8. fish resource assessmentshodhganga.inflibnet.ac.in/bitstream/10603/28278/14... · it could refer...

8. FISH RESOURCE ASSESSMENT

8.1 Introduction

Fishes form one of the most important groups of vertebrates, influencing its life

in various ways. Millions of human beings suffer from hunger and malnutrition and

fishes form a rich source of food and provide a meal to tide over the nutritional

difficulties of man. In addition to serving as an important item of food, fishes provide

several by-products to us. Fishes have formed an important item of human diet from

time immemorial and are primarily caught for this purpose. Fish diet provides proteins,

fat and vitamins A and D. A large amount of phosphorous and other elements are also

present in it. They have a good taste and are easily digestible (Sarwade and Khillare,

2010).

Fish constitutes half of the total number of vertebrates in the world. They live in

almost all conceivable aquatic habitats; 21,723 living species of fish have been recorded

out of 39,900 species of vertebrates out of these 8,411 are freshwater species and 11,650

are marine. India is one of the mega biodiversity countries in the world and occupies the

ninth position in terms of freshwater mega biodiversity (Mittermeier and Mitemeir,

1997). Ichthyodiversity refers to variety of fish species; depending on context and scale,

it could refer to alleles or genotypes within fish population to species of life forms

within a fish community and to species or life forms across aqua regimes (Burton, et al.,

1992).

The eastern Himalayan region encompassing the Northeast is considered as one

of the hot spots of freshwater fish biodiversity in the world (Kottelat and Whitten,

1996). The north eastern region of India has unique topographical conditions. The eco

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climatic zone of freshwater fishery ranges from warm water drainage system to minus

zero degree temperature conditions. As a result, the region is blessed with vast and

varied water resources in the form of rivers, reservoirs, beels, lakes, swamps etc.

Riverine fishery plays in an important role in the region, which harbours the natural

stocks of the fish species. The region is blessed with 56 notable rivers/tributaries and

several small rivulets/hill streams. Two major river systems of the region are the

Brahmaputra and the Barak along with their tributaries constitute important fishery

resources of the region particularly in Assam.

The freshwater ichthyodiversity of Assam was reported by various workers.

Some of the pioneering works on ichthyofauna of river Brahmaputra were conducted by

Hamilton (1814), MeClelland (1839), Beavan (1877), Hunter (1879) and Day (1877 and

1889). Later, during the 20th century, several workers studied the taxonomy and

distribution of fishes in the Brahmaputra river system. Among them De (1910) studied

the fishery potentialities of Eastern Bengal and Assam. Hora (1922 and 1936) reported

the fish species of the hilly areas of Assam. Sehgal and Motwani et al. (1962) studied

the fisheries of river Brahmaputra. There are a few reports available on the

hydrobiology and fisheries of the Brahmaputra basin (Dey, 1976 and 1984; Jhingran,

1991; Yadav and Sugunan, 1992; Biswas et al., 1995; Biswas, 1998 and Biswas and

Boruah, 2000).

Moreover the freshwater ichthyodiversity of Assam was also reported by Dey

(1973 b), Dey (1981), Dey (1982), Nath (1987), Boruah (1999), Biswas and Boruah

(2002), Das and Biswas (2006), Das (2007) and Das and Biswas (2008). Although

survey on ichthyofauna of this region has been carried out by a few workers, but yet in

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Assam, there is no detailed information regarding the diversity, abundance and status of

tributaries of the Brahmaputra river system.

8.2 Results:

During this investigation 70 fish species belonging to 53 genera, 18 families and

7 orders have been recorded from the five stations of Pagladia (Fig-42). The ichthyo

species of the tributary belong to following orders- Osteoglossiformes, Cypriniformes,

Siluriformes, Perciformes, Beloniformes, Synbranchiformes and Cyprinodontiformes.

Out of these 70 species, 2 belong to family Notopteridae, followed by Cyprinidae (30),

Nemacheilidae (3), Cobitidae (3), Bagridae (6), Siluridae (2), Schilbeidae (4),

Pangasiidae (1) Sisoridae (2), Olyridae (1), Ambassidae (2), Anabantidae (1),

Belontiidae (3),Channidae (4),Gobiidae (1),Belonidae (1), Mastacembelidae (3),

Aplochelidae (1).The collected fish species from the five different stations are depicted

in table-43.

3%

52%23%

16%1% 4% 1% Osteoglossiformes

CypriniformesSiluriformesPerciformesBeloniformesSynbranchiformesCyprinodontiformes

Fig-42: Percentage contribution of different orders of Fish in Pagladia river

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Order Family Name of the speciesS-

1

S-

2

S-

3

S-

4

S-

5

Osteoglossiformes Notopteridae

Chitala chitala (Hamilton) - - + + +Notopterus notopterus

(Pallas)- - + + +

Cypriniformes Cyprinidae Amblypharygodon mola

(Hamilton)- - + + +

Aspidoparia jaya (Hamilton) - - + + +A. morar (Hamilton-

Buchanan) - - + + +

Bangana dero (Hamilton) + + - - -Barilius barila (Hamilton) - - + + +B. bendelisis (Hamilton) - - + + +B. vagra (Hamilton-

Buchanan)+ + - - -

Catla catla (Hamilton) - - + + +Laubuca laubuca (Hamilton) - - + + +Cirrhinus mrigala (Hamilton) - - + + +C. reba (Hamilton) - - + + +Chagunius chagunio

(Hamilton)- - - + +

Crossocheilus latius

(Hamilton)- - + + -

Cyprinon semiplotum

(McClelland)+ + - - -

Devario devario (Hamilton) - - + + -Danio rerio (Hamilton) - - + + -Esomus danrica (Hamilton) - - + + -Garra annandalei (Hora) + - - - -Labeo bata (Hamilton) - - + + +L. calbasu (Hamilton) - - + + +L. gonius (Hamilton) - - + + +L. rohita (Hamilton) - - + + +Neolissocheilus

hexagonolepis (McClelland)+ - - - -

Ostreobrama cotio (Hamilton) - - + + -Pethia conchonius (Hamilton) - - - + +P. ticto (Hamilton) - - + + +Puntius. sophore (Hamilton) - - + + +Raimas bola (Hamilton) - + + - -Rasbora daniconius - - + + -

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(Hamilton)Salmophasia bacaila

(Hamilton)- - + + +

Nemacheilidae

Acanthocobitis botia

(Hamilton)+ + + + -

Schistura multifasciata (Day) + - - - -S. reticulofasciata (Singh &

Banarescu)+ - - - -

Cobitidae

Botia dario (Hamilton) - - + + +Canthophrys gongota

(Hamilton)- + + - -

Lepidocephalichthys

guntea (Hamilton)- - + + +

Siluriformes

Bagridae

Sperata seenghala (Sykes) - + + + +Hemibagrus menoda

(Hamilton)- + + + +

Mystus cavasius (Hamilton) - - + + +M. tengara (Hamilton) - - + + +M. vittatus (Bloch) - - + + +Rita rita (Hamilton) - - - - +

Siluridae

Ompok pabo (Hamilton) - - + + +Wallago attu (Bloch-

Schneider)- - + + +

Schilbeidae

Ailia coila (Hamilton) - + + + -Clupisoma garua (Hamilton) - - - + +Eutropiichthys

vacha (Hamilton)- + + + -

Neotropius

atherinoides (Bloch)- - + + +

PangasiidaePangasius

pangasius (Hamilton)- - - - +

SisoridaeGagata cenia (Hamilton) - - + + -Bagarius bagarius (Hamilton) - - + + +

OlyridaeOlyra longicaudata

(McClelland)+ - - - -

Perciformes Ambassidae Chanda nama (Hamilton) - + + + +Parambassis ranga

(Hamilton)

- + + + +

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Anabantidae Anabus testudineus (Bloch) - - + + +

Osphronemidae

Trichogaster fasciata (Bloch

& Schneider)- - + + +

T. lalius (Hamilton) - - + + +P. chuna (Hamilton) - - + + +

Channidae

Channa gachua (Hamilton) - - + + +C. punctata (Bloch) - - + + +C. Stewartii (Playfair) - - + + +C. striata (Bloch) - - + + +

GobiidaeGlossogobius giuris

(Hamilton)- + + + +

Beloniformes BelonidaeXenontodon cancila

(Hamilton)- - + + +

Synbrachiformes Mastacembelidae

Macrognathus aral (Bloch &

Schneider) - - + + +

M. pancalus (Hamilton) - - + + +Mastacembelus

armatus (Lacepède)- - + + +

Cyprinodontiformes AplochelidaeAplocheilus panchax

(Hamilton)- - + + +

Note: + present, - Absent

Table-43: An account of station wise occurrence of Fish species in Pagladia river

An account of station wise occurrence of the fish species revealed that only nine

species of fish was reported from station-1 (minimum), 13 species were reported from

station-2, 57 were species reported from station-3, 58 were species reported from

station-4 (maximum) and 50 were species reported from station-5.

An account of station and family wise occurrence of the fish species is presented

below-

1. Notopteridae: Two fish species belonging to this family recorded from Pagladia

river. Species like Chitala chitala and Notopterus notopterus were reported from

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station-3, 4 and 5. These two species are plain water forms and inhabit in the

down stream zones of the tributary.

2. Cyprinidae: Cyprinidae represented maximum number (30) of fish species from

Pagladia river. Fish species like Amblypharygodon mola, Aspidoparia jaya, A.

morar, Barilius barila, B. bendelisis, Catla catla, Laubuca laubuca, Cirrhinus

mrigala, C. reba, Labeo bata , L. calbasu, L. gonius, L. rohita, Pethia ticto

Salmophasia bacaila were collected from station-3, 4 and 5. On the other hand

species like Bangana dero, Barilius vagra and Cyprinon semiplotum were

reported from station-1 and 2. Crossocheilus latius, Devario devario, Danio

rerio, Esomus danrica, Ostreobrama cotio and Rasbora daniconius were

reported from station-3 and 4. Raimas bola collected from station-2 and 3.

Chagunius chagunio and Pethia conchonius were reported from station-4 and 5.

Garra annandalei and Neolissocheilus hexagonolepis were only reported from

station-1.

3. Nemacheilidae: Nemacheilidae represented only three fish species from

Pagladia river. Among these species Acanthocobitis botia repoted from station-

1, 2, 3 and 4 and other two species i.e. Schistura multifasciata and S.

reticulofasciata were reported from only station-1.

4. Cobitidae: Cobitidae represented only three fish species from Pagladia river.

Among these fish species Canthophrys gongota was reported from station-2 and

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3, while remaining two species i.e. Botia dario Lepidocephalichthys guntea and

were reported from station-3, 4 and 5.

5. Bagridae: Six fish species belonging to this family were recorded from Pagladia

river. Among all these fishes Sperata seenghala and Hemibagrus menoda were

reported from station-2, 3, 4 and 5. Species like Mystus cavasius, M. tengara

and M. vittatus were reported from station-3, 4 and 5. Rita rita was the species

collected only from station-1.

6. Siluridae: Two fish species belonging to this family were reported from

Pagladia river. These two species i.e. Ompok pabo and Wallago attu were

collected from station-3, 4 and 5.

7. Schilbeidae: Four fish species belonging to this family were recorded from

Pagladia river. Among these species Ailia coila and Eutropiichthys vacha were

reported from station-2, 3 and 4. Clupisoma garua was reported from station-4

and 5. Neotropius atherinoides was reported from station-3, 4 and 5.

8. Pangasiidae: Only one species of this family namely Pangasius pangasius was

reported from only station-5 of this tributary.

9. Sisoridae: Two species of this family namely Gagata cenia and Bagarius

bagarius were recorded from Pagladia river. The first one reported from station-

3 & 4, while the second one reported from station-3, 4 and 5.

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10. Olyridae: Only one species of this family namely Olyra longicaudata was

reported from only station-1 of this tributary.

11. Ambassidae: Two species of this family namely Chanda nama and

Parambassis ranga were recorded from Pagladia river. Both these two species

were collected from station-2, 3, 4 and 5.

12. Anabantidae: Only one species of this family namely Anabus testudineus was

reported from station-3, 4 and 5 of this tributary.

13. Osphronemidae: Three fish species namely Trichogaster fasciata, T.

lalius and P. chuna belonging to family Osphronemidae were recorded from

Pagladia river. All these three species were reported from station-3, 4 and 5.

14. Channidae: Channidae represented four fish species from Pagladia river. All

these four species namely Channa gachua, C. punctata , C. Stewartii and C.

striata were reported from station-3, 4 and 5.

15. Gobiidae: Only one species of this family namely Glossogobius giuris was

reported from station-2, 3, 4 and 5 of this tributary.

16. Belonidae: Single species of this family namely Xenontodon cancila was

reported from station-3, 4 and 5 of this tributary.

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17. Mastacembelidae: Three species of this family namely Macrognathus aral, M.

pancalus and Mastacembelus armatus were recorded from Pagladia river. All

these three species reported from station-3, 4 and 5.

18. Aplochelidae: Single species of family Aplochelidae namely Aplocheilus

panchax was reported from station-3, 4 and 5 of this tributary.

8.2.1 Fish species richness and diversity indices:

Species richness, abundance and diversity of a particular area directly correlated

with the environmental features of that area. As these parameters fluctuate in each

season of the year a seasonal variation is also observed in species richness, abundance

and diversity. During the study period seasonal as well as altitudinal variation in species

richness, abundance and diversity were observed in Pagladia river. All the results have

been discussed below-

Station-1:

During year 2009, species abundance was ranged between 6 and 107 minimum

during monsoon and maximum in winter. Species richness was ranged between 3 and 9

minimum during monsoon and maximum in remaining three seasons. Shannon-Weiner

index (H/) was ranged between 1.11 and 2.14 minimum during monsoon and maximum

in pre-monsoon. Simpson’s index of dominance (D) was ranged between 0.12 and 0.33

minimum during pre-monsoon and maximum in monsoon. Simpson’s index of diversity

was ranged between 0.69 and 0.88 minimum during monsoon and maximum in pre-

176

monsoon. Evenness (E) was ranged between 0.94 and 1 minimum during retreating

monsoon and maximum in monsoon.

Similarly during year 2010, species abundance was ranged between 8 and 111

minimum during monsoon and maximum in winter. Species richness was ranged

between 4 and 9 minimum during monsoon and maximum in remaining three seasons.

Shannon-Weiner index (H/) was ranged between 1.32 and 2.31 minimum during

monsoon and maximum in pre-monsoon and reatreating monsoon. Simpson’s index of

dominance (D) was ranged between 0.12 and 0.28 minimum during pre-monsoon and

maximum in monsoon. Simpson’s index of diversity was ranged between 0.72 and 0.88

minimum during monsoon and maximum in pre-monsoon. Evenness (E) was ranged

between 0.93 and 0.95 minimum during winter and maximum in pre-monsoon.

Station-2:

During year 2009, species abundance was ranged between 20 and 79 minimum

during monsoon and maximum in winter. Species richness was ranged between 8 and

13 minimum during monsoon and maximum in winter. Shannon-Weiner index (H/) was

ranged between 1.97 and 2.40 minimum during monsoon and maximum in winter.

Simpson’s index of dominance (D) was ranged between 0.11 and 0.15 minimum during

pre-monsoon and winter and maximum in monsoon. Simpson’s index of diversity was

ranged between 0.85 and 0.89 minimum during monsoon and maximum in pre-

monsoon and winter. Evenness (E) was ranged between 0.83 and 0.90 minimum during

retreating monsoon and maximum in pre-monsoon and monsoon.



177

between 8 and 13 minimum during monsoon and maximum in winter. Shannon-Weiner

index (H/) was ranged between 1.97 and 2.40 minimum during monsoon and maximum

in winter. Simpson’s index of dominance (D) was ranged between 0.11 and 0.15

minimum during pre-monsoon and maximum in monsoon. Simpson’s index of diversity

was ranged between 0.85 and 0.89 minimum during monsoon and maximum in pre-

monsoon. Evenness (E) was ranged between 0.83 and 0.92 minimum during retreating

monsoon and maximum in pre-monsoon.

Station-3:

During year 2009, species abundance was ranged between 503 and 874

minimum during pre-monsoon and maximum in winter. Species richness was ranged

between 54 and 57 minimum during monsoon and maximum in remaining three

seasons. Shannon-Weiner index (H/) was ranged between 3.77 and 3.93 minimum

during monsoon and maximum in pre-monsoon. Simpson’s index of dominance (D) was

ranged between 0.02 and 0.03 minimum during retreating monsoon and maximum in

monsoon. Simpson’s index of diversity was ranged between 0.97 and 0.98 minimum

during monsoon and maximum in remaining all seasons. Evenness (E) was ranged

between 0.80 and 0.89 minimum during monsoon and maximum in retreating monsoon.


minimum during pre-monsoon and maximum in winter. Species richness was ranged

between 54 and 57 minimum during monsoon and maximum in all seasons other than

monsoon. Shannon-Weiner index (H/) was ranged between 3.78 and 3.95 minimum

during monsoon and maximum in retreating monsoon. Simpson’s index of dominance

(D) was ranged between 0.02 and 0.03 minimum during all seasons other than monsoon

178

and maximum in monsoon. Simpson’s index of diversity was ranged between 0.97 and

0.98 minimum during monsoon and maximum in all seasons other than monsoon.

Evenness (E) was ranged between 0.82 and 0.91 minimum during monsoon and

maximum in retreating monsoon.

Station-4:


minimum during retreating monsoon and maximum in winter. Species richness was

ranged between 53 and 58 minimum during monsoon and maximum in pre-monsoon.

Shannon-Weiner index (H/) was ranged between 3.78 and 3.87 minimum during winter

and maximum in pre-monsoon and retreating monsoon. Simpson’s index of dominance

(D) was ranged between 0.02 and 0.03 minimum during pre-monsoon, monsoon and

retreating monsoon and maximum in winter. Simpson’s index of diversity was ranged

between 0.97 and 0.98 minimum during winter and maximum in remaining seasons.

Evenness (E) was ranged between 0.78 and 0.86 minimum during winter and maximum

in retreating monsoon.


minimum during retreaeting monsoon and maximum in winter. Species richness was

ranged between 53 and 58 minimum during monsoon and maximum in pre-monsoon.

Shannon-Weiner index (H/) was ranged between 3.78 and 3.90 minimum during winter

and maximum in retreating monsoon. Simpson’s index of dominance (D) was estimated

equal in all seasons (0.02). Simpson’s index of diversity was ranged between 0.97 and

0.98 minimum during winter and maximum in all seasons other than winter. Evenness

179

(E) was ranged between 0.79 and 1 minimum during winter and maximum in monsoon

and retreating monsoon.

Station-5:



between 3 and 9 minimum during monsoon and maximum in pre-monsoon, winter and

retreating monsoon. Shannon-Weiner index (H/) was ranged between 1.11 and 2.14

minimum during monsoon and maximum in pre-monsoon. Simpson’s index of

dominance (D) was ranged between 0.12 and 0.33 minimum during pre-monsoon and

maximum in monsoon. Simpson’s index of diversity was ranged between 0.69 and 0.88

minimum during monsoon and maximum in pre-monsoon. Evenness (E) was ranged

between 0.94 and 1 minimum during retreating monsoon and maximum in monsoon.


minimum during retreating monsoon and maximum in winter. Species richness was

ranged between 47 and 50 minimum during monsoon and winter and maximum in pre-

monsoon and retreating monsoon. Shannon-Weiner index (H/) was ranged between 3.60

and 3.78 minimum during winter and maximum in retreating monsoon. Simpson’s

index of dominance (D) was estimated equal in all seasons (0.03). Simpson’s index of

diversity was ranged between 0.97 and 0.98 minimum in all seasons other than

retreating monsoon and maximum in monsoon retreating monsoon. Evenness (E) was

ranged between 0.78 and 0.87 minimum during winter and maximum in retreating

monsoon.

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Seasons

Index

Number of

individuals

(N) (Species

Abundance)

Number

of species

(Richness)

(S)

Species

diversity

(H/)

Simpson’s diversity

indices

Evenness

(E)

Simpson’s

index of

dominance

(D)

Simpson’s

index of

diversity

(1 – D)

Pre-

monsoon

1 46 9 2.14 0.12 0.88 0.95

2 36 11 2.30 0.11 0.89 0.903 503 57 3.92 0.02 0.98 0.884 530 58 3.87 0.02 0.98 0.82

181

Stat

ions

5 461 50 3.74 0.03 0.97 0.84

Monsoon

1 6 3 1.10 0.33 0.67 1

2 20 8 1.97 0.15 0.85 0.903 509 54 3.77 0.03 0.97 0.804 566 53 3.81 0.02 0.98 0.855 477 46 3.68 0.03 0.98 0.86

Retreating

monsoon

1 46 9 2.13 0.13 0.87 0.94

2 37 12 2.30 0.12 0.88 0.833 534 57 3.93 0.02 0.98 0.894 506 57 3.87 0.02 0.98 0.865 437 50 3.78 0.03 0.98 0.87

Winter

1 107 9 2.13 0.13 0.87 0.97

2 79 13 2.40 0.11 0.89 0.843 874 57 3.92 0.02 0.98 0.884 768 56 3.78 0.03 0.97 0.785 652 57 3.60 0.03 0.97 0.78

Table-44: Species richness and diversity indices of Fish fauna in Pagladia river

during 2009

Seasons

Index

Number of

individuals

(N) (Species

Abundance)

Number

of species

(Richness)

Species

diversity

(H/)

Simpson’s diversity

indices

Evenness

(E)

Simpson’s

index of

dominance

D

Simpson’

s index of

diversity

1 – D

Pre-

monsoon

1 48 9 2.15 0.12 0.88 0.952 40 11 2.31 0.11 0.89 0.923 532 57 3.93 0.02 0.98 0.904 534 58 3.87 0.02 0.98 0.835 475 50 3.75 0.03 0.97 0.85

Monsoon

1 8 4 1.32 0.28 0.72 0.942 20 8 1.97 0.15 0.85 0.903 627 54 3.78 0.03 0.97 0.824 575 53 3.81 0.02 0.98 0.865 488 47 3.69 0.03 0.97 0.85

Retreatin

g

1 46 9 2.13 0.13 0.87 0.942 37 12 2.31 0.12 0.88 0.833 563 57 3.95 0.02 0.98 0.914 515 57 3.90 0.02 0.98 0.86

182

Stat

ions

monsoon 5 439 50 3.78 0.03 0.98 0.87

Winter

1 111 9 2.13 0.13 0.87 0.932 84 13 2.40 0.10 0.90 0.853 937 57 3.94 0.02 0.98 0.904 772 56 3.78 0.03 0.97 0.795 660 47 3.60 0.03 0.97 0.78

Table-45: Species richness and diversity indices of fish fauna in Pagladia river

during 2010

8.2.2 Bray-Curtis Cluster Analysis

Cluster analysis of the survey stations made based on the abundance of fish

fauna in the survey stations (Fig-43 and 44) revealed a comparable picture.

During 2009 as the number of individuals of fish fauna in the station-1 and 2

were less (205 and 172 respectively), it was farthest from all the clusters in the

dendrogram. Sites 3 and 4 were more closely positioned and comparatively nearer to

station-5 than station-1 and 2.

183

Fig-43: Bray-Curtis Cluster analysis using simple linkage method for five survey

stations in Pagladia river during 2009

Similarly during 2010 as the number of individuals of fish fauna in the station-1

and 2 were less (213 and 181 respectively), it was farthest from all the clusters in the

dendrogram. Sites 3 and 4 were more closely positioned and comparatively nearer to

station-5 than station-1 and 2.

184

Fig-44: Bray-Curtis Cluster analysis using simple linkage method for five survey

stations in Pagladia river during 2010

8.2.3 Principal Component Analysis (PCA)

It is evident from the PCA as represented in Fig. 45 and 46, that relative distance

between the two survey stations indicates the similarity between them and respective

coordinates.

185

Fig-45: Biplot of principal component derived from in the five survey station on

Fish species richness and their ecological status during 2009

Fig-46: Biplot of principal component derived from in the five survey station on

Fish species richness and their ecological status during 2010

186

8.3 Ornamental Fish Categories:

Many of the fish species reported from five stations of Pagladia river (87.14%)

are considered as ornamental fish. Out of these 70 fish species recorded from Pagladia,

61 species were recognized as ornamental fish, of which 35 species identified as

classified and 26 as non-classified ornamental fish, which are depicted in Table-46.

Sl. No. Name of the species Category1 Chitala chitala (Hamilton) Non-classified2 Notopterus notopterus (Pallas) Non-classified3 Amblypharygodon mola (Hamilton) Classified4 Aspidoparia jaya (Hamilton) Classified5 A. morar (Hamilton-Buchanan) Non-classified6 Barilius barila (Hamilton) Classified7 B. bendelisis (Hamilton) Classified8 B. vagra (Hamilton- Buchanan) Classified9 Laubuca laubuca (Hamilton) Classified10 Cirrhinus reba (Hamilton) Non-classified11 Chagunius chagunio (Hamilton) Classified12 Crossocheilus latius (Hamilton) Non-classified13 Cyprinon semiplotum (McClelland) Non-classified14 Devario devario (Hamilton) Classified15 Danio rerio (Hamilton) Classified16 Esomus danrica (Hamilton) Classified17 Garra annandalei (Hora) Non-classified18 Labeo calbasu (Hamilton) Non-classified19 Neolissocheilus hexagonolepis (McClelland) Non-classified20 Ostreobrama cotio (Hamilton) Classified21 Pethia conchonius (Hamilton) Classified22 P. ticto (Hamilton) Classified23 Puntius. sophore (Hamilton) Classified24 Raimas bola (Hamilton) Non-classified25 Rasbora daniconius (Hamilton) Classified26 Salmophasia bacaila (Hamilton) Non-classified27 Acanthocobitis botia (Hamilton) Classified28 Schistura multifasciata (Day) Classified29 S. reticulofasciata (Singh & Banarescu) Classified30 Botia dario (Hamilton) Classified31 Canthophrys gongota (Hamilton) Non-classified32 Lepidocephalichthys guntea (Hamilton) Classified33 Hemibagrus menoda (Hamilton) Non-classified34 Mystus cavasius (Hamilton) Non-classified

187

35 M. tengara (Hamilton) Classified36 M. vittatus (Bloch) Classified37 Rita rita (Hamilton) Non-classified38 Ompok pabo (Hamilton) Non-classified39 Ailia coila (Hamilton) Non-classified40 Clupisoma garua (Hamilton) Classified41 Eutropiichthys vacha (Hamilton) Non-classified42 Neotropius atherinoides (Bloch) Classified43 Pangasius pangasius (Hamilton) Non-classified44 Gagata cenia (Hamilton) Classified45 Olyra longicaudata (McClelland) Classified46 Chanda nama (Hamilton) Classified47 Parambassis ranga (Hamilton) Classified48 Anabus testudineus (Bloch) Non-classified49 Trichogaster fasciata (Bloch & Schneider) Classified50 T. lalius (Hamilton) Classified51 P. chuna (Hamilton) Classified52 Channa gachua (Hamilton) Classified53 C. punctata (Bloch) Non-classified54 C. Stewartii (Playfair) Non-classified55 C. striata (Bloch) Non-classified56 Glossogobius giuris (Hamilton) Non-classified57 Xenontodon cancila (Hamilton) Non-classified58 Macrognathus aral (Bloch & Schneider) Classified59 M. pancalus (Hamilton) Classified60 Mastacembelus armatus (Lacepède) Non-classified61 Aplocheilus panchax (Hamilton) Classified

Table-46: Category of Ornamental Fish Species (OFS) in Pagladia river

8.4 Threat categories

Out of these 70 fish species recorded from Pagladia river, 61 species were

assessed as least concern (LC), 6 near threatened (NT), 2 vulnerable (VU) and 1 data

deficient (DD).The list of fish species recorded from Pagladia along with their threat

status as per IUCN (2012.2) is depicted in Table-47.

Sl. No. Name of the species Threat Category1 Chitala chitala (Hamilton) NT2 Notopterus notopterus (Pallas) LC3 Amblypharygodon mola (Hamilton) LC4 Aspidoparia jaya (Hamilton) LC5 A. morar (Hamilton-Buchanan) LC

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6 Bangana dero (Hamilton) LC7 Barilius barila (Hamilton) LC8 B. bendelisis (Hamilton) LC9 B. vagra (Hamilton- Buchanan) LC10 Catla catla (Hamilton) LC11 Laubuca laubuca (Hamilton) LC12 Cirrhinus mrigala (Hamilton) LC13 C. reba (Hamilton) LC14 Chagunius chagunio (Hamilton) LC15 Crossocheilus latius (Hamilton) LC16 Cyprinon semiplotum (McClelland) VU17 Devario devario (Hamilton) LC18 Danio rerio (Hamilton) LC19 Esomus danrica (Hamilton) LC20 Garra annandalei (Hora) LC21 Labeo bata (Hamilton) LC22 L. calbasu (Hamilton) LC23 L. gonius (Hamilton) LC24 L. rohita (Hamilton) LC25 Neolissocheilus hexagonolepis (McClelland) NT26 Ostreobrama cotio (Hamilton) LC27 Pethia conchonius (Hamilton) LC28 P. ticto (Hamilton) LC29 Puntius sophore (Hamilton) LC30 Raimas bola (Hamilton) LC31 Rasbora daniconius (Hamilton) LC32 Salmophasia bacaila (Hamilton) LC33 Acanthocobitis botia (Hamilton) LC34 Botia dario (Hamilton) LC35 Canthophrys gongota (Hamilton) LC36 Schistura multifasciata (Day) LC37 S. reticulofasciata (Singh & Banarescu) VU38 Lepidocephalichthys guntea (Hamilton) LC39 Sperata seenghala (Sykes) LC40 Hemibagrus menoda (Hamilton) LC41 Mystus cavasius (Hamilton) LC42 M. tengara (Hamilton) LC43 M. vittatus (Bloch) LC44 Rita rita (Hamilton) LC45 Ompok pabo (Hamilton) NT46 Wallago attu (Bloch- Schneider) NT47 Ailia coila (Hamilton) NT48 Clupisoma garua (Hamilton) LC49 Eutropiichthys vacha (Hamilton) LC50 Pangasius pangasius (Hamilton) LC51 Neotropius atherinoides (Bloch) LC

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52 Gagata cenia (Hamilton) LC53 Bagarius bagarius (Hamilton) NT54 Olyra longicaudata (McClelland) LC55 Chanda nama (Hamilton) LC56 Parambassis ranga (Hamilton) LC57 Anabus testudineus (Bloch) DD58 Trichogaster fasciata (Bloch & Schneider) LC59 T. lalius (Hamilton) LC60 T. chuna (Hamilton) LC61 Channa gachua (Hamilton) LC62 C. punctata (Bloch) LC63 C. Stewartii (Playfair) LC64 C. striata (Bloch) LC65 Glossogobius giuris (Hamilton) LC66 Xenontodon cancila (Hamilton) LC67 Macrognathus aral (Bloch & Schneider) LC68 M. pancalus (Hamilton) LC69 Mastacembelus armatus (Lacepede) LC70 Aplocheilus panchax (Hamilton) LC

Table-47: Threat Category of different Fish species in Pagladia river as per IUCN

(2012.2)

Fig-:Threat status of fish fauna of Pagladia river as per IUCN (2012)

87%

9%

3%

1%

Least concern (LC)Near threatened (NT)vulnerable (VU)Data deficient (DD)

Fig-47: Percentage contribution of threat category of Fish species in Pagladia river

as per IUCN (2012.2)

8.5 Seasonal landing of fish

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The main fishing seasons in Pagladia river was found to be winter, pre-monsoon

and retreating monsoon as during this period water level of the stream recedes. Fish

caught is very low in monsoon season due to high water level and fast water current.

Table- shows the order-wise fish catch composition (in percentage) in the Pagladia river

during the present study period. Cypriniformes constituted about highest percent (57.79

%) of the total annual fish catch. Similarly, Cyprinodontiformes constituted lowest

percentage (0.17 %) of total annual fish catch.

There is no definite and regular fish landing stations near the banks of Pagladia

river. Fishes caught from this tributary sometimes brought to the local market for sale.

But in most of the cases, the catch is sold in some unorganized temporary markets near

road side and river bank. During fishing seasons, the catch is mainly dominated by fish

species like Labeo rohita , Neolissocheilus hexagonolepis, Raimas bola, Catla, catla,

Salmophasia bacaila, Cyprinon semiplotum, Amblypharygodon mola, Barilius barila,

B. bendelisis, Puntius. sophore, Raimas bola, Sperata seenghala , Mystus cavasius , M.

vittatus, Wallago attu and Mastacembelus armatus.

Order PM M RM W AnnualOsteoglossiformes 27.02 % 16.21 % 28.37 % 28.37 % 10.99 %

Cypriniformes 30.84 % 8.74 % 32.13 % 28.27 % 57.79 %Siluriformes 30.53 % 9.16 % 31.29 % 29.0 % 19.46 %Perciformes 32.43 % 13.51 % 29.72 % 24.32 % 5.50 %

Beloniformes 33.33 % 8.33 % 33.33 % 25.0 % 1.78 %Synbrachiformes 27.58 % 20.68 % 24.13 % 27.58 % 4.31 %

Cyprinodontiformes 43.47 % 4.34 % 26.08 % 26.08 % 0.17 %

Table-48: Seasonal and annual fish catch (%) of different orders of fish from

Pagladia river

8.6 Effects of hydrobiological parameters on fish population:

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8.6.1 Effect of physico-chemical parameters of water on Fish abundance:

From the result it becomes clear that except transparency and water depth all

other physico-chemical parameters are correlated with the fish abundance. Among these

temperature (r = 0.22), pH (r = 0.31), free carbon-dioxide (r = 0.17), total alkalinity (r =

0.43) and total chloride (r = 0.37) are positively correlated and parameters like water

velocity (r = -0.66), dissolved oxygen (r = -0.36), total hardness (r = -0.10) are

negatively correlated with fish species abundance.

Canonical Correspondence Analysis (CCA) was applied to evaluate the various

physico-chemical parameters on fish abundance. From the ordination diagram it

becomes clear that commonly occurring families of fishes occupies the central position

of the ordination graph and the families with rare occurrence seen at the position distant

from the centre. For example, families like Cyprinidae, Schilbeidae, Sisoridae,

Anabantidae, Osphronemidae, Channidae, Mastacembelidae and Aplochelidae occupies

the central position of the ordination plot (Fig-48).

Family Pangasiidae, Sissoridae and Gobiidae show positive correlation with

temperature. This clearly suggests that fishes of these families were abundantly reported

from sites with high temperature. Similarly family Notopteridae, Siluridae and

Mastacembelidae show positive correlation with TA and TC. It also indicates that

physico-chemical parameters of water like total alkalinity and total chloride has

influence on the distribution of fish families like Notopteridae, Siluridae and

Mastacembelidae and species of such families were abundantly collected from sites

with high TA and TC. All the fish species of family Gobiidae, Schilbeidae, Olyridae,

Cyprinidae show positive correlation with water velocity, dissolved oxygen and TH.

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This clearly suggests the fishes of such families prefer habitats with high dissolved

oxygen content, water velocity and total hardness.

Fig-48: Spatial ordination resulting from CCA of Fish abundance of Pagladia river

with respect to physico-chemical parameters of water

8.6.2 Effect of Zooplankton density on Fish abundance:

The CCA of fish abundance with zooplankton density as constrains revealed that

Cladocera, Ostracoda and Rotifera are positively correlated with families like

Cyprinidae, Schilbeidae, Sisoridae, Anabantidae, Osphronemidae, Mastacembelidae,

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Aplochelidae, Nemacheiladae and Ambassidiae (Fig-49). This suggests the growth of

these families may have a direct correlation with density of Cladocera, Ostracoda and

Rotifera. Higher density of Cladocera, Ostracoda and Rotifera may favour the growth of

these fishes which may be due to its feeding habit. On the other hand, ordination

diagram also revealed that, zooplankton group like Copepoda is positively correlated

with families like Pangasiidae, Belonidae and Channidae. This suggests that the

abundance of such families of fishes may be directly influenced by the density of

Copepoda.


with respect to Zooplankton density

8.6.2 Effect of phytoplankton density on fish abundance

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The CCA of fish abundance with phytoplankton density as constrains revealed

that Chlorophyceae and Bacillariophyceae are positively correlated with families like

Olyridae, Notopteridae, Belonidae and Mastacembelidae (Fig-50). This suggests the

growth of these families may have a direct correlation with density of Chlorophyceae

and Bacillariophyceae. Higher density of Chlorophyceae and Bacillariophyceae may

favour the growth of these fishes which may be due to its feeding habit.

On the other hand, ordination diagram also revealed that, phytoplankton group

like Dinophyceae and Cyanophyceae are positively correlated with families like

Cyprinidae, Cobitidae, Ambassidae, Bagridae, Schilbeidae, Nemacheiladae. This

suggests that the abundance of such families of fishes may be directly influenced by the

density of Dinophyceae and Cyanophyceae.

Similarly, the phytoplankton group Euglenophyceae is positively correlated with

families like Anabantidae, and Aplochelidae. This clearly suggests that abundance of

Euglenophyceae may favour the growth of fish families like Anabantidae, and

Aplochelidae.

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with respect to Phytoplankton density

8.6.4 Effect of periphyton density on fish abundance:

The CCA of fish abundance with periphyton density as constrains revealed that

Cyanophyceae is positively correlated with families like Schilbeidae, Cobitidae,

Bagridae, Ambassidae and Anabantidae (Fig-51). This suggests the growth of these

families may have a direct correlation with density of Cyanophyceae. Higher density of

Cyanophyceae may favour the abundance of these fishes which may be due to its

feeding habit. Similarly periphyton groups like Chlorophyceae and Bacillariophyceae

are directly correlated with fish families like Gobiidae, Nemacheilidae, Olyridae and

Mastacembelidae. This suggests that abundance of these families may be directly

influenced by the density of these two periphyton groups.

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with respect to Periphyton density

8.7 Fishing Methods

Selection of fishing methods and gear are influenced by various factors such as

physiography of the water body, nature of fish stock, characteristics of raw material

from which gears are fabricated (Choudhury, 1992). The earliest record of conventional

fishing gears and their mode of operation were made by Day (1877). Subsequently, the

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fishing gears of the inland waters were reported by Job and Pantalu (1958) and Joseph

and Narayan (1965). Bhagawati and Kalita (1987) studied the traditional fishing

methods in some beels of Kamrup district, Assam. While Yadav et al. (1981) and

Yadava and Choudhury (1986) accounted the special devices used in the floodplain

lakes of Brahmaputa river. Recently, Barua et al. (2010) reported the traditional fishing

gears of the Brahmaputa valley.

8.6.1. Common fishing gears used in fishing:

Various kinds of nets and fishing traps are used in Pagladia River for fishing.

The common fishing gears operated in Pagladia are as follows-

1. Cast net (Asra jal): It is a large casting type of net which is used to catch

large and medium sized fishes. It is made up of cotton or nylon thread and its

body is bell shaped. The rim of the net is the widest part and it tapers

gradually towards the apex. The rim is folded inside by 5-10 inches, the

margin of which is tied with the body of the net at a regular distance of 3-4

inches to give bag like structure, each knot consisting of a pair of iron or lead

beads. It is mostly used throughout the year in the Pagladia River.

2. Gill net: These are rectangular gill nets fitted with head rope and foot rope.

The head rope is attached to floats and foot rope is made thicker with heavy

ropes. It is generally used to catch large fishes. Mild water current is

beneficial for this operation. The net is mostly operated during seasons other

than monsoon.

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3. Scoop net (Thela jal): It is a hand net with or without frame. This net is

usually operated in shallow water during winter season in this tributary. The

fishers dips the net in the water and pushes it forward for a certain distance

and thereafter lifts it to catch the fishes accumulated in the net. Small fishes

and prawn are the main catch.

4. Drag net: It is a rectangular drag net having on the hand rope and sinkers on

the foot rope. Bag like appendages are attached at the bottom of the net. The

net is dragged usually by two persons in the pond with the help of the hand

ropes from deeper areas to the shore. The fishes are concentrated in the bags.

The net is mostly operated during the winter months.

5. Chinese dip net (Parangi jal): The mesh size of the net ranges from 10-20

mm. The net is portable, small and light weight; hence children and women

can operate it easily. It is used to catch small fishes during monsoon season.

6. Dip net/Lift net (Dheki jal): It is small as that of Chinese dip net, but with

bigger mesh size and fitted to a triangular bamboo frame with the narrow

end placed near the operator. Indigenous bamboo lever is used to lift the net.

The operator stands over the lever to periodically lift the net. The net is set in

the flowing water against the water current during monsoon season.

199

7. Line fishing: The technology of line fishing is that fishes are attracted by

real or artificial bait in a hook. The hook is pierced through the mouth, when

fishes start taking the bait. Thus fishes are caught.

8. Different fishing traps such as basket trap:

a. Juluki: Bamboo strips are laced together to make this cylindrical cover

basket. It has wide opening on the top. Usually the adjacent split bamboo

strips have comparatively lesser gaps in between. On the top portion, there is

a gap to handle easily. It is mainly operated during winter season in this

tributary.

b. Polo: Round bamboo strips are laced together by cane or plastic strips to

make this bell shaped cover basket. It has narrow opening on the top. The

gear is quickly plunged in shallow water from above when fishes get

encircled in the small basket; they are manually caught and removed through

the narrow hole on the top.

8.6.2. Traditional methods of Fishing

Apart from these fishing gears, the local people practice certain unique methods

at Pagladia.

Diversification of river channels is a common traditional methods practiced at

this tributary. This method is occasionally used in Pagladia River for which the river is

made dry, deflecting the flow of water to one of the either side from the main riverbed

200

by constructing a rough stone dam. At the distal end of diverted channel a bamboo fish

trap is set so as to catch the fish escaped from the main river. The blocking is made by

using stones, logs, sand, branches of trees and clay. The fish are caught with bare hands

or with the help of scoop nets.

8.6.3. Destructive fishing:

Apart from the above mentioned methods, the local people using pesticides and

chemicals for fishing. Blasting is another destructive method of fishing in hill stream

regions of the tributary.

8.7. Discussion

The result of present study revealed the occurrence of 70 fish species belonging

to 53 genera, 18 families and 7 orders. Previously Dey (1973) reported 51 freshwater

fish species from this tributary. During the study period the order Cypriniformes was

dominant over other orders of fish and has been recorded from the five sampling sites in

the Pagladia river. The Cyprinidae family was found to be the most dominant group

among all the families. The results are in accordance with those of Wakid and Biswas

(2005), Bhat (2003) and Shahnawaz et al. (2009).

Species abundance recorded as maximum 937 in winter at station-3 during 2010

and minimum 6 in monsoon during 2009. The Shannon-Weiner fish diversity index of

different sites of River Pagladia was ranged from 3.90 (maximum in retreating monsoon

at station-4 during 2010) to 1.10 (minimum in monsoon at station-1 during 2009).

Species richness was recorded maximum 58 in pre- monsoon during 2009 and 2010 at

station-4 and minimum 3 in monsoon at station-1 during 2009. This indicates good

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correlation with overall species richness across the sites and could be utilized by the

biodiversity conservation managers for prioritization of sites of conservation and habitat

restoration (Bergerot et al., 2008).

There is no regular and definite fish landing stations in Pagladia river. Fishes

caught from Pagladia river sometimes brought to the local market for sale. But in most

of the cases, the catch is sold in some unorganized markets near road side and river

bank. Fishing operations were carried out for nine months with low in monsoon

compared to high in retreating monsoon.

Different fishing methods used in the Pagladia river and their impacts revealed,

that the observed fishing methods can be classified into two categories, namely, (a)

Scientific fishing method, that is, collection of required number and size of fish so that

sufficient population of fish remain balanced in the nature, examples being, cast netting

and angling and (b) Unscientific fishing method, involves indiscriminate killing of large

number of fish (juvenile, as well as, brood fish) which adversely affects the water

quality of rivers, for example, (1) Blasting , (2) River poisoning and (5) Diversion of

river channel.

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