Definition of estuaryDefinition of estuary☼ An estuary is defined as a semi-

enclosed coastal body of water, which has a free connection with the open sea and within which the seawater is measurably diluted with the freshwater of land drainage.

• Estuaries are important & distinct Estuaries are important & distinct component of coastal landscape with component of coastal landscape with highly complex ecosystems,varying highly complex ecosystems,varying physicochemical properties & highly physicochemical properties & highly diverse flora & fauna.diverse flora & fauna.

• Estuaries are of different shapes & sizes, & Estuaries are of different shapes & sizes, & are known by different names,such as are known by different names,such as ‘river mouth’,’bays’,’lagoons’,’harbours’ or ‘river mouth’,’bays’,’lagoons’,’harbours’ or ‘inlets’.‘inlets’.

ESTUARINE RESOURCES OF INDIA

• Indian coastline is Indian coastline is more than 7500km more than 7500km in length with an in length with an EEZ of 2.015 X 10EEZ of 2.015 X 1066 kmkm22 that accounts that accounts for 61% of total land for 61% of total land area.area.

• The country commands a distinct position The country commands a distinct position with more than 55 estuaries,located on with more than 55 estuaries,located on East & west coastsEast & west coasts

• The estuarine resource,including the The estuarine resource,including the associated waters,of India has been associated waters,of India has been estimated approx. at 30,000,00 ha.estimated approx. at 30,000,00 ha.

• Amoung the major rivers Ganga, Mahanadi, Amoung the major rivers Ganga, Mahanadi, Godavari,Krishna,Cauveri [east coast] & Godavari,Krishna,Cauveri [east coast] & Narmada,Tapti,Mandovi,Zuari [west coast] Narmada,Tapti,Mandovi,Zuari [west coast] forms highly productive esuarine systems forms highly productive esuarine systems esp. in relation to fisheries.esp. in relation to fisheries.

PRESENT STATUS OF FISH PRODUCTION & PRODUCTIVITY

• The estuarine fisheries in India are The estuarine fisheries in India are always above the subsistence always above the subsistence level,contributing sizably to the level,contributing sizably to the inland fish basket in the country.inland fish basket in the country.

• The fish productivity of various The fish productivity of various estuaries has been estimated in the estuaries has been estimated in the range of 45-75 kg/ha.range of 45-75 kg/ha.

ECOLOGY AND FISHERIES OF SELECTED ECOLOGY AND FISHERIES OF SELECTED ESTUARIES ESTUARIES &&

ASSOCIATED WATERSASSOCIATED WATERS

• HOOGHLY ESTUARYHOOGHLY ESTUARY• Largest estuarine systems in India.Largest estuarine systems in India.• width 2-12km.width 2-12km.• Salinity : 0.2-31.6 pptSalinity : 0.2-31.6 ppt• live estuary supporting rich live estuary supporting rich

biodiversity biodiversity • better known for its profitable winter better known for its profitable winter

fishery,the famous sunderban fishery,the famous sunderban mangroves & Hilsa fishery.mangroves & Hilsa fishery.

TRENDS OF FISH CATCHTRENDS OF FISH CATCH• The trend of fish catch in Hooghly indicated The trend of fish catch in Hooghly indicated

significant increase during recent years significant increase during recent years primarily due to increase in Hilsa catch.primarily due to increase in Hilsa catch.

• Between 1998-99 & 2002-2003,the Between 1998-99 & 2002-2003,the average per annum catch of Hilsa has been average per annum catch of Hilsa has been estimated at 10,382.9t with an impressive estimated at 10,382.9t with an impressive increase of 63.3% from previous 5 years increase of 63.3% from previous 5 years [6279.6t][6279.6t]

KRlSHNA ESTUARY• Salinity : 20-35ppt.Salinity : 20-35ppt.• fishery dependent on marine fishery dependent on marine

migrants.migrants.• Mullets are hallmark of Krishna Mullets are hallmark of Krishna

estuary.estuary.• Other gps. found in catch include Other gps. found in catch include

clupeids,perches,catfish,penaid clupeids,perches,catfish,penaid prawns & crabs. prawns & crabs.

• Annual fish catch during 2004-06 has Annual fish catch during 2004-06 has been estimated at 496.1 – 540t with been estimated at 496.1 – 540t with productivity ranging from productivity ranging from 83-90kg/ha.83-90kg/ha.

• Average catch per unit of effort - low Average catch per unit of effort - low & depend on season – 13.6kg/boat & depend on season – 13.6kg/boat [post-monsoon] & 1.74kg/boat[pre-[post-monsoon] & 1.74kg/boat[pre-monsoon].monsoon].

GODAVARI ESTUARY• Andra Pradesh.Andra Pradesh.• Two disributariesTwo disributaries – –east flowing Gautami-Godavari estuary east flowing Gautami-Godavari estuary

& & south flowing Vashista –Godavari estuary.south flowing Vashista –Godavari estuary.• Extensive mangrove swamps flank Extensive mangrove swamps flank

Gautami – Godavari estuary & supports Gautami – Godavari estuary & supports prawn fishery. prawn fishery.

• Godavari estuary as a whole supports Godavari estuary as a whole supports 23 prawn sps. Of this 23 prawn sps. Of this Penaeus Penaeus indicus,P.monodon, P.japonicus indicus,P.monodon, P.japonicus etc etc are impo. from fishery point of view.are impo. from fishery point of view.

• Palaemonid prawns like Palaemonid prawns like Macrobrachium Macrobrachium rosenbergii,M.malcomsonii etc are rosenbergii,M.malcomsonii etc are also impo..also impo..

MAHANADl• Comprises 2 impo. estuaries of Odisha viz. Comprises 2 impo. estuaries of Odisha viz.

Mahanadi & Devi.Mahanadi & Devi.• Salinity : 0.6-18 ppt.Salinity : 0.6-18 ppt.• Fishery include – mullets,prawn,thread Fishery include – mullets,prawn,thread

fins,perches & others contributed by 96 fins,perches & others contributed by 96 sps. of fin fish & 10 sps. of shell fish.sps. of fin fish & 10 sps. of shell fish.

• Sps. diversity differs with depth & salinity.Sps. diversity differs with depth & salinity.• However,relatively higher fish However,relatively higher fish

catch ,coupled with higher diversity, has catch ,coupled with higher diversity, has been recorded towards seamouth as been recorded towards seamouth as compared to freshwater stretch compared to freshwater stretch

CHILKACHILKA• Largest lagoon in the east coast of India.Largest lagoon in the east coast of India.• Lagoon has distinct marine,brackish & Lagoon has distinct marine,brackish &

fresh water strands but is primarily an fresh water strands but is primarily an estuarine ecosystem.estuarine ecosystem.

• Ramsar site.Ramsar site.• Endangered sps. & migratory birds.Endangered sps. & migratory birds.• Highly productive with rich fishery Highly productive with rich fishery

resources.resources.• Potential source for high priced prawn & Potential source for high priced prawn &

mullet fisheries.mullet fisheries.

PULICAT LAKEPULICAT LAKE• Second largest brackish water lake in Second largest brackish water lake in

India.India.• Run //l to Bay of Bengal.Run //l to Bay of Bengal.• Opens into Bay of Bengal through a Opens into Bay of Bengal through a

narrow passage at its southern narrow passage at its southern end,near Pulicat town.end,near Pulicat town.

• Shallow lake – average water Shallow lake – average water depth :0.7m.depth :0.7m.

• Salinity : 7.79 – 28.91 ppt. Salinity : 7.79 – 28.91 ppt.

• Fishery – largely depend on Fishery – largely depend on P.indicus,M.cephalus & Chanos P.indicus,M.cephalus & Chanos chanos.chanos.

• However dominant fishery of Chanos However dominant fishery of Chanos chanos in 1980s become rare.chanos in 1980s become rare.

• Fisheries of Sardinella,Hilsa,tiger Fisheries of Sardinella,Hilsa,tiger prawn also declined significantly prawn also declined significantly [over fishing].[over fishing].

• Penaeid prawns of importance – Penaeid prawns of importance – Metapeneaeus dobsonii,M.monoceros Metapeneaeus dobsonii,M.monoceros & M.brevicornis.& M.brevicornis.

• The crab fishery – very conspicuous.The crab fishery – very conspicuous.

• The use of destructive gears,esp. The use of destructive gears,esp. small mesh bar nets,has lead to small mesh bar nets,has lead to indiscriminate fishing of mullets.indiscriminate fishing of mullets.

• The average catch per fisher per day The average catch per fisher per day has been estimated to be poor at has been estimated to be poor at 300g-500g/day,mainly of P.indicus300g-500g/day,mainly of P.indicus

KERALA BACKWATERSKERALA BACKWATERS• 44 rivers in Kerala,41 flows 44 rivers in Kerala,41 flows

westwards from W.G to Arabian sea westwards from W.G to Arabian sea through backwater.through backwater.

• Total area : 500 sq.kmTotal area : 500 sq.km• Comprises of vast system – Comprises of vast system –

interconnected lagoons,bays & interconnected lagoons,bays & swamps.swamps.

• Fish landing :14000-17000tFish landing :14000-17000t

• Vembanad is largest backwater.Vembanad is largest backwater.• Northern part of vembanad – cochin Northern part of vembanad – cochin

backwater.backwater.• River Periyar in north & Pampa in River Periyar in north & Pampa in

south along with many small south along with many small channels,streams,irrigation canals channels,streams,irrigation canals etc –freshwater source of cochin etc –freshwater source of cochin backwater.backwater.

• Salinity : 9-11pptSalinity : 9-11ppt

ANNUAL LANDING (%)ANNUAL LANDING (%)• Prawn : 60-70%• P.indicus, Metapeneaeus dobsonii, P.indicus, Metapeneaeus dobsonii,

M.monoceros , Macrobrachium rosenbergii.M.monoceros , Macrobrachium rosenbergii.• Mullets : 11%Mullets : 11%• Mugil cephalus,M.macrolepis,M.parsia• Pearl spot : 10%• Etroplus suratensis,Etroplus maculatus• Catfish :9%• Others :1%

ReferencesReferences• ESTUARINE FISHERIES

MANAGEMENT- OPTIONS & STRATEGIES[Central

Inland Fisheries Research Institute(Indian Council of Agricultural

Research)]• www.fao.org• www.fishbase.org• agritech.tnau.ac.in