Catfish
(Teleostei: Siluriformes) diversity in Karala River of Jalpaiguri District,
West Bengal, India
Amal Kumar Patra
Department of Zoology, Ananda
Chandra College, Jalpaiguri, West Bengal 735101, India
Email: amalpatra@yahoo.co.in
Date of
publication (online): 26 March 2011
Date of
publication (print): 26 March 2011
ISSN
0974-7907 (online) | 0974-7893 (print)
Editor: W. Vishwanath
Manuscript details:
Ms # o2474
Received 30 May 2010
Final received 20 January 2011
Finally accepted 04 February
2011
Citation: Patra, A.K. (2011). Catfish (Teleostei: Siluriformes) diversity in
Karala River of Jalpaiguri District, West Bengal, India. Journal of Threatened Taxa 3(3):
1610-1614.
Copyright: © Amal Kumar Patra 2011. Creative Commons Attribution 3.0 Unported
License. JoTT allows unrestricted use of this article in any medium for
non-profit purposes, reproduction and distribution by providing adequate credit
to the authors and the source of publication.
Acknowledgements:I am grateful to University Grant Commission
(UGC) for providing research grant; to the Principal, Ananda Chandra College
for providing me research laboratory of zoology department and others
administrative help; to the Director, Zoological Survey of India, Kolkata for
giving me an opportunity to take short course training on fresh water fish
identification under the supervision of Dr. A.K. Karmakar, Dr. S. Kar and Dr.
S.S. Mishra; to my colleagues (Dr. Tanmay Datta and Santanu Ghosh Dastidar) for
giving me valuable suggestions different times during this study.
Abstract: The diversity of fresh water catfish fauna of the Karala
River in Jalpaiguri District of West Bengal was studied from February 2009 to
January 2010. A total of seven
species belonging to six genera and six families were identified. Bagridae was
the dominant family with two representatives, whereas Amblycepitidae, Chacidae,
Olyridae, Sisoridae and Siluridae were each represented by single species.
Maximum fish diversity was recorded higher in Hakim Para (H′ =1.266) as
compared with DasPara (H′ =1.218) and Aquiduct (H′ =1.04). The
evenness index at three sampling stations indicates uneven distribution of
catfish in this tributary, possibly due to the irregular depth of river,
occurrence of submerged vegetation and physicochemical water characteristics.
Keywords: Bagridae, Catfish, Karala River, Siluriformes fishes.
For figures, images, tables -- click here
The major
riverine fishery resources of northern West Bengal are provided by the Teesta,
Torsha, Jaldhaka, Mahananda, Raidak, Sankosh, Kaljani, Korotoa, Punarbhaba and
Atrai river systems. The Teesta
originates from Jemu glacier in Sikkim and is the largest river of northern
West Bengal, passing through the districts of Darjeeling, Jalpaiguri and
Mekhliganj subdivision of Coochbehar and meeting the Brahmaputra (known as
Yamuna in Bangladesh). The main stream
is connected by several tributaries including the Karala (also known as Kalla),
which originates from the Baikunthapur forest and flows down into the Teesta
near Mandal Ghat in Jalpaiguri Town, bisecting Jalpaiguri District (located on
the confluence of river Teesta and Karala). The total catchment area is 141km2, most of which
is covered by arable land. The
basin of this river sustains life and livelihoods of tea gardeners, fishermen
and slum-dwellers.
So far as
ichthyofauna diversity in northern Bengal is concerned, the earliest report is
by Shaw & Shebbeare (1937), who reported 131 species from the rivers,
streams and ponds in the hills and plains of the Darjeeling District and the
adjoining Duars. Of these 131
species they reported 34 species of catfish. Hora & Gupta (1941) reported on a small collection of
fish from Kalimpong, Duars and Tarai, adding two species to this list. In 1977 Jayaram & Singh reported 26
species of catfish from the Tengan-Mahananda confluence, the Atrai, Purnabhasa,
Dharla (at Changrabandha), Kalindri, Mahananda (at Malda Town), Jamuna (at
Hilli Village of Balurghat), Teesta, Karotayar, Panga, Balasan and
Jaldhaka. None of these sites were
connected with the Karala River, thus the present study represents the first attempt
to study ichthyofauna diversity in this lotic system and determine fresh water
catfish resources, distribution, diversity and status on the basis of catch
frequency.
Materials and Methods
Fortnightly
fishes were captured from three different study sites (Fig. 1) of the Karala
River. Station-I (Aquiduct) is located near the origin of the river at 26047’13”N
& 88032’17”E, 122m elevation. From Jalpaiguri town its distance by bus route is 32km,
water depth is 0.4 to 0.6 m pre-and-post monsoon, rising during rain and flood
4 to 5.5 m. At station-I fish were
captured by cast net (mesh size 6x6 mm) and naphi jal (local contrivance, mesh
size 5x5 mm). Station-II is
located in the heart of the district town and behind the hospital and market
(Hakim Para) at 26031’51”N & 88043’23”E, 86m
elevation. From Jalpaiguri
District town its distance by bus route is 0.5km, regular water depth is 3.7 to
5.2 m during pre-and-post monsoon, during rain fall and flood the depth
increase to 6.6 to 7.6 m. Station-III is located at the junction of Teesta and Karala near Daspara
at 26028’42”N & 88044’27”E, 81m elevation. From Jalpaiguri district town its
distance by bus route is 7km, regular water depth is 3.7 to 4.6 m during pre-
and post-monsoon and during rain fall and flood it increases to 6.1 to 7 m. In station II and III fishes were
captured by vessel net or khara jal (local contrivance, mesh size 6x6 mm), gill
net (variable mesh sizes), and cast net (5x5 mm mesh size). Colour, colour patterns, spots etc.
were noted immediately after capture and photographs were taken by Nikon
Coolpix S4, fishes were killed by formalin solution containing one part
commercial formalin (37–40 % HCHO) + nine part glass distilled water and
7g Borax/liter (Jayaram 1981). All
samples were kept in this buffer formalin solution for 4–5 hours for
proper fixation. Catfish were segregated from the master stock and subsequently
identified by the literature of Jayaram (1999, 2006) and Talwar & Jhingran
(1991). Scientific names were confirmed from freshwater fish section of ZSI,
Kolkata.
The frequency
of occurrence of each species was calculated based on the number of occasions
the species was collected during the samplings. The status was determined with the help of a standard catch
frequency chart presented by Tamang et al. 2007 (Catch frequency 91-100 % =
Common, 81-90 = Abundant, 61-80 = Frequent, 31-59 = Occasional, 15-30=
Sporadic, 05-14= Rare and <5% = Extremely rare). Threat status and endemism were assigned following Barman
(2007). The diversity and evenness
indices were calculated according to Shannon-Weaner (1949) and Pielou
(1975). Capture of fish was done
from 0800 to 1300 hr each sampling day. The study was carried out from February 2009 to January 2010.
Results
A total
of seven species belonging to six families and six genera were collected. They
have naked skin or bony scute or plates, scales are always absent. Their oral portion contains nearly
always 1–4 pairs of barbells. The atlas, axis, 3rd and 4th vertebrae are
ossified and form a complex vertebra. An analysis of the taxonomic composition of the catfish fauna suggests
Bagridae to be the most dominant family with two representatives occurring at
SII and SIII. Amblycepitidae,
Chacidae, Olyridae, Sisoridae and Siluridae each had a single species
representation. A check list of
captured fish, local names, status (on the basis of catch frequency) and threat
status is presented in Table 1. On
the basis of catch frequency Amblyceps
mangois (Image
1) and Erethistoides
montana montana(Image 2) were common, and Olyra
longicaudata (Image
3) was abundant at upstream (SI). They were extremely rare at SII and not captured at SIII. This observation indicates that the
above three catfishes are hill stream fish representatives and prefer low
current and least water depth. TheMystus tengara(Image 4) and Chaca chaca (Image 5) are common, Wallago attu (Image 6) was occasional and Mystus bleekeri (Image 7) was rare in both SII and
SIII. The species richness in
three sampling sites of this river showed considerable variation and higher
richness was recorded in the mid to down stream. Maximum species richness was recorded from SII (Hakimpara,
total number = 06) and SIII (Daspara, total species = 04) while lower species
richness was recorded from SI (Aquiduct, total number = 03) respectively. The species diversity index of
different sampling sites was ranged from 1.04 to 1.218. In this study maximum fish diversity
was recorded higher in SII (H′ = 1.266) as compared with SIII (H′ =
1.218) and SI (H′ = 1.04) and indicates good correlation with over all
species richness across the sites. The evenness index at three sapling stations
(SI = 0.947, SII = 0.707 and SIII = 0.879) indicates uneven distribution of
catfishes in this tributary.
Discussion and Conclusions
The
knowledge of ichthyofaunal diversity, their present threat status, role in
ecosystem and human economy are prerequisites for adopting the proper
conservation strategies of fish fauna. The present study has recorded seven species of catfishes from Karala
River, a tributary of the river Teesta. In this lotic system they were distributed unevenly, down streams were
richest and more diversified than upstream. At down streams, the highest organic load occurs that cause
the productivity. Sub-merged weeds
of SII (Hakim Para) and SIII (Daspara) provide the shelter and food of fishes.
For these reasons the diversity is high. It also may be due to the heterogeneous depth of water body due to
silting, abundance of prey, substratum soil quality and physico-chemical
features of water like temperature, pH, turbidity, total solid, dissolved
oxygen, BOD etc. Three species are
threatened catfishes of India found in this river (Table 1). Among these three species, one has been
designated as Vulnerable and two have been designated as Near Threatened by
Barman (2007). The rest are data
deficient or out of danger. The only species Erethistoides montana montana Hora is
endemic to northern Bengal (Barman 2007). The cause of threatening may be due to the habitat loss, habitat
degradation, over exploitation, pollution and unscientific capture technology.
Till date
it is unfortunate that the Karala River of Jalpaiguri District has not received
any attention from the ichthyological aspects. This report gains importance as the Karala River has been described
as one of the most important tributaries of Teesta.
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