternary sediments overlying older Deccan Trap

Table 4.2Tertiary-Quaternary stratigraphic sequence around Gopnath-Methla area

Alluvium and Mudflats Holocene

Miliolite Formation Pleistocene

Gaj Formation Lower Miocene

Laterites Palaeocene

Deccan Traps Cretaceous-Eocene

21


Fig 4.1 Structural setup of Gulf of Khambhat

22


Fig 4.2 Geology around Alang

23


and Laterite. The Cenozoic rocks of differentstratigraphic ages occur quite close to shoreline.Ganapathi (1981) has shown a NW-SE fault alongthe Shetrunji river and an E-W fault along theKalubhar river. These two faults are of considerablesignificance and appear to have controlled the

Quaternary depositional history and geomorphiccharacteristics of the Gopnath-Bhavnagar coastalsegment. Around Gopnath the Tertiary-Quaternaryrocks show a width of about 10 km. The following(Table 4.2) Tertiary-Quaternary stratigraphicsequence is encountered around Gopnath-Methla.

Table 4.1Stratigraphy of the Bhavnagar-Ghogha coastal segment

ERA PERIOD AGE FORMATION LITHOLOGY

Holocene Recent deposits Alluvium, Beach and Dune___________ _________________ ______________________Pleistocene to Lakhanka Formation Soft friable ferruginousEarly Holocene sandstones and sands with layers

rich in agate pebbles andintercalations of grey colouredclays

___________Mio- Pliocene

Unconformity ______________________

Piram Beds Hard and well cementedfossiliferous conglomerates withalternation of sandstones andclaystones______________________

___________Disconformity

Fossiliferous conglomerates, Bhumbli grits and argillaceous sandstones Conglo- with intercalations of claysmerateMember

___Unconformity_____LowerMiocene

Grey and yellow coloured claysRatanpur and marls with gypsum layers.Clay At the base, basal conglomeratesMember and argillaceous sandstones with

cross lamination______________________

Unconformity___________Palaeocene Unstratified red, brown, and

Lateritic yellowish brown hard lateritesrocks with clay pockets

___________Cretaceous __Deccan Trap__ Variety of basaltic lava, felsite

and rhyolite with dolerite dykes

(Source: Merh 1997)

C

E

N

O

Z

O

I

C

____

ME

SOZOIC

Q

U

A

T

E

R

N

A

R

Y

T

E

R

T

I

A

R

Y

_____

24


Northeastward of Gopnath, on crossing theShetrunji river, the Ghogha-Bhavnagar coastshows a striking change in stratigraphy andlithology (Table 4.3). The basaltic rocks comealmost 2 to 3 km close to the shoreline. Lateritesand Gaj rocks are exposed along the coastline itself.Calcareous facies (Miliolites) changes over to anon-carbonate facies (Lakhanka Formation).

The Recent and Sub-Recent deposits, that includesbeach and dune sands, mudflats and alluvium soilsshow striking differences between the northern andsouthern sides of the river Shetrunji. This reflectsdifferent processes of depositional environmentsof the sediments on the two sides of river. Alangis situated on the northern side of the riverShetrunji, where the beach and dune materials areessentially arenaceous and consist of fine tomedium grained sands. Near the upper tidal limit,the beach material becomes of shingle size and ismade up of rounded to sub-rounded fragments ofquartz, chalcedony, agate and basalt and Gaj rocks.A broad and continuous well developed beach isseen in this part. Dune ridges are ratherdiscontinuous, though a good development of dunecomplex is seen from north of Hathab Bungalowto Kuda village and also near the village Alang.The arenaceous sands of beach and dunesoccurring to the north of Shetrunji river are uniquein Saurashtra, and are the sole representative ofthe Holocene clastics.

4.1.3 Hydrogeology

Groundwater in coastal area is mostly saline, andavailability of sweet water is very restricted. Avariety of aquifer systems, mostly phreatic innature, are reflected by the diversity of Tertiary

and Quaternary lithostratigraphic units in the studyarea.

South of Shetrunji the TDS content is low, and toits west, shallow dugwells of 17 to 20 m depth areencountered which are situated within the MilioliteFormation. Generally, Miliolite provides suitableaquifer conditions and hence forms a good source

rock for water supply. However, the groundwaterbehaviour in the miliolites limestone in coastalareas is prone to serious salinity hazards due toseawater ingress in the freshwater aquifers.

The water tables in aquifers from Shetrunji rivernorthwards to Ghogha show a marked differencein their nature between that of the coastline and ofthe backshore areas. The former consists ofaccumulated sweet water in the coastal sands andin the underlying Gaj Beds, but this gets saline inthe premonsoon months. Such type of wells areobserved in the villages Kuda, Ratanpur and Alangwhere the average depth of sweet water phreaticaquifer is from 7 to 10 m. On the other hand, inlandcoastal areas the wells are free from influence ofsea water ingress, and hence hold sweet water,which is used even in small scale irrigation. In theDeccan Trap country the majority of aquifers areof unconfined nature and located within the veneerof weathered and fractured basaltic flows. Theaverage depth of dugwells is of the order of 12-15m.

The coastal area of Ghogha and Bhavnagar hasgot its own distinct hydrological conditions. Herethe demand of sweet water is being met throughsurface ponds and shallow dugwells, and theaverage depth of sweet water availability is only 5m. The water at greater depth is saline as is seen

Table 4.3 Stratigraphic sequences N-E of Gopnath coastal segment

Mudflats, Beaches & Dunes Holocene

Lakhanka Formation Pleistocene to Holocene

Piram Beds Mid-Pliocene

Gaj Formation Lower Miocene

Laterites Palaeocene

Deccan Traps Cretaceous-Eocene

(Source: Merh 1997)

25


from a well at village Akhvada where brackishwater is encountered at 7 m depth (Table 4.4).

Table 4.4Hydrogeological Conditions in the coastal segments

Well Aquifer Village Name Total Water Level [m]No. Formation Depth [m] Pre Post

1 Methla 07.00 06.50 04.802 Miliolite Jhanjmer 19.50 18.50 10.603 Pithalpur 20.00 16.00 09.204 Gopnath 17.00 12.00 07.50

56 Fluvio-marine Saltanpur 09.00 07.20 04.607 sediments Dakana 04.50 04.00 01.50

Lilivav 17.00 13.50 08.70

8 Deccan Trap Kathva 18.00 16.00 12.809 Alang 17.00 15.00 09.60

10 Sandstone Mithivirdi 20.00 19.00 15.40

11 Dunal Sand Hathab 09.50 08.00 04.50

12 Deccan Trap Badi 15.00 10.00 06.45

13 Dunal Sands Kuda 05.00 03.00 02.00

14 Kuda 09.50 09.00 02.60

15 Sandstone Nava Ratanpur 05.00 04.00 02.20

16 Ghogha 11.00 05.00 01.80

17 Deccan Trap Thoradi 12.00 09.00 03.70

18 Budhel 11.50 07.00 03.40

19 Trap covered by Akvada 07.00 04.00 02.90fluvio-marinesediments

20 Deccan Trap Karnej 35.00 29.70 20.40

(Source: Merh 1997)

26


There are no significant data available on thechemistry of the groundwater. The chemicalquality of ground water is dominantly influencedby seawater ingression and inherent salinity ofmarine formations, and percentile variation ofvarious dissolved constituents provides a goodindication of the overall quality of the groundwater(Table 4.5; Islam 1986). In the area betweenShetrunji and Kalubhar rivers, the groundwater issaline and the TDS ranges between 474 and 3374ppm. Sodium dominates over all other cations.Bicarbonate and chloride dominate over all otheranions.

Table 4.5Chemical quality of Ground water

Sam. Depth TDS Cations [ppm] Anions [ppm]

No. [m] [ppm] Na K Ca Mg CO3

HCO3 Cl SO4

pH

1 06.50 2669 1100 42 73 91 30 488 540 238 7.52 18.50 474 160 3 1 11 7 442 670 85 7.73 16.00 645 180 1 6 2 30 442 465 68 7.64 12.00 1225 130 2 109 48 - 153 603 56 6.95 07.20 1905 270 39 120 79 - 198 735 346 7.16 04.00 2541 560 35 67 64 60 885 845 620 7.77 13.50 943 125 1 95 106 - 290 358 256 7.28 16.00 657 50 2 14 62 - 259 248 44 7.39 15.00 645 90 3 31 51 15 229 355 262 7.410 19.00 478 65 5 27 21 - 198 952 96 7.311 08.00 2990 500 3 69 35 120 610 1100 242 7.112 10.00 790 80 2 2 31 - 381 465 43 7.813 03.00 1110 220 42 23 53 - 503 867 398 7.614 09.00 1153 315 1 11 52 - 702 1166 567 7.715 04.00 1003 235 2 9 38 45 290 1228 64 7.716 05.00 3118 535 4 70 108 30 275 1242 620 7.417 09.00 854 95 1 7 35 - 244 177 76 7.518 07.00 1238 270 9 8 34 - 473 355 148 7.719 04.00 3374 560 8 93 201 - 580 348 284 7.3

(Source: Merh 1997)

are small, shallow and never exceed more than 50km in length. Though most of the streams andrivers of the study area are ephemeral, theirdrainage patterns show considerable diversity (Fig.4.3). The breaks in the lower reaches of the riverprofiles, linear extension of the high orderchannels, and the emergence of new smallindependent streams all along the coast, and thedeflection of the river courses also suggest changein sea level. Most of the streams follow

straight courses, some have deflections at variousangles either due to joint intersection or due to

4.2 GEOMORPHOLOGY

4.2.1 Drainage

The coastline between Bhavnagar and Gopnath(Shetrunji River) forms a narrow NNE-SSWtrending coastal plain backed by low hill ridges.Several small rivers and seasonal streams, cutacross the plains and meet the gulf barring theriver Shetrunji. These streams and rivers, however,

strandline change which reveals structural controlon the stream course.

The lowermost reaches of the stream courses arerather wide and curved though not meandering.The beds are full of sediments of different sizes.Deposition being dominant, the beds do not showany worthwhile erosional feature. The ratio ofwidth to depth is quite high in comparison to theupper and the middle segments of the streams.

27


Fig 4.3 Drainage Pattern around Alang

28


The only perennial stream in the study area is theriver Shetrunji which originates from the Girrange, about 150 km away, and enters the coastalplains with final stage of growth, draining basalticrocks throughout its course. Near its mouth it formsan estuarine delta. The characteristics of otherstreams are given in Table 4.6.

4.2.2Landform

The geomorphic attributes of the study area,especially the landforms and the drainage patterns,reveal interesting combinations of erosional anddepositional processes that operated during theCenozoic Era over a coastal terrain that wassubjected to frequent sea level changes. Thestructural features of the trappean rocks - faultingand jointing, contributed a major share in evolvingthe landforms and drainage. The shapes,configuration and slopes of the erosional landformsare all dependent on the factors enumerated above.The various river courses and their tributaries tooshow close relationship with the faulting andjointing of the trap rocks.

4.2.2.1 Saurashtra coastal plains

The landscape of the coastal plains of southeasternSaurashtra peninsula of which the study area formsan important segment, has preserved within it,imprints of the various weathering anddenudational agencies of more than one generation(Fig 4.4). The coast typically marks area of upliftduring the Quaternary period and the landscapeis youthful. The various sub-aerial processesinclude

weathering, mass wasting, fluvial erosion andsediment transport and formation of flood plainsand terraces. The hinterland landforms, i.e., therocky fringe and the coastal plains that lie behindthe shoreline, are both erosional and depositional.

29


Fig 4.4 Coastal landforms around Alang

30


Table 4.6Characteristics of the stream longitudinal Profiles

All along the coastline between Bhavnagar andGopnath the interior flank is made up of trappeanhilly terrain comprising conical and flat-toppedhills and ridges, dissected by small streams. Aerosion product of a jointed basalt flow countrydotted with dykes, the area is characterised byundulating rolling topography. South of Shetrunjiriver these hills and ridges form the eastwardextension of the Gir Range, and merges with thecoastal plain at southeast. On the north of river

Shetrunji the Khokhra range trends N-S with steepeastern slope, abutting rather abruptly against thecoastal plain, and the foothill slopes show apronounced accumulation of products of masswasting.

The coastal plains nearer the shoreline provide agood example of assorted depositional landformsof Tertiary and Quaternary periods, dominantlyproducts of fluvial processes. Evidences of

Name of Stream, Altitude,m Nature of Gradient Remarks the stream length Km Max Min the profile

Adhewada-Malesari Nadi

21.500 140 18 Concave 0.0057 High Concavity near source might be due to steep slope

Bhumbhli-Malesari Nadi

12.500 85 12 Gentle Slope

0.0058

Koliyak-Malesari Nadi

24.500 240 12 Concave with three breaks

0.0093 There are three breaks, 1st break at 2.5 km from source is due to

Ramadasi Nadi

12.500 80 10 Concave with one break

0.0056 Tansa fault, IInd and IIIrd breaks at 17.4 and 19 km from source

Mithivirdi Nadi

14.200 80 8 Gentle slope

0.0051 area are due to rejuvenation. One break at 8.8 km from source due to rejuvenation/sea regression

Manari Nadi 20.700 140 8 Concave 0.0063 Bagad Nadi 38.600 280 7 Concave

with one break

0.0077 One break at 5km from source is due to local fault

Bhadrod Nadi

26.200 160 7 Concave 0.00582

Longdi Nadi 14.100 60 7 Very Gentle slope

0.0037

Roshia Nadi 13.600 60 7 Very Gentle slope

0.0039

31


prolonged history of deposition followed by someerosion are distinctly recorded in the area justbehind the actual shoreline and the variouslandforms recognised are (a) terraces and floodplains, (b) point bars and bar islands, and (c)abandoned channels.

The river Shetrunji and Malesari group of streamshave cut their own flood plains and their channelsare flanked on both sides by hanging terraces, oneabove the other; most of the terraces are paired.The upper terrace level has been recorded at theheights ranging from 8 to 10 m; the lower onesoccur at 2 to 4 m above the riverbed. The variousterraces represent successive flood plains of thepast and reveal a sequence of depositional anderosional events of the Quaternary times.The area also shows good examples of valley filldeposition caused by the impounding of the riverwater due to transgression of sea; the regressionthat followed resulted into vertical downcuttingand carving of cliffy terraces. Point bars and islandsin the riverbeds are the other interestingdepositional features. These are the products ofdeposition due to velocity variation of the streamflow.

The rivers like Shetrunji, Vatrej-Malesari Nadi,Bhadrod Nadi and Talgharda Nadi showabandoned channels in their lower courses, whichcould be related with sea-level changes.

4.2.3 Coastal deposits

4.2.3.1 Tidal flat deposits

Tidal mudflats which constitute, by far the mostextensive deposits appear to be the product ofstrong tidal currents operating within the gulf.Islam (1986) endeavoured to provide a bird's-eye-view of the nature of sediment load deposited by

the tidal waters of the gulf. In this report samplesfrom 19 locations have been included.

It has been observed that the major bulk of tidalmud in all parts of the gulf coast is made up of siltsize particles, their proportion varying from 60 to75%. The sand fractions are always less than 6%,while clay fraction varies from 15% to 30%. Thetidal muds thus fall within the `clayey silt' to `silt'category. It has also been observed that the largerparticles (sand + silt) are dropped at the high waterline during flood tide and the finer sediments arecarried back during ebb tide.

4.2.3.2 Beach deposits

Compared to the extensive development of tidalmud deposits, that of sandy beaches is rathersubordinate and restricted. Beaches first appearnear Ghogha and extend southward upto Shetrunjiriver mouth, forming a narrow more or lesscontinuous stretch. Beyond this river, the beachsands increase in bulk, dimension and lithologicalcharacteristics.

South of Shetrunji river, the beach has developed,and sand accumulations occur almost continuouslyfrom Gopnath to Methla and beyond. The particlesize is dominated by coarse to fine sand (Table4.7), and are rich in carbonate content because of

their richness in bioclastic grains, mainlyforaminiferal tests and molluscan shell fragments.The carbonate content is 30 to 37% at Ghogha,and almost 60% at Methla. Quartz is the dominantnoncarbonate constituent.

Table 4.7Statistical parameters of beach sands

Sample Location Mean in phi scale Standard deviation SkewnessMethla 2.84 0.58 -0.81Gopnath 2.96 0.42 0.41Alang 2.59 0.85 -0.01Kuda 2.73 0.44 -0.07Hathab 2.34 0.62 0.009Piram 2.63 0.35 -0.77

(Source: Merh 1997)

32


4.2.3.3 Shoreline morphology

The shoreline of the coast between Bhavnagar andGopnath provides an interesting assemblage oferosional and depositional features, related totectonic and eustatic factors. On the whole, thecoastline between Bhavnagar and Mahuva hasbeen gaining land; overall effect is that of aprogressive regression with resulting emergenceof new land. On the basis of differentmorphological features, the nature of sedimentsand their transport and sedimentary history, theshoreline can be subdivided into following discretesedimentation zones:

a) Bhavnagar-Ghogha (Estuarine)

b) Ghogha-Mathawada (Beach)

c) Shetrunji Delta (Estuarine)

d) Gopnath-Mahuva (Dune and Cliff)

Each segment of the shoreline exhibits botherosional and depositional features, but theirrelative proportions vary from segment to segmentdepending on the nature and intensity of the twoprocesses. Bhavnagar-Ghogha section, whichforms the northern extremity of the area showsgeomorphic features related to various depositionalprocesses operating at the present time. But thereare certain landforms like ancient marine terracesalso, related to an earlier period when erosionalprocesses were effective along this part of theshoreline. The beach along the Ghogha-Mathawada consists mostly of depositionallandform mainly beach and dune ridge complex.The erosional features are restricted to the lowerpart of the foreshore and are marked by wave-cutplatforms. The well-developed beach and duneridge complex evidently point to the dominanceof depositional processes. Shetrunji delta is madeup of a number of depositional landforms formeddue to the interaction of fluvial and marineprocesses under conditions of fluctuating sea leveland perhaps tectonism.

Across the Shetrunji river towards Gopnath andfurther west, the shoreline dominates in erosionallandforms, and on account of the irregularity inthe shoreline configuration, processes of marineerosion predominate. The indented shoreline from

Ghogha towards Mahuva is marked by submergedand dissected aeolianites (Miliolite). Here wedescribe in brief the characteristics of the Ghogha-Mathawada section to which our study areabelongs.

4.2.3.4 Shoreline between Ghogha andMathawada

From Ghogha to Kuda, the coast extends almostsouth-east, and then takes a turn to south-west,and runs straight upto Mathawada. This part showsseveral interesting foreshore and backshorefeatures, though the berm line dividing the two isnot well defined.

The foreshore features mainly comprise of wave-cut platform, beach and mudflat. The intertidalplatform which makes an erosional feature of waveaction is seen as a very seaward sloping rockyplane. From Ghogha upto one km south of HathabBungalow the platform is of Gaj rocks, and furthersouthwards it is made up of laterite and Lakhankarocks. Width of this zone varies from 500 to 1,500metre. Good example of this wave-cut platform isseen near Ghogha village. The platform is coveredby a thin veneer of tidal mud all along its lengthwhich gets washed out during monsoon. While theplatform is mostly devoid of any vegetation, theGaj rocks support some shrub growth.

A beach extends all along the coast from Kuda toMathawada. Its width varies from 25 to 200 m,narrow at the south and broad at the north. Betweenthe Kuda guesthouse and Ghogha, the beach isdissected by the Ratanpur Creek. The beach slopesvery gently southwards. Landward the beach, isflanked by backshore dunes. The berm line is notat-all well defined and the beach abruptly abutsagainst the coastal dune ridge. The beach materialvaries in size from very fine sand to very coarsepebbly gravels and is made up of quartz, agate,chalcedony, with small proportions of shellmaterial and rock fragments etc. The beachmaterial is derived from the intertidal rockyplatform, material brought by the rivers frominland areas and sediments brought to the gulfwaters by the Mainland Gujarat rivers andtransported by longshore drift.

Towards Ghogha, the beach almost tapers out

33


because of a marked change in the shorelineconfiguration and sand accumulation. The beachat Ghogha is made up of shingles only. Evidentlythe imbalance caused by the interference betweenwave action and longshore currents, appears animportant factor responsible for the exclusiveaccumulation of shingles, the sand particles beingcarried further N-N-W.

The backshore features comprise only coastalaccumulations, and studies have shown that thesecoastal dune ridges belong to two generations.They are:

l A dune ridge complex immediately behindthe beach, and evidently related to the present dayshoreline.

l An ancient beach and dune topography justat the back of the present day dunes which indicatesa post higher strandline.

The present day coastal dune ridge complex isobserved right from the Kuda guesthouse to as farsouth as Mathawada. The width of the ridge variesfrom 10 to 50 m. Its height varies from 3 to 20 m,and is marked by a typical dunal topography. Aboutone km south of Kuda, a maximum height of 27m is recorded. The dune-ridge complex extendsfor about 30 km parallel to the shoreline, withfrequent breaks on account of dissections bynumerous inflowing streams. The dunes are allunconsolidated, though in recent yearsconsiderable plantations have been made by theForest department to check the inward migrationof the sands.

Behind these coastal dunes, there occurs an olderdune-beach complex south of Hathab Bungalowupto Mathawada. They rest over the LakhankaFormation, and are considerably dissected anderoded, and provide a rolling topography. Thisgeomorphic feature provides an excellent evidenceof a past higher strandline, 6 to 8 m above thepresent sea level.

4.3 OFF-SHORE: THE GULF OFKHAMBHAT

4.3.1 Bathymetry

The bathymetry of the gulf is very unique. Thetectonic and sedimentation factors have played adominant role in imparting diversity of the gulfbathymetry. The features of the gulf bottom areessentially products of graben faulting related tothe tectonics of the Cambay basin, and selectivedeposition of sediment load by tidal currents.

The gulf can be divided into three parts from thebathymetric point of view, e.g., Inner gulf (northof Ghogha Dahej E-W line), Outer gulf (betweenGhogha Dahaj and Gopnath-Surat E-W line) andopen shelf outside the gulf (south of the Gopnath-Surat E-W line upto Daman).

The inner gulf is very shallow, never exceeding indepth beyond 27 m (Fig. 4.5), and is replete withmudbanks and shoals. The bottom topography herecomprises N-S extending banks and underwatershoals with intervening shallow channels whichare only 10 to 12 m deep.

The outer gulf is deeper, broader and has variedfloor topography. It is made up of underwaterchannels and ridges which tend to diverge andopen up southward, and some of the ridges riseabove the low water line. The channels form thedeeper seas in between the various parallelunderwater ridges. The deepest portion of the gulfcomprises of median channels as deep as 45 to 49m, located east of the Piram island, and

three diverging channels in the southern portionjust outside the mouth of the gulf.

The open shelf located outside the gulf forms apart of the continental shelf. It overlooks the gulfmouth and forms an open flat shelf area averagingfrom 30 to 35 m deep dissected by a number ofchannels with intervening sandy ridges which tendto converge towards the gulf mouth. Thedevelopment of these underwater sandy ridges ofthe order of 30 to 80 km long outside the mouth ofthe gulf is illustrative of the phenomenon oftransport and deposition by tidal currents whichare presently performing an equally important roleof controlling the tidal current directions and thepattern of sediment transport and deposition.4.3.2 Tides and tidal currents

The gulf forms an area of highest tides along thewest coast. Fig. 4.6 illustrate the tidal range in the

34


Fig. 4.5 Bathymetry of Gulf of Khambhat

35


different parts of the gulf, observed by Islam(1986). The computed time differences for the peaktides at various locations with reference to hightide at Bhavnagar Jetty are presented in Table 4.8.

Table 4.8

Time differences for peak tides withreference to high tide at BhavnagarJetty

Location Time differences

Methla -80 minGopnath -70 minPiram -15 minGhogha -10 minKhambhat +60 minDahej -70 minHazira -70 min

(Source: Merh 1997)

Apart from the phenomenon of the rise and fall ofwater level, the tide generates very strong tidalcurrents. These currents during the flood and ebbtides have been responsible for most of thedepositional and erosional features in the gulf. Vastcoastal mud deposits, mudbanks,

shoals and underwater linear ridges showresemblance to the type diagram for macrotidalcoast (Hayes 1979), a shallow water zonedominated by high tide. The geographic locationand configuration of the gulf with respect to theSaurashtra coast and the south Gujarat mainlandcoast, the broad extensive shelf zone within whichthe gulf is located and the dominant direction ofthe monsoonal winds, in combination with theirregular floor of the gulf bottom have beenresponsible for the pattern and behaviour of tidesand tidal currents.

The tidal current directions as observed on satelliteimagery establish following facts (Islam 1986):l the current directions during flood and ebb

tides have almost identical paths,l the tidal currents bothways follow the

bathymetric feature of the gulf,l the fanning pattern outside the mouth of

the gulf is closely related to the presence ofnumerous underwater rhythmic linear

ridges which regulates the entry and exitof the tidal water; and,

l the unevenness of the inner gulf bottomcharacterised by numerous mudbanks andshoals, and the obstruction caused by thePiram island are also the factors thatgoverned the movement of tidal waters.

A fact worth noting is that the various rivermouths, especially of Sabarmati, Mahi andNarmada, react differently to the rising andreceding tides. During the flood tide, the inflow ofriver waters would experience a resistance, therebyslowing down or even reversing their flowdirection. However, during the ebb tide the riverwater would join the seawater in its outwardjourney. From these observations, it stands out thatthe tidal current are rather week at the river mouthduring flood tide, whereas they are quite strongduring the ebb tide.

The proportion of suspended load is directly relatedto the shallowness of the gulf inlet, mudflats,mudbanks, shoals and other offshore features. Thepattern of concentration is also indicative of thetrends of total currents and bathymetry. Theproportion of sediment load near or outside thegulf mouth is much less. This points to a vital factthat incoming tidal waters are less loaded withsuspended sediments. The sediments are carriedby tidal currents, such that the influx is both fromthe south Saurashtra coast as well as from the southMainland coast. During receding tide there is anoverall decrease in the sediment content. At thepeak high tide the stagnation of water would causesettling of the suspended sediments especially thesand and the silt size fraction. Heavy concentrationduring ebb tide is restricted to the inner tidal muddyareas only. The median portion of the gulf showsonly moderate to slight concentrations exceptwhere the tidal water flow over the submergedridges. The distribution patterns of sediment loadduring different seasons are observed to be quitevariable.

Along open coast, the normal difference betweenhigh and low tide is only a metre or so, but withinrestricted areas like a gulf the tidal range alwaysincreases. In the gulf of Khambhat, the pattern ofvariation in the height range of high and low tidesis strikingly different between the mouth and theinterior part. The height of the tide at Bhavnagar

36


Plate 3.3 A view of Alang-Sosiya ship-breaking yard

37


jetty is +12 m and equally high tides are indicatedin the areas around Dholera and Khambhat.Main causes of very high tides could be listed asthe convergence of shorelines, river water input,and shallowness of the gulf. Strong southwesterlymonsoonal winds also augment the height of thetides under stormy conditions, thereby causingextensive flooding of the low lying coastal areasof Saurashtra and Bhal.

4.3.3 Waves

The gulf, by and large forms an area of low waveenergy. Waves are generated generally by windsand the geographic location of the gulf and itsconfiguration is such that the gulf waters do notcome under the direct influence of wind generatedwaves. Unlike the other coastal areas of Saurashtraand of South Gujarat which experience northwesterly winds, the gulf is protected by theSaurashtra landmass. A perusal of the climatic datareveals that for most part of the summer andmonsoon months, strong winds blow from W andSW, whereas during winter months landwardbreeze blow from N or NNE. It is observed thatthe southwesterly winds generate relatively highamplitude waves in the open sea (outside the gulfmouth), but they reach the gulf coast afterconsiderable refraction, thereby losing most of theirenergy. Wave height observed during differentseasons are presented in Table 4.9

Table 4.9 Seasonal Wave height atdifferent location along the coast

Locations Winter M onsoon Summer

Methla 2-3 m 4-5 m 2.5-3.5 mGopnath 1.5-2.5 m 3-4 m 2-2.5 mGhogha 1-2 m 2-3.5 m 1.5-2 mKhambhat 0.5-1 m 1.5-2 m 1-1.5 mDahej 1.5-2.5 m 3-4.5 m 2-3 mHazira 2-3 m 3.5-5 m 2.5-3.5 m

(Source: Merh 1997)

4.3.4 Nature of tidal sediments

The grainsize variation of the suspended sedimentsis practically the same both spatially andtemporally. Mineralogically, these suspended

sediments are also similar to that of tidal flats.Table 4.10 and Fig. 4.7 show the clay mineralpercentage in the gulf suspended sediments.Montmorillonite, the major clay mineral in the gulfsuspended sediments, makes up about 75 to 85%of the total clay mineral assemblages, followed byillite (10-14%). The occurrence of chlorite andkaolinite is insignificant. The distribution of clayminerals in the gulf is homogeneous, suggestinga strong hydrodynamic condition in the gulf.

38


Fig 4.7 Minerology around Gulf of Khambhat

39


Table 4.10Clay mineralogical percentages in suspended sediments

Location Month/ Year

Montmorillonite, %

Illite, %

Chlorite, %

Kaolinite, %

Methla

April 85 July 95 October 85 January 86

75.99 78.96 77.77 80.97

13.93 11.69 13.23 10.56

05.98 05.20 04.40 04.65

04.10 04.15 04.60 03.82

Ghogha


75.90 82.05 76.55 83.12

14.28 10.25 13.66 10.23

05.01 03.89 04.80 03.55

04.81 03.80 04.99 03.10

Piram East


79.54 75.36 81.30 82.88

12.28 13.53 11.16 09.92

04.20 06.31 03.99 03.61

03.98 04.80 03.55 03.59

Khambhat


77.66 78.53 74.28 78.59

13.75 14.13 17.71 13.83

04.76 04.48 04.01 03.48

03.83 02.86 04.00 04.10

Dahej


73.27 79.74 77.88 75.98

18.30 11.96 13.21 15.17

04.23 04.20 04.50 05.16

04.20 04.10 04.41 03.69

Hazira


77.53 79.33 83.11 82.35

11.98 10.34 10.56 09.42

05.67 05.34 03.18 04.75

04.82 04.99 03.15 03.48

40


5

VEGETATION

Vegetation is one of the best indicators of theecological health of any given area by reflectingchanges in their structure (density, cover, etc.) anddistributional pattern. Further, by holding thelower most position of trophic level it supportsmany other life forms, including the human.However, with growing population, pressure onnatural vegetation has increased manifold inrecent years, which finally breeds various typesof environmental problems of different scales. Asimilar situation is, therefore, met with in andaround ASSBY. Keeping this in view, vegetation(especially of onshore areas) was considered asone of the important study components to achievethe objective of formulation of environmentalmanagement plan for ASSBY and surroundingareas.

The study was conducted in two different phases.In the first phase a floristic inventory wasprepared, while in the second phase, some detailedphyto-sociological studies were conducted.The Study was conducted in three steps. In thefirst step the changes in the vegetation patternover the years was assessed at macro level fromsatellite data. The second step was the preparationof floristic inventory, while in the third step somedetailed phyto-sociological studies wereconducted.

5.1 VEGETATION CHANGEDETECTION USING RS DATA

Remotely sensed (RS) satellite data of March 1985and January 1998 was used to assess the impactof ASSBY on the natural vegetation in the area.The RS data comprised of Landsat MSS for 1985(Plate 5.1) and IRS LISS III for 1998 (Plate 5.2).The slides (diapositives) of both of these data wereenlarged to 1:50,000 scale with the help of anequipment called 'Procom', and was interpretedwith reference to changes in the natural vegetationduring this periods.

A comparison of the landuse pattern between the

two periods (Fig. 5.1) shows that the direct impactof ASSBY on vegetation has been restricted onlyto the coastal belt where the land was used foragriculture or Prosopis plantation. Part of the areathat is occupied by ASSBY was previously a beachand the direct impact is restricted only to theregions of actual ship breaking and the houses ofthe workers. This actually means a change inlanduse pattern in a 200 m (average) wide belt ofabout 10 km length.

The situation beyond this belt along the coastlinehas mostly remained similar. At some of the placesthe thickness of Prosopis julliflora has increased.Further towards landside, certain changes havetaken place in the area, most of these changes arecaused by the increase in agriculture land. Almostall of the land that has been converted toagriculture was previously scrubland (in 1985).This comparison, therefore, reveals that ASSBYhas not caused the changes in vegetation structurebeyond its actual existence, and it is other factorsthat have resulted in the observed changes.

5.2 FLORISTIC COMPOSITION

5.2.1 Methodology

The floristic composition of Alang-Sosiya and itssurrounding areas have been studied duringSeptember 1996 to February 1997. The entire studyarea was divided into four blocks for the ease ofdocumentation and presentation of data (Fig. 5.2).They are:A. Block I: Alang - Sosiya with

surrounding mainlandsB. Block II: Mithivirdi including coastal

areas and mainlandC. Block III: Gopnath-Sartanpar coastal

area and the surroundingmainlands

D. Block IV: Bhandaria - Talaja belt

In each block a reconnaissance was made toidentify some areas for intensive documentationabout the flora. This followed an intensiveobservation of floral components at differenthabitats; for example,

41


Plate 5.1 & Plate 5.2

42


Fig. 5.1 Comparison of vegetaion in Assby region between 1985 & 1998

43


Fig 5.2 Categarisation of the study area for vegetation study.

44


streams and river banks, pond and puddle areas,protected grass lands, unprotected grazinggrounds, crop fields, hedges of the crop fields,plantation areas, road side plantation strips,orchids, coastal strips etc. The fieldwork includedidentification of plants on the spot andconfirmation of identification following Santapau(1962), Shah (1978), and Bole and Pathak (1988).Identification in laboratory was accomplished withthe help of recorded herbarium sheets and fromrecords of Cook (1901-08) and Bailey (1951).

The floral abundance has been rated subjectivelyas per the modified abundance scale (Pandya andPathak 1995).

5.2.2 Floral abundance

A total of 433 species of wild and cultivated plants,including 365 dicots and 68 monocots, wererecorded and identified from the four blocks of thestudy area (Table 5.1).

In all the four blocks, the species of Leguminosaefamily were dominant, followed by Poaceae andEuphorbiaceae (Table 5.2). Due to the presence ofrelatively high number of species (403 out of total433) in general, and of family leguminosae andpoaceae in particular, block IV seems to be morerich in floristic terms. However, comparativelyhigh ratio (0.78) of cultivated to wild plant species(Table 5.3) indicate more human activities in thisblock.

Blocks Dicotyledons Monocotyledons Total I-Alang-Sosiya 199 37 236 II-Mithivirdi 241 58 299 III-Gopnath-Saltanpar 276 57 333 IV-Bhandaria-Talaja belt 341 62 403 Overall 365 68 433

Table 5.1The Flora of Alang-Sosiya Complex and its surrounding

45


A total of 136 species (111 dicots and 25 monocots)were recorded commonly in all the four blocks.Floral analysis also reveals a fairly high number(109) of exotic species from the area. Avicenniamarina, was the only mangrove species observedat the coastal site of blocks II and III, with poorpopulation density.

5.2.2.1 Common wild andnaturalised plants

The species in the abundance scale of 3 and more,and occurring at the frequency of 30% and more,are considered here as common plants of the area.The common species are as follows:

A. Grasses:Apluda mutica, Aristida adscensionis,Cynodon dactylon, Dactyloctenium

aegyptium and Dichanthium annulatum

B. Herbaceous legumes and forbs:Alysicarpus vaginalis (Block III and IVonly), Goniogyna hirta, Rhynchosiaminima, Amaranthus spinosus, Boerhaviadiffusa, Borreria stricta, Convolvulusarvensis, Cyperus rotundus, Echinopsechinatus, Eclipta alba, Evolvulusalsinodes, Euphorbia hirta, Partheniumhysterophorus, Pulicaria whitiana,Trianthema portulacastrum, Tridexprocumbens, Vernonia cinerea.

S Families Total Distribution of species N. Species Block I Block II Block

III Block IV

1 Leguminosae 72 44 45 57 71 sub-families: -Papilionaceae 40 25 25 30 40 -Caesalpinaceae 17 10 11 15 16 -Mimosaceae 15 9 10 13 15

2 Poaceae 43 24 39 36 42 3 Euphorbiaceae 23 12 11 16 22 4 Convolvulaceae 18 13 11 10 15 5 Malvaceae 15 13 13 14 15 6 Asteraceae 15 10 12 14 15 7 Solanaceae 12 7 10 10 11 8 Cucurbitaceae 11 5 5 6 10 9 Amaranthaceae 10 6 8 9 10

10 Tiliaceae 9 7 8 7 9 11 Acanthaceae 9 9 8 9 8

Table 5.2 Dominant floral families in the four blocks

46


C. Under-shrubs:Achyranthes aspera, Pupalia lappacea,Tephorsia purpurea and Sida spinosa

D. Shrubs:Abutilon glaucum, Calotropis procera,Capparis decidua, C. sepiaria (in hedgesonly), Leptadenia reticulata (both in hedgesand grounds), Euphobia nerfolia andZizyphus nummularia.

E. Trees:Ailanthus excelsa, Acacia nilotica, Prosopiscineraria, P. juliflora, Salvadora persica.

Prosopis juliflora and Parthenium hysterophorusare exotic weeds occurring in wide areas of all thefour blocks (Plate 5.3).

S Plant-habit BlockI BlockII BlockIII BlockIV N Wild Cult. Wild Cult. Wild Cult. Wild Cult. 1 Herb-erect 51 14 79 21 87 25 96 34 -prostrate 37 01 44 02 41 01 46 03 -climber/twinner 11 02 09 04 10 04 13 05 Subtotal 99 17 132 27 138 30 155 42 2 .Undershrub-erect 20 01 21 05 28 05 30 10 -scandent 04 02 04 01 04 01 04 01 -climber 01 00 00 01 01 01 01 03 Subtotal 25 03 25 07 33 07 35 14 3 Shrub-erect 10 21 16 26 16 36 15 40 -scandent 03 03 04 02 08 00 07 03 -climber 09 03 08 01 09 04 08 07 Subtotal 22 27 28 29 33 40 30 50 4 Trees-small 02 16 03 22 06 27 06 42

-medium to large 01 24 01 25 01 28 01 28 Subtotal 03 40 04 47 07 45 07 70 Total plants species 149 87 189 110 211 122 227 176 Total of the block 236 299 333 403 (a) % of the wild species 63% 62% 63% 56% (b) % of the cult. species 36% 36.8% 36.6% 43.7% (c) ratio of cult. to wild species 0.58 0.58 0.58 0.78

Table 5.3Habitwise distribution of wild and cultivated (cult.) plant species in the fourblocks

47


5.2.2.2 Cultivated plant speciesThe distribution of major and minor cultivated cropspecies in the four study blocks is presented inTable 5.4.

Ground-nut, pearlmillet and sorghum are themajor Kharif crops and onion and garlic are the

Rabi crops of the study area. Sugarcane and bananaare also cultivated in areas covered by the Shetrunjiirrigation project.

A variety of tree/woody species have been observedalong the road side strips, avenues and gardens.The common species are Acacia

leucophloea, A. nilotica, A. tortalis, Azadirachtaindica, Cordia sp., Delonix elata, Leucaenaleucocephala, Mangifera indica, Moringa oleifera,Tamarindus indica, Prosopis juliflora andHoloptelia integrifolia.

Other species observed as plantation and avenuetrees are Albizia lebbeck, Cassia siamea, Delonixregia, Mimosa hamata and Pithecellobium dulce.The important horticultural woody speciesobserved are Cocos nucifera, Punicum granetum,Psidium guajava, Syzygium cumini and Terminaliacattapa. The details of topography, soil types, land-

use pattern and vegetational covers of the fourblocks are presented in Table 5.5.

5.3 PHYTOSOCIOLOGY

The main objective of this aspect of the study wasto evaluate the impact, if any, of ASSBY on coastalvegetation with special emphasis on onshorevegetation. For this, an intensive study wasundertaken after the monsoon showers of 1997 infour localities along the coastline, and at varyingdistances from ASSBY (Fig. 5.2). The stations are:

l S-ASSBY (upto 1 km from last ship-breaking plot on both sides)

l N-ASSBY (-do-)l N-Control (~ 3 km north of N-ASSBY)l Ghogha - extension of N-Control (~ 15 km

north of N-ASSBY)

Table 5.4 Cultivated crops in the Alang-Sosiya complex and itssurroundings

B lo c k s M a j o r - c r o p s M in o r - c r o p s A n n u a l c r o p K h a r i f R a b i K h a r i f R a b i

I - A la n g & S o s iy a

G r o u n d n u t + S o r g h u m +

O n io n + G a r l i c + w h e a t+

G r a m + C h i l l y +

C o t to n + P ig e o n p e a + B a n a n a + S u g a r c a n e +

I I - M i t h i -v i r d i

G ro u n d n u t+ ++ P e a r l -m i l l e t+ + S o r g h u m + M a iz e +

O n io n + + G a r l i c + W h e a t+

S esam u m+

M u s ta r d + G r a m + + S u n f lo w e r + C h i l l y + +

C o t to n + + + P ig e o n p e a + + B a n a n a + + S u g a r c a n e +

I I I - G o p n a th & S a r ta n p a r

G r o u n d n u t+ + P e a r l -m i l l e t+ + S o r g h u m + + M a iz e +

O n io n + + G a r l i c + W h e a t+

S esam u m+

G r a m + + C h i l l y +

C o t to n + + P ig e o n p e a + B a n a n a + + C a s to r s e e d + + S u g a r c a n e +

IV - B h a n d a r i y a to T a la ja b e l t

G ro u n d n u t+ ++ P ea rl-m il le t+ + S o rgh u m + + M a iz e+

O n io n + + G a r l i c + + W h e a t+ + C h i l l y + ++

S esam u m+

M u s ta r d + G r a m + + U d a d ( R ) M a g ( R ) S u n f lo w e r +

C o tto n + + + P ig eo n p ea+ + B an an a+ + C asto rseed + ++ S u g a rcan e+

48


Plate 5.3 Thickets of Prosopis around ASSBY

49


5.3.1 Sampling

The vegetation of the area was studied in twophases at different times. During the first phase areconnaissance was conducted in the areas aroundthe ASSBY- the disturbed site; Ghogha - anundisturbed site and the influence zone along theroad between ASSBY and Bhavnagar. This surveyhelped in finalising the methodology for intensivesampling to determine the phytosociological valuesand the impacts of ASSBY activities on vegetation.

A stratified random sampling was adopted to studythe vegetation. Stratification was based on thelocalities and distance from ASSBY. The on-siterandom sampling was done by walking 50 pacesin the direction of the second's hand of the wristwatch.

5.3.2 Data collection

A 10m radius circular plot was used to quantifythe tree and large shrub species and their seedlings/saplings. Individuals of a tree/shrub species werecounted in the plot. In case of trees, the Girth atBreast Height (GBH) was also measured. Withinthis 10m radius plot, five 0.5X0.5 sq. m quadrateswere selected randomly by tossing pebbles. Smallshrubs, herbs and grass species were recorded andtheir percentage cover was estimated in thesequadrates.

A total of 21 circular plots and 105 quadrates werelaid in the four sites at S-ASSBY, N-ASSBY,Ghogha and N-Control. A total of 22 plant specieswere recorded. The specimens were identified atthe Botany department of M.S University ofBaroda.

5.3.3 Data analysis

Tree seedling and large shrub density wascalculated according to sample stations and theirgroup means were compared. The significance ofdifference among means were statisticallydetermined using non-parametric tests (Kruskal-Wallis test). The large sample size in most of the

cases ensured robustness of the results even usingnon-parametric statistics. The minimumprobability of accepting the differences in groupsmeans was set at 95% confidence level, i.e.,probability of rejecting the results, P< 0.05.Similarity indices were calculated followingMueller-Dombois & Ellenberg (1974). Theequation for similarity index is as follows:

ISE = Mc/2 X 100Ma+Mb+Mc/2

Where,Ma = sum of density/cover of species

unique to site aMb = sum of density/cover of species

unique to site bMc = sum of density/cover of species

common to both sites a and b.

A division of Mc by 2 is done because the commonspecies represent two sets (sites) of values whenthere density/cover are used, but in terms ofpresence they represent only a single set.

5.3.4 Trees

Total tree species recorded in all sites were three,viz., Acacia leucophloea and Azardiacta indica atN-Control, and Avicennia marina at Ghogha.Except the first, others were seedlings/saplings.Only one individual of A. leucophloea wasrecorded. This suggests low density, and highlyrestricted distribution of trees in the area.

Seedling/sapling of A. marina were found in largenumber at Ghogha coast. However, distribution ofthis mangrove species was limited and patchy (Fig.5.3).

5.3.5 Shrubs

Six shrub species were recorded in the area (Table5.6 & 5.7) three of which (Calotropis, Prosopisjulliflora and Zizyphus nummularia) were mediumto large size and others were small.Among the medium to large shrubs, the maximumfrequency was that of P. julliflora (Table 5.6) andminimum was of Zizyphus nummularia. P.

50

Eco

logica

l Resto

ratio

n a

nd P

lannin

g fo

rA

lan

g-S

osiya

Sh

ip-B

rea

king

Yard

, Gu

jara

t

Table 5.5 Site Characteristics of Alang-Sosiya complex and its surroundings

Blocks Sea-shore Main-land Topography Soil Land-use Vegetation Topography Soil Land-use V

I - Alang & Sosya

Plain, rocky at places

Sandy, to sandy loam

Crop-fields, fruit-gardens (horticulture)

Grasses, some scattered shrubs tree mostly absent except those planted

Plain to undulating

Medium black, clayey loam

Mostly crop fields, undulating grass-lands with seasonal / perennial climbers & scandent shrubs

Grasses anscattered ssmall trees

II - Mithivirdi

Sandy coast with rocky inter-tidal zone

Sandy and sand mounts

Grassland, crop-fields horticultural fields

Mostly grasses with succulent shrubs, planted Prosopis chilensis in bushes; some muddy area on sea-coast with highly scattered seedlings & saplings of mangroves

Undulating area interrupted by some plain and low-lying areas

Light morrum in undulating area, medium black in depression & plain area

Crop fields in low-lying plain grasslands in hilly upland and grazing in undulating area

Grassland sp. undulafodder grascattered bnummularlocations, Peither abseand growth

III - (a) Sartanpar (b)Gopnath

(a) Plain (b)Rocky sea shore

(a) Silty loam with deep alluvial dipos at places (b)sandy silty loam

(a) Crop-fields (b)Crop-fields

(a) Mostly Undershrubs & shrubs scattered as small bushes and forbs (b) Muddy shore with scattered mangroves

(a) Plain, some low-lying water-logged areas (b) salty marshes

Clayey loam in crop fields, to sandy silty loam in low- lying & marshy area

Crop-fields; grazing in low-lying and water-logged area

Water-logsedges andmarshes andominatedbush formthickets

IV - (a) Bhandariya to (b) Talaja belt

(a) Plain to Undulating (b) mostly plain

(a)Light to medium black and silty loam (b)medium black-clayey

(a)Crop-fields grazing grounds (b) Crop-fields

Scattered bchilensis, ZMaytenus some grass

51


julliflora was recorded in each plot at S-ASSBYand its frequency of occurrence was 50% at N-ASSBY and N-Control. The relatively higherfrequency of this species at S-ASSBY was due tothe location of the sampling strip at relativelyundisturbed site. The site at N-Control was underheavy cutting pressure. The strata at both the sides

of S-ASSBY-N-ASSBY road was different.

The density of medium to large shrubs ranged from31.8 to 764.3 individuals (or bunch) per hectarein all the sites. It was maximum at S-ASSBY and

N-ASSBY (Fig. 5.4) and minimum at N-Control.The overall difference was significant statistically(K-W c2 = 7.78, degree of freedom = 3, P = 0.05).An ocular estimate at Ghogha suggested that theshrub density would be similar to N-Control. Thecomparatively low shrub density at N-Control wasdue to cutting down of P. juliflora (the largest

contributor to the shrub density; Table 5.7) asfuelwood which was supported by focalobservations.The frequency of occurrence of small shrubs/herbswhich had just sprouted up was relatively poor atS-ASSBY and N-ASSBY (Table 5.8), and betterat N-Control.The maximum frequency at which a small shrub/

Table 5.6 Absolute frequency (AF) and Relative frequency (RF) of large shrubsspecies

Large Shrub Density Species S-ASSBY N-ASSBY N-Control

AD RD AD RD AD RD Calotropis sp. 83.3 45.5 16.6 20.1 0 0 Prosopis julliflora 100.0 54.5 50.0 59.8 50.0 50.0 Zizyphus nummularia 0 0 16.6 20.1 50.0 50.0

Shrub Density Species S-ASSBY N-ASSBY N-Control Average

AD RD AD RD AD RD AD RD Calotropis sp. 79.6 22.3 10.6 4.2 0 0 31.4 13.7 Prosopis julliflora 276.6 77.6 212.3 85.1 47.7 40.0 173.6 75.5 Zizyphus nummularia 0 0 26.5 10.6 71.6 60.0 24.8 10.8

Table 5.7 Absolute density/ha (AD) and Relative density (RD in %) of largeshrubs species Shrub Density

52


0

500

1000

1500

Ghogha

(extensi on of

N -Control )

N -A SSBY S-A SSBY

De

nsi

ty/

h Low

A vg.

H igh

Fig 5.3 Avicennia maina seedling density at various localities on coast.

Fig 5.4. Shrub density at various localities on coast.

0

200

400

600

800

S-A SSBY N -A SSBY N -Control

Sh

rub

De

nsi

ty Low

A vg.

H igh

53


herb was recorded was 30% in case of Boerhaviadiffusa.

Similar pattern was observed for the percentageof cover provided by small shrubs/herbs where B.diffusa also dominates (Table 5.9). Shrub coverwas maximum at N-Control (K-W c2 = 56.31,degree of freedom = 3, P = 0.0000) and minimum

grass both in terms of frequency (Table 5.10) andcover (Table 5.11), followed by Cenchrus ciliaris.The average grass cover was maximum at N-Control and minimum at N-ASSBY (K-W c2 =28.81, degree of freedom = 3, P = 0.0000), (Fig.5.6).

at S-ASSBY and N-ASSBY (Fig. 5.5). Theincreased shrub cover at N-Control could be dueto favourable substratum and increased input oforganic fertiliser such as, dung. The substrata atS-ASSBY and N-ASSBY are sandy withinsignificant humus content.

5.3.6Grass

Desmostchaya bipinnata was the most dominating

5.3.7 Similarity index

Similarity index (Mueller-Domboys and Ellenberg,

Table 5.9 Absolute cover (AC) and Relative cover (RC) of small shrubs species% Small Shrub Cover

Table 5.8 Absolute frequency (AF) and Relative frequency (RF) of small shrubsspecies Small Shrub Frequency

Small Shrub Frequency Species S-ASSBY N-ASSBY N-Control

AC RC AC RC AC RC Boerhavia diffusa 0 0 10 100 30 52.6 Indigofera enneaphylla 0 0 0 0 17 29.8 Tridex procumbens 6 100 0 0 10 17.6

% Small Shrub Cover Species S-ASSBY N-ASSBY N-Control

AC RC AC RC AC RC Boerhavia diffusa 0 0 0.1 100 6.3 62.4 Indigofera enneaphylla 0 0 0 0 2.1 20.8 Tridex procumbens 0.06 100 0 0 1.7 16.8

54


0

5

10

15

20

25

30

S-A SSBY N -A SSB Y N -Control

% S

hrub

Cov

er Low

A vg.

H igh

Fig 5.5 Percentage of shrub cover at various localities on coast.

0

20

40

60

80

S-A SSBY N -A SSBY N -Contr ol

% G

rass

C

over

Low

A vg.

H igh

Fig 5.6 Percentage of grass cover at various localities on coast.

55


Table 5.10 Absolute frequency (AF) and Relative frequency (RF) ofgrass species

Table 5.11 Absolute cover (AC) and Relative cover (RC) of grass species

* A. lagopoides was recorded only from Ghogha (extension of N-Control). It had an absolute 2.96%cover of and relative cover was 100%.

* A. lagopoides was recorded only from Ghogha (extension of N-Control). It had an absolute frequencyof 33% and relative frequency was 100.

% Grass Cover Species S-ASSBY N-ASSBY N-Control

AC RC AC RC AC RC Aleuropus lagopoides* 0 0 0 0 0 0 Cenchrus ciliaris 0 0 1.93 65.9 3.8 22.6 Commalina nodiflora 0 0 0.20 6.8 0 0 Cyperus rotundus 0 0 0 0 0.75 4.5 Desmostachya bipinnata 2.83 78.6 0 0 12.25 72.9 Scirpus asticulatus 0.77 21.4 0 0 0 0 Unidentified 0 0 0.80 27.3 0 0

% Grass Frequency Species S-ASSBY N-ASSBY N-Control

AF RF AF RF AF RF Aleuropus lagopoides 0 0 0 0 0 0 Cenchrus ciliaris 0 0 40 54.1 30 39.0 Commalina nodiflora 0 0 7 9.5 0 0 Cyperus rotundus 0 0 0 0 7 9.1 Desmostachya bipinnata 43 61.4 0 0 40 51.9 Scirpus asticulatus 27 38.6 0 0 0 0 Unidentified 0 0 27 36.5 0 0

56


1974) shows that the vegetation of S-ASSBY andN-ASSBY was mostly similar (69%) while therewas about 50% similarity between the vegetationof S-ASSBY and N-Control (Table 5.12).Although, the similarity of vegetation between S-ASSBY and N-ASSBY is almost 17% more thanthat between S-ASSBY and N-Control, thedifference is not much and is due to the differencein the substratum. The anthrogenic factors havenot played significant role in altering thecomposition of vegetation as is evident by the factthat the vegetation of N-ASSBY and N-Controlwas 63% similar.

Table 5.12 Similarity of vegetationbetween different sites

5.4 CONCLUSION

The detail of floristic composition indicates thatblock I, which includes ASSBY, is relatively poorerin plant species compared to other blocks. BlockIV represents the rich species zone in the studyarea. Herbs are less in block I relative to otherblocks. Wild tree species are rich in block III andIV. The cultivated plant species also show aprogressive increment from block I towards blockIV (Table 5.3). The cultivated plant speciescomprises of 58% of the total plant species in blockI, II and III, which increases to 78% in block IV.This indicates a progressive pressure on naturalvegetation in block I, II and III.

On the other hand, quantitative studies in differentlocalities indicate that the variation in speciescomposition and abundance does not have anycorrelation with ASSBY activities. Instead, it isthe variation in substratum, type of shore andactivities of villagers that have caused differencesin the species composition and abundance at thethree sites. In short, ASSBY activities beingprimarily confined to off-shore and intertidalregion, coupled with the fact that the region isunder pressure from other anthropogenic activities,no significant impact on on-shore vegetation wasobserved.

Sites S-ASSBY N-ASSBY N-ASSBY 69% N-Control 51.7% 63%

57


6

INTERTIDAL ECOLOGY

The intertidal zone or littoral zone is a shore arealying between the extremes of high and low tides,and thus represents the transitional area betweenmarine and terrestrial conditions. However, it isemphasised that this area is truly an extension ofmarine environment and thus been affected bydifferent physico-chemical-biological factors ofmarine environment. Further, since it was mostaccessible to humans for study purpose, it has beena constant source of information in betterunderstanding and management of coastal marineenvironment.

Zonation is a characteristic feature of the intertidalregion, which can be divided into certain welldesigned sub-zones depending on the tide levels.Stephenson (1953) recognised three universalzones for intertidal regions which are as follows:

a) Supra littoral zone (upper intertidal zone)b) Mid-littoral zone (middle intertidal zone)c) Infra littoral zone (lower intertidal zone)

In shores, where the tidal range is small, theintertidal zone is narrow and therefore, thezonation is not very distinct, whereas in shoreshaving a wide tidal range like gulf of Cambay, thezones are correspondingly wide and quite distinctvertically.

Organisms of the intertidal zone are adapted invarious ways to transitional environmentalconditions. Physio-chemical factors like waves,nutrients, salinity, insolation and temperature havegreater influence on otherwise densely populatedbiotic communities of the intertidal region. Theavailability of organic matter and, nutrients, mostlyderived from the disintegration of animals andplant materials; adequate oxygenation andillumination ensure an abundance of life forms inthe intertidal region. Also, the nature andcomposition of the fauna and flora of the intertidalzone depend on the nature of the substratum,whether it is rocky, sandy or muddy.

6.1 METHODOLOGY

To understand the ecology of the intertidal zone,various physio-chemical parameters of water aswell as sediments and abundance and diversity inmacrobenthic fauna were evaluated. Specialattempt has also been made to collect informationregarding the oil related micro-organisms.

The study was undertaken in the region betweenthe highest high tide mark and the lowest low tidelevel (eulittoral zone). A total of five transects weremarked for this study. Two transects, representingcontrol sites were selected at the north and southends of ASSBY near Ghoga-Mithivirdi andGopnath-Mahuva respectively, hereafter referredas N-Control and S-Control. For sampling theASSBY area, three transects were selected at thenorth, middle and south part of ASSBY nearSosiya; Plot Nos. 1-15 and 30-40, and Sartanpar,hereafter reffered as N-ASSBY, M-ASSBY and S-ASSBY, respectively. However, M-ASSBY was leftout from the study on macrobenthic community.The nature of the substratum at the samplinglocations were as under:

N-Control

The intertidal area at this location consisted ofdepositional landforms mainly beach and duneridge complex. The sediments were mainly clayeyin nature with small contents of silt and sand. Fromthe high water line to 800 m, the sediment waspredominantly clay and silt with frequent layersof well rounded medium to fine grain sand whilebeyond 800 m towards the sea, it waspredominantly clay and silt. At some places, theupper intertidal area was rocky followed by a smallstretch extending to the lower intertidal region.

N-ASSBY

The 1-5 km long intertidal platform, which markedan erosional feature of wave action was seen as avery gently sloping rocky and sandy plane, togetherwith some muddy patches. The beach sedimentvaried from very fine sand to very coarse pebblygravels in upper intertidal zone interspersed byrocky patches while the lower intertidal area was

58


predominantly muddy.

S-ASSBY

The intertidal platform had a very gentle seawardslope of rocky muddy and sandy plane. The tidalexposure was about 2 km from the highest highwater line, of which first 200 m was completelyrocky. The area above lowest high water line wassandy with very coarse gravel. The rocks weregenerally covered with deposition of fine clay andother wastes.

S-Control

The upper intertidal platform in this area was rockywith silt and clayey patches in between. The lowerpart of the intertidal area was rocky but coveredwith fine grain mud. The uppermost intertidalregion was sandy with rocky cliffs.

6.1.1 Sampling

The sediment and water samples were collectedand analysed following standard methods (APHA,1980).

For macrobenthic study, sampling was separatelyplanned for soft (muddy and sandy) and rockysubstrata. Four transects namely Ghogha (N-Control), Sosiya (N-ASSBY), Alang (S-ASSBY)and Gopnath (S-control) were selected for thisstudy. Among them S-ASSBY and N-ASSBY werepresumed as affected sites while N-control and S-control were presumed as control locations. Whilefor soft surface these transects were divided intolower, middle and upper intertidal zones; for rockysurface the transects were divided only into upperand lower-intertidal zones. In each transect,macrobenthic fauna were sampled from a total 10stations form these different zones.

Sediment samples were collected using a quadrateof 0.25 m2, 1 sq. ft and 2 cm2 for rocky, muddyand sandy intertidal regions respectively. Thesediments were sieved through a 0.5 mm meshsieve and materials retained on the sieve waspreserved in 5% formaldehyde-rosebengalsolution. For rock-associated fauna, organisms

were directly picked up from known area (1 sq. ft- 0.2 cm2) depending upon the species andpopulation of macrofauna.

6.1.2 Data Analysis

Population counting of macrobenthos was donefollowing methods suggested by UNESCO (1968)and IOBC (1969). In the laboratory, the sampleswere screened under a binocular stereo microscopeand organisms were identified, sorted out, countedand preserved separately in small plastic containers(Holme and McIntyne, 1984). The number ofmacrobenthic animals present was calculated byusing the following formula:

No/m2 =

No. of animals present in1 sq ft sample X 11

No. of sq ft sample collected

Biomass of macrobenthic organisms was estimatedon fresh weight basis. Each group of animals weresorted out and adhered water content was removedusing blotting papers and finally weighed on ananalytical balance. Shells of molluscs wereremoved before weighing.

Diversity and Similarity index were estimated assuggested by Magurran (1988). Taxa richness andShannon-Wiener group diversity index were usedto estimate diversity of macrobenthic fauna. ForShannon-Wiener Index (H') was calculated usingfollowing formula:

H' = - pi log pi

Where, pi = the proportion of individuals ofdifferent species groups.

For Similarity index Jaccard and Sorenson indexwere calculated using following formulae:

c a = Total no of taxa at site 1J = -----------------

a + b - c b = Total no of taxa at site 2

2cS = --------------- c = No of taxa common to

a + b site 1 & 2

59


6.2 PHYSICO-CHEMICALPROPERTIES OF WATER

6.2.1 Salinity, pH and DissolvedOxygen (DO)

The salinity at and around the ASSBY showedvery little spatial and seasonal variations (Fig. 6.1)The salinity in the ASSBY areas showed aminimum value of 29.7 ppt in M-ASSBY duringpre-monsoon season. However, during the sameseason the maximum value of 31.0 ppt wasrecorded from S-ASSBY. However, these valueswere comparatively lower than the controltransects, where the maximum salinity of 33.1 pptwas recorded from the S-Control. The low salinityreflects the semi-estuarine condition of the studyarea.

The pH was always in alkaline range at and aroundASSBY and varied between 7.86 to 8.16 (Fig. 6.2).The seasonal variation in pH was not significantin the study area. However, at ASSBY pH wascomparatively low and high during the pre-monsoon and post-monsoon seasons, respectively.DO content also showed a narrow range ofvariation amongst the transects and seasons (Fig.6.3). However, at ASSBY the higher DO contentwas recorded during the winter season.

6.2.2 BOD, COD, and Oil-PHC

Wide spatial as well as seasonal variations inconcentration of BOD, COD and oil-PHC wererecorded during the study (Fig. 6.4, 6.5 & 6.6).The value of these parameters were recorded higherin the transects at ASSBY as compared to thecontrol transects. This suggests higher organic loadin the littoral zone of ASSBY. Further, in the N-ASSBY and M-ASSBY, BOD, COD and Oil-PHCwere recorded lowest and highest values duringthe post- and pre-monsoon seasons, respectively.However, in S-ASSBY the parameters recordedno such seasonal variation.

6.2.3 Dissolved phosphorus andnitrogen

Phosphorus was determined as PO4- whileNitrogen was determined as NH4+, NO3-, NO2 -and total-N, There was a very little difference inthe values of PO4-P within a transect at differentseasons. However, S-Control recorded lowerconcentration of PO4 (Fig. 6.7) than the other sites.No significant seasonal or spatial variation wasrecorded in the concentration of various species ofnitrogen (Fig. 6.8 to 6.11). The range of variationof all species of N in transects at ASSBY arecomparable with the transects at control areas.While S-Control recorded relatively lowerconcentration of total-N, NH4-N and NO2-N; theN-Control recorded the highest (41.5 µg/l)concentration of NO3-N during the winter season(Fig. 6.10).

60


29

.4 30.1

30

.3

30

.2

30

.731.9

30

.8

30

.7

30.6

32

.3

31

.0

30

.8

29.7

31

.0

33.1

25 .0

27 .0

29 .0

31 .0

33 .0

35 .0

37 .0

N-Co nt rol N-A S S B Y M -A S SB Y S -A S S B Y S -C on tro l

pp

t

P os t-m ons oon

W in ter

P re-m ons o on

Fig 6.1 Salinity variation of water in intertidal zone.

Fig 6.3 DO variation of water in intertidal zone

7.9

8.1 8.

2

8.1

8.08.0

8.0

8.0

7.9

7.9

8.0

7.9

7.9

7.9 7.9

7. 5

7. 8

8. 0

8. 3

8. 5

N-Co n tro l N -AS S B Y M-A SS B Y S -A S S B Y S -Co nt rol

P ost-m onso on

W inte r

P re -m ons oo n

Fig 6.2 pH variation of water in intertidal zone.

5.8

5.2 5

.3 5.4

5.7

5.1

5.5

5.4

5.3

5.6

5.2

5.1

5.3

5.2

5.5

4.5

5.0

5.5

6.0

6.5

N-Co n tro l N-A S S BY M -A S SB Y S -A S S BY S -Co n tro l

mg/

l

P os t-m on s oon

W in ter

P re-m ons oon

61


Fig 6.6 Oil-PHC variation of water in intertidal zone

Fig 6.4 BOD variation of water in intertidal zone

5

.0

2.1 3.1

8.7

7.2

5.0

10.

9

10.

7

23.

7

5.2

0.0

5.0

10.0

15.0

20.0

25.0

30.0

N-C ontrol N-ASSBY M-ASSBY S-ASSBY S-C ontro l

mg

/l

Post-m onsoon

W inter

Pre-mons oon

26

.3

11

.0 16

.3

83

.6

3.3

14

.2 19.1

72.8

30.9

98

.0

29.0

0

20

40

60

80

10 0

12 0

N -Co ntrol N-A S S BY M -A S SB Y S -A S S BY S -Co n tro l

mg/

l

P os t-m o ns oon

W in te r

P re-m on soon

15.4

4.3 9

.9

17.9

21.1

20

.4

23

.227

.3

56.8

18

.2

5.4

0

10

20

30

40

50

60

N-C ontrol N-ASSBY M-ASSBY S-ASSBY S-C on trol

mg

/l

Post -Mons oon

W inter

Pre-m ons oon

Fig 6.5 COD variation of water in intertidal zone

62


Fig 6.9 NH4-N variation of water in intertidal zone

Fig 6.8 Total N variation of water in intertidal zone

Fig 6.7 PO4-P variation of water in intertidal zone

11

.7

15

.2

15

.6 17

.4

12.5

16

.1

12

.8

11.3

10

.7

8.6

15.5

13

.8

18

.2

16.3

9.5

0

5

10

15

20

25

N-Co nt rol N-AS S B Y M -A SS B Y S -A S S B Y S -C on tro l

mg/

l

P ost -m ons oon

W int er

P re -m ons oon

19

.2

17

.4

14

.1 16

.1

10

.8

22

.4

17

.3

16.4

15.0

8.3

22.1

11.5

12

.4

16

.0

9.4

0

5

10

15

20

25

30

N-C on tro l N -AS S B Y M -A SS B Y S -A S S B Y S -Co ntrol

mg/

l

P os t-m o ns oon

W in te r

P re-m on so on

9.2

19.9

19

.8

17

.0

1.9

11

.6 13

.7

9.6

14

.0

4.1

17.0

5.4

11.5

8.4

5.0

0

10

20

30

40

50

N-Co n tro l N-AS S B Y M -A S SB Y S -AS S B Y S -Con tro l

µg

/l

P os t-m o ns oon

W in te r

P re-m on so on

63


Fig 6.10 NO3-N variation of water in intertidal zone

Fig 6.11 NO2-N variation of water in intertidal zone

13.

7

13

.9

13.

5

13

.5 19.2

41.5

19.

1 24.5

12.

8

14.319

.9

12.

3 16.1

12.

8 18.8

0

1 0

2 0

3 0

4 0

5 0

N -Co ntrol N-A SS B Y M -AS S BY S -A SS B Y S -Co ntrol

µg/

l

P o st-m on so o n

W inte r

P re -m o ns oo n

14

.4

11

.9

12

.4

12

.1

7.08

.9

13

.6 17

.8

8.5

4.5

14

.4

11

.9

12

.4

12

.1

7.0

0

10

20

30

40

50

N-C on trol N-ASSBY M-ASSBY S-ASSBY S-C on trol

µg

/l

Post -monsoon

W inter

Pre-m ons oon

64


6.3 PHYSICO-CHEMICALPROPERTIES OF SEDIMENTS

6.3.1 Particulate nitrogen andphosphorus

The sediments in and around ASSBY haverecorded high nitrogen content. Total-N wasranging between 188 to 438 mg/kg at S-ASSBY,128 to 568 mg/kg at N-ASSBY, 14 to 134 mg/kgat S-Control, 12 mg/kg at Mahuva and 10 mg/kgat N-Control. The phosphorus concentration atdifferent transects have also followed the similartrend as of nitrogen. Phosphorus varies inconcentration between 35 and 188 µg/kg at S-ASSBY, between 53 and 113 µg/kg at N-ASSBY,16 to 46 µg/kg at S-Control and 18 µg/kg at N-Control.

6.3.2 pH and oil-PHC

The pH of sediment was alkaline in the study areaand varies from 7.72 to 8.3. The oil-PHC contentvaries from 10 to 450 mg/kg in the sediments ofASSBY; while it was below detectable level at thecontrol points.

6.4 MACROBENTHICCOMMUNITY

For the clarity and better understanding, the dataon macrobenthic community, e.g., speciescomposition, population, biomass and diversity,were separately evaluated for soft and rockysubstrates in each transects. Further, the data onmacrobenthos were also analysed and presentedfor three intertidal zones viz. upper, middle andlower intertidal zones. Suitable comparisons weremade wherever possible for each study parameters.

6.4.1 Macrobenthos on soft substrates

6.4.1.1 Population

Total macrobenthic population showed a wide

variation amongst the four transects (Fig. 6.12).Total as well as average population densities inboth the ASSBY transects (viz. N-ASSBY and S-ASSBY) were recorded significantly lower thanthe control transects, especially when comparisonwere made of N-ASSBY with N-Control and S-ASSBY with S-Control. Furthermore, under thesimilar mode of comparison (i.e. N-ASSBY withN-Control and S-ASSBY with S-Control), onlythe lower intertidal zones recorded near equalpopulation density of macrobenthos and, middleand upper intertidal zones recorded significantvariations. These variations thus highlight verypatchy presence of suitable habitats formacrobenthic population, especially in the upperand middle intertidal zones of ASSBY areas,possibly due to the direct disturbances caused byship breaking activities.

65


Fig 6.12 Population of macrobenthic community.

The next step of analysis of macrobenthicpopulation reflects that while molluscans, andparticularly Gastropod velligers, dominated thepopulation in N-Control and S-ASSBY transects(Table 6.1); polychaetes dominated in N-ASSBYand S-Control transects. However, crustaceanswere recorded in comparatively higher number inS-Control transect. Results also highlight that therewas no stratification of species group in threedifferent intertidal zones, except that thepopulation of Gastropod velligers in N-Controltransect recorded maximum number in upperintertidal zone (11752 No./m2) and lowest (1601No./m2) in low-intertidal zone (Table 6.1). Thisagain suggested very patchy distribution of evendifferent species group.

12731202576470268103

14522629

8327 1071

6163201

14186

0

8000

16000

24000

32000

N-Control N-ASSBY S-ASSBY S-Control

No/

sq m

Upper Inter tidal

Middle Intertdal

Low er Intertidal

66


Groups N-Control N-ASSBY S-ASSBY S-Control UIT MIT LIT UIT MIT LIT UIT MIT LIT UIT MIT LIT Crustaceans Amphipods 44 7 - - - 14 15 11 3 198 136 132 Isopods - - 3 29 - - - - - - - - Crab 4 18 8 59 235 3 11 11 - 51 7 14 Hermit crab - 18 6 - - - - - 4 - 6 Prawn (small) 136 18 25 - - - 15 37 41 15 26 58 Insect - 7 - - - - - - - - - Decapods - - - - - - - - - - - 6 Barnacles - - - - - - - - - 7 - - Molluscans Gastropod velliger

11753 7187 1601 62 224 74 15 1247 825 - 231 168

Bivalve - 37 17 4 - - - - - - 73 127 Onchidium 220 - - - - - - - - 11 - - Oyster - - - - - - - - - 26 18 - Chitons - - - - - - - - - 51 - - Fish small 4 7 22 - - - 4 26 36 - - - Polychaetes 1837 1027 5343 3047 2171 5673 495 114 275 194 6992 756 Nematodes 209 3 - - - 18 4 - - - - Others Cumaceans - - - - - - 40 - 14 - - 3 Copepods - - - - - - 4 - 3 - - - Pycnogonida - - - - - - - 4 6 - - - Cerithrids - - - - - - - - - 367 598 6 Calliostoma sp - - - - - - - - - 172 22 - Total 14206 8327 7026 150 458 91 616 1452 1202 1096 8103 1273

Table 6.1 Average Intertidal macrobenthic population (no/sq m) for selfabstracts.

67


6.4.1.2 Biomass

Like the population density, the biomass ofmacrobenthic communities also recorded a widevariation amongst the four transects (Fig 6.13).The total and average biomass in the controltransects were recorded significantly higher thanthe two transects in ASSBY areas. While thehighest biomass (151.9 gm/m2) was recorded fromthe lower intertidal zone of N-Control transect,the lowest biomass (3.4 g/m2) was recorded fromthe middle intertidal zone of S-ASSBY transect.However, no clear pattern of biomass was recordedin three different intertidal zones (Fig. 6.13). Thevariation in biomass, in this particular case, seemsto be controlled by the different proportion ofspecies groups present in the transects and differentintertidal zones (Fig. 6.14).

6.4.1.3 Diversity

The diversity in macrobenthic fauna was estimatedin terms of richness of taxa and Shannon-Wienerdiversity index of macrobenthic groups. Taxarichness was recorded maximum in S-Control andminimum in N-ASSBY transects (Fig. 6.15).Amongst the three intertidal zones across the fourtransects, the highest taxa richness (11) wasrecorded in the upper intertidal zone of S-Controltransect and lowest (3) was recorded from themiddle zone of N-ASSBY transect. However, therewas no clear pattern in taxa richness in threeintertidal zones. Maximum diversity (Shannon-Wiener index) was also recorded the in S-Controltransect and minimum in N-ASSBY transect (Fig6.16). However, in general the diversity wasrecorded very low in all the transects and theirespective intertidal zones. Comparatively low taxarichness and group diversity in the ASSBY areathan the control ones, suggested the high level ofhuman related interferences, mainly the pollution,in the area. While it was recorded that there wasno significant variation in term of diversity, it wasimportant to understand the level of similarityamongst the four transects, in terms of theirmacrobenthic communities. Two indices, Jaccardand Sorenson, were measured using presence/absence data of macrobenthos.

The two control transects (N-Control and S-Control) recorded the lowest similarity by both

Jaccard (0.27) and Sorenson (0.44) indices (Table6.2). The two northern most transects (N-Controland N-ASSBY), however, recorded the highestsimilarity in macrobenthic fauna as indicated byboth Jaccard (0.50) and Sorenson (0.67) indices.N-Control also recorded high level of similaritywith S-ASSBY (Table 6.2).

68


Fig 6.14 Species groups in different intertidal zones with different proportions.

Uppe r In ter- t ida l

0

20 00

40 00

60 00

80 00

1 00 00

1 20 00

1 40 00

N-Co ntro l N-AS S B Y S -AS S B Y S -Co ntro l

no

/sq

m

C ru s ta ce an s

Mo llus can s

P oly ch ae tes

oth ers

Midd le Ine r-tid al

0

200 0

400 0

600 0

800 0

1 000 0

1 200 0

N-C o ntro l N-AS S B Y S -AS S B Y S -C o ntro l

no

/sq

m

Lo we r In ter-t ida l

0

20 00

40 00

60 00

80 00

1 00 00

1 20 00

N-C on trol N-AS S B Y S -A S S B Y S -Co ntro l

no

/sq

m

Fig 6.13 Biomass of macrobenthic community.

16 .110 .45 .7

15 1. 9

38. 78 .918 .9

25. 8

79 .33 .44 .1

90 .5

0

50

100

150

200

250

300

N-Cont rol N-AS S BY S -A S S BY S -Con tro l

gm

/sq

m

Uppe r Inte r t idal

M iddle Int ert da l

Lo we r Inte rtida l

69


Fig 6.16 Diversity (Shannon-Wiener index) of macrobenthic community

Fig 6.15 Taxa richness of macrobenthic community

8

5

99

3

8

99

4

8

1011

0

2

4

6

8

10

12

N-C on tro l N-A S S B Y S -A S S B Y S -Co nt ro l

S

Uppe r Inte rti da l

M iddle Int ert id al

Lo we r Inte rti da l

0.6

0.2

0.9

1.8

0.5 0

.6 0.6

0.60.

6

0.1

0.9

1.3

0 .0

0 .2

0 .4

0 .6

0 .8

1 .0

1 .2

1 .4

1 .6

1 .8

2 .0

N-Con tro l N-AS S BY S -AS S B Y S -C on tro l

H

Upp er In ter tid a l

M idd le In te rtida l

Low er In ter tid a l

70


Table 6.2 Similarity index of macrobenthos in soft substratum

6.4.2 Macrobenthos on rockysubstrates

Of all the intertidal areas of the world, thosecomposed of hard material, the rocky shores, arethe most densely inhabited by macro-organismsand record higher diversity than the soft muddyand sandy shore types. Therefore, keeping this inview, these densely populated, species rich andtopographically diverse (microtopography) areaswere separately examined in detail. While in theN-Control transect only upper intertidal zone couldbe delineated, in the remaining three transects bothupper and lower intertidal zones were delineatedfor sampling.

6.4.2.1 Population

A total of 23 species were recorded from all thefour transects, of which the maximum number ofspecies (14) were represented by group Gastropoda(Table 6.3). Transect at S-Control recorded 20species, of which 11 were exclusive to this transect.While in comparison rest of the three transectsrecorded only 7-9 species with an unidentifiedspecies of each of Potamides and Balanus recordedexclusively in the N-Control and S-ASSBYtransects, respectively. Four species viz. Cerithiumscabridum, Cerithium morus, Calliostomascobinatum and Balanus amphitrite, were recordedfrom all the four transects (Table 6.3). Of thesespecies, however, Balanus amphitrite was recordedin abundance in all the transects. However, acrossthe transects, there was no significant variation inthe number of species in the upper and lowerintertidal zones (Fig. 6.17).

Stations N-Control N-ASSBY S-ASSBY S-Control N-Control 0.67 0.64 0.44 N-ASSBY 0.50 0.50 0.48 S-ASSBY 0.47 0.33 0.48 S-Control 0.27 0.31 0.32

Sorenson index Jacard index

Fig 6.17 Total number of species in the intertidal zone

65 5

9

3

16 16

0

6

12

18


Num

ber

of s

peci

es

Upper intertidal

Lower intertidal

71


The total population density was recordedmaximum in S-Control (96392 No./m2) andminimum in N-Control (14392 No./m2) transects(Fig. 6.18). Amongst the two ASSBY transects,N-ASSBY recorded higher density (34494 No./m2) than S-ASSBY (10308 No./m2). Furthermore,only in the N-ASSBY and S-Control transects,lower intertidal zones recorded higher populationdensity than upper intertidal zones (Fig. 6.18).Amongst the species groups, Barnacle recordedhigher density in all the transects with the

Table 6.3 Species abundance of rocky intertidal macrofauna at sampling sites

maximum value (42218 No./m2) in the lowerintertidal zone of S-Control transect (Table 6.4).Oysters were also recorded in high density in S-Control transect. Record of higher species richnessand population density in S-Control transect andthe low population density and species richness inS-ASSBY indicate that the latter has highlydisturbed shoreline.

N-Control

N-ASSBY S-ASSBY S-Control

UI LI UI LI UI LI UI LI Gastropoda Cerithium scabridum C -- C C C - A A Cerithium morus R -- -- R R - C C Astrea semicostalis -- -- -- -- -- -- -- A Calliostoma scobinatum C -- C C C R A A Clavatula Virginia -- -- -- -- -- -- C C Clavus Preclara -- -- -- -- -- -- -- R Nassarius ornatus -- -- -- -- -- -- -- R Cantharus spiralis -- -- -- R -- -- C R Diodora ticaonica -- -- -- -- -- -- R -- Haminoae galba -- -- -- -- -- -- R R Trochus sp. -- -- -- R -- -- R R Drupa subnodulosa -- -- R R -- -- C -- Planaxis acutus R -- -- R -- -- -- -- Potamides sp. R -- -- -- -- -- -- -- Cirripedes -- -- -- -- -- -- -- -- Balanus amphitrite A -- A A A -- A A Balanus sp. -- -- -- -- -- A -- -- Pelecypoda Crassostrae sp. C -- -- -- -- R A A Donax sp. -- -- R R R -- -- R Amphineura Ischnochiton comptus -- -- -- -- -- -- C C Pulmonata Onchidium verruculatum -- -- -- -- -- -- C C Cephalopoda Octopus honkongensis -- -- -- -- -- -- R -- Porifera Sponge -- -- -- -- -- -- R -- Annelida Tubular polychaetes -- -- -- -- -- -- A A

72


Fig 6.18 Population macrobenthic community on rocky substrate

Table 6.4 Population of macrobenthos in intertidal zone with rocky substratum

6.4.2.2 Biomass

Biomass of macrobenthic fauna of rocky surfacesrecorded the maximum value of 451.5 g/m2 fromupper intertidal zone of S-Control transect (Fig.6.19). However, S-ASSBY recorded the minimumbiomass. Biomass distribution in different transectsand their respective upper or lower intertidal zones,seems to be controlled by the proportionalcomposition of species. However, data vaguelyreveals that the lower intertidal zones recordedhigher biomass than the upper intertidal zone.Reason for this could be the direct human

disturbances like pollution in the upper intertidalzones.

Group N-Control N-ASSBY S-ASSBY S-Control UIT LIT UIT LIT UIT LIT UIT LIT

Crustaceans Barnacle 14167 11500 22917 6071 4167 21875 42218 Polychaetes - - - - - - 293 - Molluscans Oyster 64 - 13 18 9 7 9688 20500 Drupa - - 4 15 - - - - Chiton - - - - - - - 13 Octopus - - - - - - 1 - Calliostroma 51 - 9 18 20 6 473 66 Cerithids 110 - - - 28 - 616 452

6344

5

11526

32948

3294

8

6128

11526

143920

25000

50000

75000

100000


No.

/sq

m

Upper Inter tidal

Low er Intertidal

73


Fig 6.19 Biomass macrobenthic community on rocky substrate

6.4.2.3 Diversity

Jaccard's and Sorenson's similarity indices revealthat in terms of macrobenthic composition of rockysubstratum, the N-ASSBY and S-ASSBY had veryhigh level of similarity (0.56 and 0.71, respectively;Table 6.5). Similarly, the two control transectsrecorded very low level of similarity as indicatedby the two indices (0.18 and 0.31, respectively).

Table 6.5 Similarity index of macrobenthos in rocky substratum

Stations N-Control N-ASSBY S-ASSBY S-Control N-Control 0.53 0.55 0.31 N-ASSBY 0.36 0.71 0.48 S-ASSBY 0.38 0.56 0.40 S-Control 0.18 0.32 0.25

Sorenson index Jacard index

451.5

9.5

336.0

336.0

6.6 upp. inter.

9.5 upp. inter.

24.9

0

200

400

600

800


gm/s

q m

Upper Inter tidal

Low er Intertidal

74


6.5 MICROBIAL COMMUNITIES

This component focuses mainly on the microbialpopulation in the intertidal regions vis-à-vis theoil related pollution in the ASSBY area.Considering the complexity of the system, theresearch is focused on the estimation of totalnumber of micro-organisms and relative pre-dominance of different physiological types. Studyalso attempts to identify the oil degradationpotential of bacteria of the ASSBY area.

6.5.1 Methodology

The soil samples from two different sites at ASSBY(M-ASSBYand S-ASSBY) were collected in asterile bottle. For control, soil samples werecollected from the old Bhavnagar port atMathavad, approximately 50 km away from theASSBY. The bacteria were cultured in varioussuitable mediums with some known treatments.Standard techniques were used in culturing andcounting the bacteria (APHA, 1989).

6.5.2 Total Number of Bacteria

Since the soil samples were collected from theintertidal zone, it was essential to find out thebacterial population under different salinity levels.Three different concentration of NaCl werechecked for its effect on the growth of bacteria innutrient agar (NA) medium (Fig. 6.20). 3.4% NaClwas considered as sea water salinity. There was aqualitative variation in the number of bacteria thatcould tolerate different level of salinity. Especially,in S-ASSBY, the result indicate that the bacteriapresent were halotolerant. Almost equal numberof bacterial cells in all the three samples of 3%NaCl treatment indicate that the total microbialload was not affected by the ship breaking activity.Further analysis revealed that the bacteria countgo significantly high under the treatment ofunpolluted artificial sea water as compared withthe treatment of polluted water collected near theASSBY area (Fig. 6.21). This indicates that certainpollutants might suppress the growth of certainbacteria and deserves further research.

6.5.3 Physiological types

The relative abundance of bacteria capable ofdegrading agar, chitin and cellulose was estimated.The result highlights that the number ofchintinolytic and cellulolytic bacteria weresignificantly high in the soil samples from the twoASSBY sites, especially from the S-ASSBY (Table6.6). Since both these enzyme systems areinducible, the result indicates their highavailability in the area, possibly through differenttypes of pollutants.

75


4 45

6

8

18

7 8

17

0

2

4

6

8

10

12

14

16

18

20

Control M-Alang S-Alang

No.

of

cells

x (

107

cel

ls/m

l)

Nut. agar + sea water

Nut. agar + artific ial sea water

Zobell m arine agar

Fig 6.20 Viable count of bacteria on different media

Fig 6.21 Viable count of the Bacteria in Unpolluted sea water

Seaw ater %

119

28

6

3.4

15

4

13

4

0.5 0 .41 .5

0

10

20

30

E.c oli S. typh i S. dysentry

(x1

011

cel

ls/m

l)

n il

a t 50%

a t 80%

at 90%

76


6.5.4 Oil related microbes

One of the major pollutants at the ASSBY sites ispetroleum hydrocarbon, i.e., oils. The biologicaleffects of oil in the marine environment is wellstudied. In this study, the degradability of thehydrocarbon by microbial activity was analysedby gas chromatography (Hanson et al. 1994) andgravimetric methods. While during the shipbreaking activity various types of petroleumhydrocarbons are released and mixed with eachother, their degradability by microbial actions isvery difficult to ascertain. Keeping this in view, asrepresentative, 0.5% Bombay high crude (BHC)oil was used to test the microbial potential.

Table 6.6 Enumeration of bacteria of different physiological types from the soilsamples near Alang

Consortium of microorganisms from soil samplescollected at S-ASSBY and M-ASSBY showed the50% and 76% degradability of BHC, respectively,when analysed by gas chromatography (Fig. 6.22).However, a little less degradability was recordedby gravimetric analysis. These values weresignificantly high as compared to the controlsample. This result, therefore, suggested thatthough the total number of bacteria present at allthe sites were relatively constant (Fig. 6.20 and6.21), the number of oil degrading bacteria seemsto be very high in the polluted ASSBY area.

Sample. Viable Count of Organism (X 106 cells/g) Site Agarolytic Chitinolytic Cellulolytic

M-ASSBY 0.64 1.4 22 S-ASSBY 0.67 56.3 36 Control 2 3 7

3% (w/v) agar, 0.5% (w/v) chitin and 0.5% (w/v) cellulose was used as the sole carbon source in the basal medium. Composition of Basal Medium (g/100 ml) : Peptone, 1.0; NaCl, 0.1; K2HPO4, 0.1; KH2PO4, 0.1; MgSO4.7H2O, 0.05.

Fig 6. 22 BHC Oil degradation by consortium of microorganisms

31.7

48.74

76.1

65

31.6

18.3

0

20

40

60

80

Control M-ASSBY S-ASSBY

% d

egra

datio

n

Gas Chrometography Gravimetric

77


Further, it was of interest to isolate and characterisethe predominant bacteria from the soil samples ofASSBY area. On the basis of colony morphologyand biochemical assay, the most dominatingbacteria was tentatively identified to belong togenus Pseudomonas (Table 6.7).

6.6 CONCLUSION

The degradation in the water quality of theintertidal zone is related to enrichment of theorganic matter of all kinds: the biodegradable kind(as shown by increased BOD), non-biodegradablekind (as revealed by increased COD) and oil-PHC.However, significant spatio-temporal variations inparameters suggest sporadic loading and rapidsystemic assimilation. A number of pathogenicmicrobes have also been isolated which areprobably related to the continuous input ofdegradable organic matter into this system.

The sediments in the intertidal zone reveal

increased concentrations of nutrients, oil-PHC andsome heavy metals. While the nutrient enrichmentmay be due to the break down of organic matterpresent in water, oil-PHC and heavy metals occuras a result of direct input from shipbreakingactivities. It is interesting to note that hydrocarbondegrading microbes have been isolated mainlyfrom S-ASSBY where shipbreaking activity isrecent compared to M-ASSBY. It is likely thatincreased amount of heavy metals in M-ASSBYmay be acting as inhibitors for these specialisedmicrobes.

The macrobenthic population in ASSBY regionwas impoverished in terms of taxa richness,

Table 6.7 Identification of isolate 2 from the soil sediment of M-ASSBY

Size Shape Colour Margin Elevation Opacity Consistency 2 mm Round Green Uniform Slightly

raised Transluscent Mucoid

Biochemical test Results Pseudomonas Isolate 2

Gram’s Staining Reaction Cell Morphology Hanging drop motility Indole test Citrate utilisation Nitrate reduction Gelatin liquefaction Catalase test Oxidase Test Growth in Anaerobic Jar

Gram Negative Medium to small rods Motile Negative Positive Positive/Negative Positive Positive Strongly Positive Positive/Negative

Gram Negative Thin rods Motile Negative Positive Positive Positive Positive Strongly Positive Positive

Sugar fragmentation Glucose Lactose Sucrose Maltose Xylose Maltose

Negative Negative Negative Negative Negative Negative

Negative Negative Negative Negative Negative Negative

78


diversity and biomass. The molluscan populations,particularly in the upper and middle intertidalzones, were worst affected in this regard.Macrobenthic communities were similar in N-ASSBY and S-ASSBY but were different from thecontrol sites.

It may, therefore, be concluded that distinctchanges are taking place in the ecological set-upof the intertidal region due to disturbance causedby human activities. However, the damage ispresently contained by the assimilative capacityof the system and therefore calls for immediateand appropriate corrective actions. Regular studyand monitoring of the system is required on apriority basis to prevent further degradation andprovide for mid-course corrections.

79


7

OFFSHOREHYDROBIOLOGICALFEATURES

As mentioned earlier, the sub-tidal region off theshore of ASSBY is a highly dynamic system withvery high tidal amplitudes and strong currents.The biological productivity in this zone is lower,primarily due to high turbidity and lowerpenetration of sunlight. Fishing and othercommercial activity is less in this region whichperhaps explains the scant attention it has receivedfrom the scientific community so far.

Information on the ecological aspects of this regionis sporadic and fragmentary. Satyanarayana et al.(1971) provide a preliminary account of certainhydrobiological features of the Gulf of Khambhat.Later studies have mostly focused on specificparameters such as water quality (Zingde et al.1980, 1981 and 1985), sediment nature (Islam1984), zooplankton (Nair et al. 1981) and macro-invertebrates (Varshney et al. 1981, Rao andParulekar 1985).

However, it is well established that the Gulf ofKhambhat is a system with high energy regimeswhich manifests in very strong tidal currents,absence of any vertical stratification and largesuspended sediment load. The conditions createdare those characteristic of large, well mixedestuaries which export large quantities of detritusto the nearby open seas and converting these tofertile and productive regions. Although the extentof nutrient transport from the Gulf of Khambhatto the open ocean is yet to be studied, it is perhapsthe most important support system for sustainingthe high fish production in south Saurashtra coast.

Even by analysing the meagre scientific dataavailable, it becomes evident that the ecologicalfeatures of this region have witnessed significantchanges over the past few decades. The averagesalinity of the Gulf waters has increasedsignificantly and even a slight increase in theaverage water temperature has been reported.Some of the major factors that have probablycaused this shift are reduced discharge offreshwater from rivers draining into the gulf, input

of brine, shifts in equilibrium between evaporationand precipitation rates and global climate change.

Whatever may be the cause, such dramatic shiftsin salinity and hydrologic and energy regimesinduce large-scale changes to the Gulf and itsassociated ecosystems. A recent study on the spreadof salinity around the Gulf of Khambhat (GEC1997) reveals a drastic reduction of mangrovecover from over 350 sq km in 1960s to less than10 sq. km today. Satellite imageries revealincreasing silt deposition in the mouth of variousrivers draining into the Gulf and shift of mudbanksand shoals towards inland. Rapid industrialisationand changes in the quality of freshwater inputs inrecent years are some other causes needing athinking.

The present attempt at identifying the nature andextent of impact of ASSBY on the nearby offshorezone is, therefore, in the context of this highlydynamic and rapidly changing ecological scenario.

7.1 METHODOLOGY

7.1.1 Sampling strategy

Three rounds of comprehensive sampling duringOctober '96 (post-monsoon), December '96 (winter)and April '97 (pre-monsoon) were undertakenkeeping in view the overall objectives, availabletime frame and logistic factors. Sampling was donealong five transects:

I. N-Control: about 5 km north of ASSBYII. N-ASSBY: northern end of ASSBYIII. M-ASSBY: zone of maximum breakage

at the middle of ASSBYIV. S-ASSBY: southern end of ASSBYV. S-Control: about 5 km south of ASSBY

However, sampling was not done in the controlsites during the post-monsoon period. Each roundof sampling was completed in a single day coveringone flood and one ebb tide.

Three sampling points were located at distancesof 1 km, 3 km and 5 km at each of these transects.Samples were collected from both the surface andbottom layers. Since there was no significantvariation in most of the parameters with depth,

80


probably due to the shallow depth and mixingpattern, surface and bottom data was pooled inmost cases for each of the sampling stations.

7.1.2 Field and laboratory techniques

Water samples were collected using Niskinsampler, transferred to clean polyethylene bottlesand transported to a shore-based laboratory underappropriate conditions. A Van Veen type grabsampler (Plate 7.1) was used for collecting thebenthos while suitable nets were used for samplingthe plankton.

a) Current: The surface and near bottomcurrent at ten stations was measured byusing Roter currentmeter, covering onetidal cycle during the post monsooncondition.

b) pH and temperature : pH was measuredimmediately after the collection of samplewith a portable pH meter. The instrumentwas calibrated with standard buffer justbefore use.

c) Suspended Solids: 500 ml of water wasfiltered on preweighed millipore filter paper(Whatman GF type) having pore size of0.45 micron. These were oven-dried (at60°C), stored in a desiccator and re-weighed on digital balance. The values areexpressed as mg/l.

d) Salinity and Chloride Content: A suitablevolume of sample was titrated against silvernitrate (20 g/l) with potassium chromateas indicator. The salinity, expressed as partsper thousand (ppt), was calculated by usingKnudsen's Tables.

e) DO and BOD: Dissolved oxygen (DO) wasdetermined by the Winkler's method. Thevalues are expressed as mg/l. Directunseeded method was employed in thedetermination of Biochemical oxygendemand (BOD). The sample was filled in aBOD bottle in the field and was incubatedin laboratory for 5 days at 20º C after whichoxygen content was determined.

f) Nitrogen and phosphorus: Nitrite-nitrogen(NO2-N) in the sample was allowed to reactwith sulphanilamide in acid solution. Theresulting diazo compound was reacted withNC l-napthylene diamine to form a highlycoloured azodye which was measuredcolorimetrically using a Spectrophotometerat 543 nm. The results are expressed as mg/l.

g) Nitrate-nitrogen (NO3-N) was determinedby cadmium reduction method. The filteredseawater sample is passed through acolumn packed with amalgamatedcadmium to reduce the entire nitrate presentin the sample to nitrite, which is thenestimated by the azodye method. Theamount of nitrite originally present in thesample was subtracted from the totalamount of nitrite to obtain the concentrationin the sample. The values are expressed asmg/l.

h) Ammonia-nitrogen (NH3-N) wasdetermined using the Indo-phenol bluemethod. Ammonium compounds in watergive blue colour of endophenol whenreacted with phenol in presence ofhydrochlorite. The absorption of this colourwas measured at 630 nm using aSpectrophotometer and the resultsexpressed as mg/l.

i) Inorganic phosphate (PO4-P) wasdetermined by the ascorbic acid method.Acidified molybdate reagent was added tothe sample to yield a phosphomolybdatecomplex which was then reduced withascorbic acid to a highly coloured bluecompound. The absorption was measuredusing a Spectrophotometer at 882 nm andthe values expressed as mg/l.

j) Oil-PHC: Ten litres of seawater sample wascollected in a narrow mouth amber bottle(Plate 7.2) from a depth of 1m at each ofthe sampling stations. This was thenanalysed in the laboratory using standardmethods.

k) Phytoplankton pigments: For theestimation of phytoplankton pigments,

81


surface samples were collected. Chlorophylla, and phaeophytin were estimated byextraction of pigment in 90% acetonefollowing standard procedures.

l) Zooplankton: Oblique hauls were madeusing a Heron Trantor net (Plate 7.3; meshsize 0.3 mm and mouth area 0.25 m2). Allcollections were of 5 minute duration.Biomass was found out by displacementmethod.

m) Benthos: Sediment samples were collectedby using a Van veen type grab of 0.04 m2area. The sediment was sieved through 0.5mm mesh sieve and animals retained werestained with Rosebengal and preserved in5% buffered formaldehyde solution.

7.2 PHYSICO-CHEMICALFEATURES

7.2.1 Temperature, pH and salinity

During the study period, water temperature off thecoast of ASSBY varied from a minimum of 23.4ºCduring winter to a maximum of 31.9ºC duringpostmonsoon, both recorded close to the shore (1km). A slightly smaller range of variation intemperature was observed at 5 km off the shore ofASSBY (Table 7.1). The pH was alkaline, varyingbetween 7.9 and 8.2 (Table 7.2). Salinity was lowerduring the post-monsoon (27 - 28.8 ppt) and higherduring the pre-monsoon (33.3 - 33.7 ppt). Therewas no significant spatial variation in the levelsof salinity (Table 7.3).

82


Plate 7.1 Van Veen type grab sampler

Plate 7.2 Narrow mouth sampling bottle for oil

Plate 7.3 Heron Tantor net for zooplankton sampling

83


Table 7.1 Temperature. (ºC) variation of offshore water

- data not available

Table 7.2 pH variation in offshore water


Table 7.3 Salinity (ppt) variation in offshore water


Distance Season N-Control N-ASSBY M-ASSBY S-ASSBY S-Control 1 km Postmonsoon - 31.9 31.9 31.7 - Winter 24.2 25.4 24.7 24.7 23.4 Premonsoon 28.2 27.3 28.8 26.3 28.4 3 km Postmonsoon - 30.2 30.5 30.7 - Winter 24.3 24.7 24.7 26.5 23.9 Premonsoon 27.9 27.2 26.4 28.6 28.4 5 km Postmonsoon - 31 30.7 30.4 - Winter 24.5 25 24.9 24.9 24.1

Premonsoon 28.5 26.6 28.3 28.1 27.5

Distance Season N-Control N-ASSBY M-ASSBY S-ASSBY S-Control 1 km Postmonsoon - 7.9 7.95 7.95 - Winter 7.95 8 8 8 8

Premonsoon 8 8.1 8.15 8.05 8.1 3 km Postmonsoon - 8 8 7.95 - Winter 8 8 8.05 8.05 8.05

Premonsoon 8.05 8.05 8 8.05 8.05 5 km Postmonsoon - 8 8 8 - Winter 8 8 8.05 8 8.05

Premonsoon 8 8 7.95 8.05 8.15

Distance Season N-Control N-ASSBY M-ASSBY S-ASSBY S-Control 1 km Postmonsoon - 27.6 27 28.8 - Winter 30.6 30.4 30.3 30.7 30.6

Premonsoon 33.5 33.55 33.4 33.6 33.5 3 km Postmonsoon - 28.4 28.4 28.6 - Winter 30.5 31 30.4 30.4 30.8 Premonsoon 33.7 33.5 33.55 33.5 33.65 5 km Postmonsoon - 27.9 28.2 28.4 - Winter 30.3 30.5 30.6 30.7 31

Premonsoon 33.3 33.5 33.5 33.4 33.5

84


Variations in temperature and salinity are largelygoverned by seasonal changes and there is littlevariation between the different sites in the studyarea. Depth and distance from the shore also donot have any significant influence on thetemperature, pH and salinity of the water in thisregion.

7.2.2 Total suspended matter (TSM)

The TSM of the surface waters ranged from 14.6to 2995 mg/l, while that of the bottom watersranged from 43.2 to 4010 mg/l. TSM was relativelylower during the winter, possibly due to the lowerwind speeds during this period. Some prominentvariation in TSM can also be noticed between thesurface and bottom waters (Table 7.4). The spatialvariability was also without much significance.

Table 7.4 Suspended solids (mg/l) in offshore water

Distance Season N-Control N-ASSBY M-ASSBY S-ASSBY S-Control 1 km Post monsoon S 57.6 208.4 136.8 - -

B 1971.2 3824.4 4010.4 - - Winter S 721.0 629.0 98.4 14.6 71.4 B 156.4 85.8 103.2 747.8 43.2 Premonsoon S 864.0 118.0 1111.0 667.0 1671.0 B 732.0 2425.0 3736.0 1153.0 1473.0

3 km Post monsoon S 103.6 166.0 187.6 - - B 748.4 3365.2 3566.4 - - Winter S 305.6 115.0 102.4 478.2 56.2 B 352.0 186.2 39.8 379.6 1187.2 Premonsoon S 363.0 372.0 528.0 1814.0 2476.0 B 4466.0 3486.0 1253.0 1945.0 2720.0

5 km Post monsoon S 420.0 148.0 964.8 - - B 2838.0 3028.0 1495.6 - - Winter S 65.8 2995.0 686.0 82.3 156.8 B 305.6 698.6 168.6 752.4 208.9 Premonsoon S 367.0 1408.0 687.0 1099.0 427.0 B 735.0 3618.0 655.0 3393.0 966.0

- data not available: S - Surface; B - Bottom

85


7.2.3 DO and BOD

The dissolved oxygen (DO) in offshore waters wasslightly lower (5.3 - 7.3 mg/l) during premonsoonthan during post-monsoon (6.2 - 7.1 mg/l) orwinter (6.2 - 7.9 mg/l) during winter. There wasno significant variation between the different studysites (Table 7.5). DO was also not affected in anysignificant manner by the distance from shore.

Table 7.5 DO in offshore water


The spatial and temporal variation of biochemicaloxygen demand (BOD) are presented in Fig. 7.1.Highest BOD (6.6 mg/l)was recorded at 1 km offthe shore of Northern ASSBY followed by 6 mg/lat 3 km off the shore of Middle ASSBY, bothduring the post-monsoon period. This suggests anincreased organic loading in the off-shore areaduring post-monsoon period, probably as drainagefrom the onshore region. BOD is lowered duringwinter, possibly due to the increased availabilityof dissolved oxygen. However, during thepremonsoon, BOD at ASSBY area was alwayshigher compared to the control sites and there was

hardly any difference with distance from the shore.

7.2.4 Nitrogen and phosphorus

The NO3-N content was highest during the post-monsoon (491 - 572 µg/l), decreasing during thewinter (389 - 420 µg/l) and lowest during the pre-monsoon (210 - 323 µg/l). There was no significantspatial variation (Fig.7.2).

DO (mg/l) N-Control N-Alang M-Alang S-Alang S-Control 1 km Postmonsoon - 7.1 7 6.25 - Winter 6.95 7.85 6.2 7.55 7.9

Premonsoon 6.7 6.55 5.3 6.55 6.8 3 km Postmonsoon - 6.7 6.7 6.2 - Winter 7.1 7.7 6.35 6.35 7.65

Premonsoon 5.3 7.2 6.4 6.7 7.15 5 km Postmonsoon - 6.65 6.5 6.5 - Winter 6.2 6.65 7.4 7.85 6.95

Premonsoon 5.75 7.3 6.6 6.75 6.65

86


Fig 7.1 Variation of biochemical oxygen demand (BOD) in offshore water

1 km 6.6

3.4

2.3

3.4

0.5

2.22.7 2.4

1.7

3.1 2.82.2 2.2

0

2

4

6

8

N-C ontro l N-ASSBY M-ASSBY S-ASSBY S-C ontrol

mg

/l

Postm ons oon

W inter

Premonsoon

3 km

2.3

6

0.9

3.4

0.6 0.6 0.6

3.6

0.8

2.82.4 2.4

0.8

0

2

4

6

8


mg

/l

5 km

3.32.9

2.5

0.6

2.4 2.4 2.43.2

1.4

3.12.6

3.4

1.4

0

2

4

6

8

N-C ontrol N-ASSBY M-ASSBY S-ASSBY S-C ontrol

mg/

l

87


Fig 7.2 Variation of NO3-N content in offshore water

1 km 572

403 403 420 405

249 231 221

323

212

511 546

394

0

100

200

300

400

500

600

700


(µg

/l)

Postm onsoon

W inter

Premonsoon

3 km 499 491 495

413 403 390410 399

281226 211 228 241

0

100

200

300

400

500

600

N-C ontrol N-ASSBY M-ASSBY S-ASSBY S-Contro l

(µg/

l)

5 km 509 515 493

409 392 401 403 396

251 245 232 235 235

0

100

200

300

400

500

600

N-C ontrol N-ASSBY M-ASSBY S-ASSBY S-Contro l

(µg/

l)

88


The NO2-N content, on the other hand was lowerduring the post-monsoon (4 - 11 µg/l), varyingduring the winter (4 - 24.5 µg/l) and higher duringthe pre-monsoon (8 - 20 µg/l). There was nosignificant spatial variation (Fig. 7.3).

There was a wide fluctuation in the NH4-N contentin the study area (Fig. 7.4). However, it is difficultto derive any meaningful pattern from this spatio-temporal variation.The PO4-P concentration was relatively higher (90- 157 µg/l) during the post-monsoon compared tothe winter (73-114 µg/l) and pre-monsoon (50-146 µg/l). This seasonal variation was morepronounced closer to the shore (1 and 3 km)compared to farther off (5 km). There was nosignificant difference in PO4-P concentration inthe ASSBY area compared to the control sites (Fig.7.5).

7.2.5 Oil and PHC

PHC concentration was generally below 35 µg/lin the study area (Fig. 7.6). However, much higherconcentrations (85 - 182 µg/l) have been recordedat 5 km offshore of the study area, particularlyduring the post-monsoon and winter samplingperiods.

7.3 BIOLOGICAL FEATURES

7.3.1 Phytoplankton pigments

The concentration of chlorophyll a is a measureof biomass productivity in the offshore aquaticsystem. Higher concentration of chlorophyll a (Fig.7.7) was recorded during the post-monsoon period(1.07 - 2.67 µg/l) compared to the winter (0.5 -0.8 µg/l) and pre-monsoon (0.5 - 1.7 µg/l). Evenduring the post-monsoon, the 5 km offshore zonerecorded a slightly higher chlorophyll a contentcompared to the 1 km and 3 km offshore zones.There was no significant variation between thecontrol sites and the sites within ASSBY.

89


Fig 7.3 Variation of NO2-N content in offshore water

1 km

67.5

10.99

11.5

9

5 .5

8 .510.5

14

17.5

8

20

0

5

10

15

20

25


(µg/

l)

Pos tmons oon

W in ter

Prem onsoon

3 km

4 4.96 .6

13

10.5 10.5

64

9

11.5

16.5

11

22

0

5

10

15

20

25


(µg

/l)

5 km

5.2 5 .8

8.910.5

12

8 .5

4.5

7 .5 8

11.513 .5

18.5

24.5

0

5

10

15

20

25

30

N-C ontro l N-ASSBY M-ASSBY S-ASSBY S-Contro l

(µg/

l)

90


Fig 7.4 Variation of NH4-N content in offshore water

1 km

5.31.8

3.97

35

79

5.5

25

118.5

0

10

20

30

40

50

N -Contro l N-ASSBY M-ASSBY S-ASSBY S-C ontro l

(µg

/l)

Pos tmons oon

W inter

Prem ons oon

3 km

5.3 4.60.7

15

42.5

59

22

8

15

4.5

0

10

20

30

40

50

N -Contro l N-ASSBY M-ASSBY S-ASSBY S-Contro l

(µg

/l)

5 km

20.5 21.5 20.6

13

18

35

13

139

3

0

10

20

30

40

50


(µg/

l)

91


Fig 7.5 Variation of PO4-P content in offshore water

1 km

89.5 90

157

107.5 113 .5103

76.5 73

98

78.5 72.5

50

98

0

40

80

120

160

200

N-C ontro l N-ASSBY M-ASSBY S-ASSBY S-C ont rol

(µg

/l)

Pos tmons oon

W inter

Prem onsoon

3 km

132

89 8499

9079

146

78.5 76 80 73

169 173

0

40

80

120

160

200

N-C on trol N-ASSBY M-ASSBY S-ASSBY S-C ont rol

(µg

/l)

5 km

93.5 91.595.584 8582

95.5 88.59994.5 94

102.5

75.5

0

40

80

120

160

200

N-C ontro l N-ASSBY M-ASSBY S-ASSBY S-Contro l

(µg

/l)

92


Fig 7.6 Variation of Oil-PHC content in offshore water.

45.5

24 .4 258.7 12 .1 12.7

30.1 23.4 31 .32019.2

28.731.3

0

25

50

75

100

125

150

175

200

N-Contro l N-ASSBY M-ASSBY S-ASSBY S-C ontrol

1 km

(µg

/l)

Postm onsoon

W inter

Premons oon

45.729 .6

14 .1 10.7 14.9 22.431 .3 29 .7 19.6

20.8

27

26.221 .6

0

25

50

75

100

125

150

175

200


3 km

(µg

/l)

5 km

85.8

164.2

14.5 11.5

113 .2

24.634.9

181 .5

124.7

18 20 21.6 27 .4

0

25

50

75

100

125

150

175

200


(µg

/l)

93


Fig 7.7 Variation of Chlorophyl a content in offshore water.

1 km

1.61

1.07 1.07

0.8 0 .80 .53 0.53 0 .530.53

0.8

1.07

0.53 0.53

0

1

2

3


(µg

/l)

Pos tm ons oon

W in ter

Prem onsoon

3 km

1.07 1 .07

2.14

0 .8

0 .53 0.530.53 0 .53

0.8

0 .53

1.7

0.53 0.53

0

1

2

3


(µg/

l)

5 km

1.61

2.14

0.80 .53 0.53

1 .10.8 0.8

0.530.8

2.67

0 .80 .53

0

1

2

3

N-C ont rol N-ASSBY M-ASSBY S-ASSBY S-C ontro l

(µg

/l)

94


Phaeophytin concentration is usually low (< 2 µg/l) in the offshore waters of the study area (Fig.7.8). However, there is a distinct increase in thephaeophytin level (2.5 - 5.25 µg/l) during thewinter season. Again, no significant spatialvariation could be observed.

7.3.2 Phytoplankton

Table 7.6 Variation in Phytoplankton at different stations at Alang


There was adistinct seasonal variation in thephytoplankton density observed in the offshorewaters of the study area (Table 7.6). It was highestduring the post-monsoon (11,500 - 164,800 nos.l-1) and much lower during the winter and pre-monsoon periods (3,200 - 19,600 nos.l-1). Therewas also a distinct shift in the dominance of majorgroups of phytoplankton over the different seasons.Navicula sp., Nitzschia sp. and Thalassiosira sp.dominated during the post-monsoon whileCoscinodiscus sp. begins to dominate duringwinter. Other diatoms like Cyclotella sp. andPleurosigma sp. appear during the pre-monsoonto dominate the phytoplankton assemblage alongwith Coscinodiscus sp.

Stations Population range (no/l) Post-monsoon Winter Pre-monsoon

N-Control 22560-164800 5600-19600 5600-19600 N-ASSBY 24960-86400 4000-14000 4800-10000 M-ASSBY 11500-110400 4000-6000 3200-16000 S-ASSBY - 4800-10000 4000-6000 S-Control - 3200-12800 6000-14000 Major genera Navicula sp. Coscinodiscus sp. Coscinodiscus sp. Nitschia sp.. Navicula sp. Nitschia sp. Thalassioira sp. Nitzschia sp. Cyclotella sp. Rhizosolenia sp. Thalassisors sp. Pleurosigma sp.

95


Fig 7.8 Variation of Phaeophytin content in offshore water

1 km

0.430 .96

0.590.96

0.2

1.7

3 .663 .12

3 .5

4.89 4.7

1.07

0.43

0

1

2

3

4

5

6


(µg

/l)

Pos tm onsoon

W in ter

Prem ons oon

0 .43

1.92

0.430.96

1.7

0 .2

4 .143.87 3 .96

2.51

5.26

0

1

2

3

4

5

6

N-C on trol N-ASSBY M-ASSBY S-ASSBY S-C on trol

3 km

(µg

/l)

5 km

1 .070.59

1.7

0.78

2.86 2.94 2.94

4 .11 4 .33

0

1

2

3

4

5

6

N-C on trol N-ASSBY M-ASSBY S-ASSBY S-C ontro l

(µg

/l)

96


7.3.3 Zooplankton

Again, a distinct seasonal shift in the compositionand density of zooplankton was observed in theoffshore waters of the study area (Table 7.7). Onlysix groups were recorded during the post-monsoonwhich included copepods, their nauplii andcirripeds. Chaetognaths, copepods and larvae ofdecapods and gastropods dominated thezooplankton assemblage during the winters whena maximum of 13 groups were recorded. Therecorded number of groups reduced to 7 duringthe pre-monsoons, among which salps, fish larvae,copepods, crustacean larvae and chaetognaths were

Major genera Copepods, cirripds, naupliiChaetognaths, copepods decapods, larvae,gastropods salps, fish larvae, copepods, crustacean larvae, chaetognaths - data not available

Post monsoon Winter Premonsoon Stations Max

No Population

range (no/1000

m3)

Max

No

Population range

(no/1000 m3)

Biomass (ml/100

m3)

Max

No

Population range (no/1000

m3)

Biomass

(ml/100 m3)

N-Control - - 13 1226-1566 0.31 6 240-642 2.00 N-ASSBY 6 - 13 1297-1327 0.66 5 217-5687 1.35 M-ASSBY 3 - 13 990-1500 0.59 6 2024-19698 3.55 S-ASSBY 5 - 12 603-1576 0.9 5 208-5223 1.32 S-Control - - 13 2154-4620 1.74 7 625-

14036 1.52

Major genera

Copepods, cirripds, nauplii

Chaetognaths, copepods decapods, larvae, gastropods

salps, fish larvae, copepods, crustacean larvae, chaetognaths

Table 7.7 Variation in Zooplankton at different stations at Alang

97


prominent.

The population of zooplankton was high duringboth the winter (603 - 4,620 nos/ml) and pre-monsoon (208 - 19,700 nos/ml) seasons. There wasalso a definite increase in the zooplankton biomassfrom winter (0.31 - 1.74 ml/100m) to pre-monsoon(1.32 - 3.55 ml/100m), possibly due to thedominance of salps and fish larvae.

7.3.4 Benthos

The macro-benthic community is composed of onlya few forms, such as polychaetes, molluscs, prawnlarvae and ostracods. The total population densityis also seldom more than 50 nos.m2. Somewhathigher numbers were recorded during the pre-monsoon period. The biomass was also negligible.Foraminiferans dominated the meiobenthiccommunity. A total of 48 species of recent benthicforminifera belonging to 25 genera under 13 familywere identified and reported from the study side.The N-Control transect was the most healthytransect. Among the three transects around theAlang ship-breaking yard, the N-ASSBY transect

was the most stressed transect having almost aforaminiferal dead zone within which only twoopportunistic species Ammonia beccarii &Nonionenllina turgida survive. No agglutinatedforaminifera were encountered from the study area.Many of the forams might well have shifted theecological niche to avoid the ecological crisis. Thesize reduction of certain forams like Ammonia spp.clearly indicates ecological degredation. Thecontaminants from the ship breaking yards inflictdamages to the resident foraminiferal faunadirectly or indirectly by destroying the feedingmaterial of the forams.

7.3.5Fishery

The fish landing data was obtained from theDepartment of Fisheries, Government of Gujarat.No landing is reported from the ASSBY area. Thenearest landing centres are Ghogha and Bhavnagarin the North (60 km away) and Katpar in the South(again 50-60 km away). All commerciallyimportant fish (such as Bombay duck, Hilsa,Mullets, Prawns etc.) landings reveal a decreasingtrend from 1991 to 1995 (Table 7.8), although incase of shrimp the increase at Katpar may be

Table 7.8 Fish landing data (kg/yr) at the neighbourhood of ASSBY.


Name of fish GHOGHA KATPAR BHAVNAGAR LOCKGATE

1991 1995 1991 1995 1991 1995 Bombay duck 102,069 93,862 116,865 46,129 74,792 32,591

Hilsa 7,020 Nil 31,762 15,860 Nil Nil Clupid 1,860 Nil 22,905 23,309 - - Mullet 44,308 24,809 112,695 12,776 - 5,689 Catfish 2,175 - 13,950 2,250 - - Colmi

(Shrimp) 175,250 909,151 30,015 48,072 20,240 62,004

Medium prawn 704,179 408,121 108,534 18,690 78,180 27,831 Jumbo prawn 214,314 80,400 30,225 Nil - -

Lobster 87,141 21,199 1,500 2,769 3,162 110,639 Coilie - - 3,348 - - - Dhoma

(Scianoid) - - 11,487 3,565 - -

Other fish 420,538 186,427 106,951 27,854 34,056 52863,089

98


attributed to increased effort.

7.4 IMPACT OF ASSBY ON THEOFFSHORE ECOSYSTEM

Many of the hydrobiological features describedabove suggest the predominance of seasonal factorsover others. The post-monsoon period ischaracterised by large input of freshwater, throughsurface drainage, resulting in a drop in salinity,increased turbidity and enrichment of nutrients.This leads to an increase in the primaryproductivity, as evident from the increase inchlorophyll a, and the density of phytoplankton.Grazing causes a sharp decrease in phytoplanktondensity during winter with a correspondingincrease in both the number of species and densityof zooplankton. The species composition ofphytoplankton also changes, with a correspondingchange in the concentration of phytoplanktonpigments.

Species composition of both phytoplankton andzooplankton changes during pre-monsoon. Manyof these are the hardy types, capable of survivinghigher salinity ranges and reduced concentrationsof oxygen and nutrients.

The study reveals that loading of organic matterfrom surface drainage in the ASSBY region mightbe contributing to the BOD of these waters.However, higher levels of BOD have also beenobserved elsewhere in the gulf region by Zingde(1980a & 1980b, 1981 and 1985). NH4-N, adecomposition product from organic matter is alsoobserved occasionally in higher concentrations.NO2-N concentration is also consistently higherduring the pre-monsoon. These forms of nitrogenhave the potential to reduce productivity and caneven prove toxic to the biotic systems, although atmuch higher concentrations.

Another important impact is the occurrence ofpetroleum hydrocarbons in this region. Althoughoil-PHC levels are lower in 1 and 3 km offshorezones, considerably higher values were recordedat 5 km offshore zone during the post-monsoonand winter sampling periods. Oil pollution in theintertidal area along the South Gujarat coastlinehave been reported much earlier (Dwivedi et al.1974). Increase in the petroleum hydrocarbonconcentrations in the sediments of western Arabian

Gulf has also been reported (Stephen et al. 1990).

7.5 CONCLUSION

The predominance of the seasonal and othernatural factors in the functioning of the offshoreecosystem suggest very little anthropogenicdisturbance, particularly those related to immediateand concentrated activities such as ship-breaking.The problems, as mentioned in the initial sectionsof this chapter, are obviously related to more broad-based changes operating on a wider scale.

The slight increase in BOD and certain nutrientsin the near shore waters (1 to 3 km) indicateloading of organic matter form the ASSBY region.The levels are also seen to reduce drastically atthe 5 km zone. Therefore, it might be concludedthat any effort made to reduce the input of organicmatter in the intertidal region would naturally takecare of the problem in the offshore zone as well.Oil-PHC has much lower natural degradability andhence efforts will be required to reduce its escapeinto the marine system. The levels of heavy metalsare also within acceptable limits at present butconstant monitoring would be required to ensurethat levels do not build-up beyond the criticallevels.

99

gec alang report (main document part i)

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