Ichthyodiversity of Periyar
Tiger Reserve, Kerala, India
K.V. Radhakrishnan 1& B. Madhusoodana Kurup 2
1 Post Doctoral Research Fellow, Key Laboratory of Ecology and Environment Science in
Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and
Safe Aquaculture, College of Life Science, South China Normal University,
Guangzhou 510631, China
2 Professor, Fisheries, School of
Industrial Fisheries, Cochin University of Science & Technology, Cochin,
Kerala 682016, India
Email: 1 krishnaradh76@gmail.com, 2 madhukurup@hotmail.com
Date of publication (online): 26
September 2010
Date of publication (print): 26 September 2010
ISSN 0974-7907 (online) | 0974-7893 (print)
Editor: Neelesh Dahanukar
Manuscript details:
Ms # o2350
Received 20 November 2009
Final received 13 August 2010
Finally accepted 20 August 2010
Citation: Radhakrishnan, K.V. & B.M. Kurup (2010).
Ichthyodiversity of Periyar Tiger Reserve, Kerala, India. Journal of Threatened Taxa 2(10): 1192-1198.
Copyright: © K.V. Radhakrishnan & B. Madhusoodana Kurup 2010.
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.
Author Details: Dr. K.V. Radhakrishnan, a freshwater fish ecologist,
completed his PhD from the School of Industrial Fisheries, Cochin University of
Science and Technology, Cochin, Kerala, India. He has a vast knowledge on the
taxonomy and ecology of freshwater fishes of Western Ghats of India.
Dr. B. Madhusoodana Kurup is a Professor and Director of School
of Industrial Fisheries in Cochin. He is a leading ichthyologist in the
country, working on various aspects of fish life history including taxonomy,
ecology, population dynamics and also conservation and sustainable utilization
of fishery resources.
Author Contribution: KVR involved in field sampling, data
analysis and prepared the manuscript. BMK assisted in field sampling and
technical guidance in data analysis.
Acknowledgements: The authors are thankful to Director, School of Industrial
Fisheries, Cochin University of Science & Technology, for providing the
necessary facilities to carry out the study. The financial assistance from the
World Bank aided National Agriculture Technology - Indian Council of
Agriculture Research Project is gratefully acknowledged. Thanks are also due to
C.P. Sunilkumar and M.D. Mahesan, who assisted in sample collection.
Abstract: Previous checklists of fishes from the Periyar Tiger
Reserve, Kerala merely included species from Periyar Lake and adjoining
streams. To fill this lacuna, we
conducted a comprehensive survey, across 10 diverse aquatic habitats within
Periyar Tiger Reserve, revealing the occurrence of 54 species belonging to six
orders and 19 families; an addition of 17 species to the previous lists. Twenty-four species found in this reserve
were listed under different threat categories. Forty-six species were found only in less than four sampling sites of
which 18 species were encountered in single location each. Nine species were very common, 10 common, 17
moderate, 12 rare and six very rare in their relative abundance. Twenty-two species are endemic to the Western
Ghats of which six species are found only in the Periyar Tiger Reserve. The Periyar river-stream system had more
number of fish species (36, 67%) than Pamba river-stream system. Among the different sampling sites, Azhutha
had both the highest number of fish species (30) and the highest number of
threatened fish species (14). The
highest number of low abundant fish species (very rare/rare) was observed at
Mlappara (7). Considering the restricted
distribution, number of endemic fishes and threat status, it is necessary to
implement urgent management plans for the conservation of freshwater fish fauna
of Periyar Tiger Reserve.
Keywords: Conservation, distribution, endemism, fish diversity,
Periyar Tiger Reserve, spatial
variation, threats.
For figures & table -- click here
INTRODUCTION
The Western Ghats of India along with
Sri Lanka is considered as one of the biodiversity hotspots of the world
(Mittermeier et al. 1998; Myers et al. 2000). The Periyar Tiger Reserve (PTR), one of the biodiversity rich areas in
southern Western Ghats from where the Periyar River originates, supports a
varied aquatic biota endowed with many endemic and threatened fish species
(Silas 1950, 1952; Zacharias et al. 1996; Kurup et al. 2004). Earliest studies on the fish fauna of the PTR
dates back to 1948 when Chacko (1948) listed 35 species from the Periyar Lake,
including the critically endangered Small Scaled Schizothoracin Lepidopygopsis typus. Later Menon & Remadevi (1995) described Hypselobarbus kurali from streams adjoining the Periyar
Lake while Menon & Jacob (1996) described Crossocheilus periyarensis and rediscovered the cyprinid, Puntius ophicephalus from Periyar River, raising the
total number of fish species to 38. Arun
et al. (1996) added six more species to the fish fauna of Periyar Lake,
including two exotic fishes, viz. Cyprinus carpio carpio and Oreochromis mossambicus, and four indigenous species, viz. Garra mcclellandi, Bhavania australis, Mesonoemacheilus guentheri and Travancoria jonesi. Additional checklist of species from PTR were prepared by Zacharias et
al. (1996) and Arun (1998) who reported
35 and 27 species respectively. Recently
Gopi (2001) described a new cyprinid, Garra periyarensis from the upstreams of Periyar, and
Kurup & Radhakrishnan (2005) described a new balitorid, Nemacheilus periyarensis from Periyar Lake.
Majority of studies on fish
distribution within PTR have been restricted to the streams of Periyar River
and Lake, and have overlooked the species of Pamba River and its main
tributary, Azhutha a part of which are located inside the boundary of PTR. The present paper provides an updated
checklist of the fish fauna of PTR including the Periyar Lake as well as
Periyar and Pamba rivers. The paper also
provides information on the distribution, relative abundance, threat status and
endemism of the various species encountered during the study.
Study Area
The study was undertaken in the
Periyar Tiger Reserve (9018’-9041’N & 76055’-77025’E;
Fig. 1), which covers an area of 777km2, of tropical evergreen,
semi- evergreen and moist deciduous forests. The elevation in PTR ranges from 800 to 2019 m with the highest point at
Vellimala. The Periyar Lake, which was
formed as a result of the construction of the Mullaperiyar Dam, has a total
area of 26km2 and a maximum depth of 46m at the highest water
level. Along with River Periyar, the
River Pamba and its main tributary, Azhutha also drain the Reserve. Ten locations, representing the different aquatic
habitats of the entire geographical area of PTR and located at least 5km apart
were selected for study. These included
Pamba (9025.2’N & 76058.2’E), Azhutha (9025’N
& 7704’E), Pachakkanam (9027.5’N & 7708.4’E),
Vallakkadavu (9036.3’N & 7704.6’E), Periyar Lake (9034.3’N
& 77010.4’E), Mullayar (9032’N & 77013’E),
Thannikkudy (9030’N & 77015.4’E), Ummikuppanthodu (9028.4’N
& 77014.5’E), Mlappara (9028.6’N & 77016.7’E)
and Moolavaigae (9021.4’N & 77016.3’E).
Fish Sampling
Sampling
was carried out in the selected locations of PTR in three seasons (pre monsoon
from February to May, monsoon from June to September and post monsoon from
October to January) for a period of two years (May 2004-August 2006). Fishing was carried out, using a variety of
gears including cast nets (16mm, 18mm, 22mm), gill nets (32mm, 38mm, 64mm,
78mm, 110mm), drag net (4mm), scoop nets and other local contrivances. Visual observations were also carried out if
the water was clear, to understand the distribution of fish species. Uniformity in catch per unit effort
(number/hour) was maintained in sampling following Bhat (2003) from which the
relative abundance of different species were assigned as very common, common,
moderately found, rare and very rare (Thomas et al. 2002). Under the same sampling effort we classify records of
5 or less than 5 individuals of a species as ‘very rare’, 5-20 as ‘rare’, 20-50
as ‘moderate’, 50-100 as ‘common’ and more than 100 as ‘very common’. This classification is not based on any
standard methodology or literature.
Fishes were identified following Day (1878), Talwar & Jhingran (1991) and Jayaram (1981, 1999). The threat status of each species was assigned following Dahanukar et al. (2004). The endemism of fish species was determined following Gopalakrishnan & Ponniah (2000), Gopi (2000) and Shaji et al. (2000).
Fish fauna and distribution
A total of 54 fish species
belonging to six orders and 19 families were recorded from various study
sites. The list of fish species and
details of their threat status, relative abundance, endemism and distribution at
different sampling sites are given in Table 1. The family Cyprinidae dominated with a numerical strength of 23 species
(43%), followed by Balitoridae with eight (15%) species. Four exotic species, viz. Oreochromis
mossambicus, Cyprinus
carpio carpio, Poecilia
reticulata andClarias gariepinus were also recorded.
Puntius fasciatus and Devario aequipinnatus were found distributed in nine
study sites. Six species, viz. Hypselobarbus kurali, Tor khudree, Rasbora daniconius, Puntius filamentosus, Garra mullya and Barilius gatensis were found in 5-8 locations. Fourty-six species were observed in less than
four locations of which 18 species were encountered only from single locations
each. The highest number of fish species
were encountered in Azhutha (30, 56%), followed by Pamba (23, 43%), and Periyar
Lake (20, 54%).
Threat status and relative abundance
Twenty-four species (45%) found in
PTR were listed as threatened. Lepidopygopsis typus has been listed as Critically
Endangered while 13 other species were Endangered and 10 were Vulnerable in
their threat status (Fig. 2). Nine (17%)
species were found to be very common, 10 (19%) species were common, 17 (31%)
species were moderately found, 12 (22%) species were rare and 6 (11%) species
were very rare in their relative abundance. Species such as Lepidopygopsis typus, Crossocheilus periyarensis, Travancoria jonesi, Nemacheilus periyarensis, Hypselobarbus periyarensis and Puntius denisonii were found to be ‘very rare’
inside the PTR.
Endemism
Twenty-two (41%) species were found
to be endemic to the Western Ghats of which six species were strictly endemic
to the Periyar Tiger Reserve. These
included four species of cyprinids, viz. Hypselobarbus periyarensis, Lepidopygopsis typus, Crossocheilus periyarensis and Garra periyarensis and two species of Balitorids Nemacheilus periyarensis and N. menoni. Figure 3 shows nature of endemism of fish species encountered in the
PTR.
DISCUSSION
The present study revealed that the
Periyar Lake and the river stream within the PTR harbour rich and diverse fish
fauna. Seventeen fish species were found
to be new additions to the PTR. This was
attributed to the fact that, the field surveys were carried out in the Periyar
Lake and its associated streams as well as Pamba River and its main tributary –
Azhutha. Nevertheless, the present study
also revealed the disappearance of some fish species in recent years from the
lake-stream system. Of the 35 fish
species reported by Chacko (1948) in Periyar Lake and connected streams,
cyprinids such as Puntius melanostigma (currently valid as P. mahecola), P. arulius, P. pinnauratus (P. sarana), Barilius bendelisis and Garra lampta; catfish species, Mystus vittatus and the feather back Nototpterus notopterus could not be collected during the
present study. Arun (1998) also had a
similar observation of not recording 16 species from the list of Chacko
(1948). Zacharias et al. (1996) reported 35 fish species
representing 11 families and 21 genera, of which Nemacheilus botia (Acanthocobitis botia), N. evezardi (Indoreonectes evezardi), Barilus bendelisis and Garra gotyla stenorhynchus were not represented in our
study. Garra mcclellandi, which was reported from Periyar
Lake and streams (Easa & Shaji 1997), was also not encountered in the
present study while, G. periyarensis which shows great similarity in
body morpho-meristics with G. mcclellandi was collected in adequate numbers. The present collection included all the 27
fishes recorded by Arun (1998) from the Periyar Lake and stream systems.
Majority (45%) of the fish fauna of
PTR is threatened. Ten species of
Cyprinids are threatened of which Lepidopygopsis typus is listed as Critically Endangered
and another five species categorised as Endangered. Among other families, four out of eight
balitorids and nine out of 21 species in all other families are
threatened. The high rate of endemism of
fish fauna in PTR, one of the richest biodiversity areas in Western Ghats is evident
from the present study. Restricted
distribution of fishes in PTR was also mentioned by Zacharias et al. (1996) and
Arun (1999) who reported 13 (37%) and 14 (52%) species of their fish collection
from PTR as endemic to Western Ghats. Large number of threatened fishes coupled with high rate of endemism
emphasizes the importance of this bio-reserve with respect to fish fauna and
points at the necessity of stringent protection measures for conserving its
unique fish germplasm.
Thirty-six (67%) fish species were
found restricted to Periyar lake-stream systems of which Lepidocephalus thermalis and all the four exotic fishes
were found only in Periyar Lake. Ten
species, viz., Lepidopygopsis typus, Puntius ophicephalus, Crossocheilus periyarensis, Hypselobarbus periyarensis, Garra periyarensis, Bhavania australis, Travancoria jonesi, Nemacheilus menoni, N. keralensis and Schistuara denisoni were observed only from upstream
locations of Periyar River such as Thannikkudy, Ummikuppanthodu, Mlappara and
Moolavaigae. Except Bhavania australis, all these species were low in
abundance (rare/very rare) and except Garra periyarensis, all the species of this group
were listed as threatened. Of the
different species found restricted to Pamba and Azhutha streams, eight species,
including endangered and rare Puntius denisonii and Garra surendranathanii, were found only in Azhutha
Stream. Fifteen species (28%) were found
distributed both in Periyar and Pamba river-stream systems which included Tor khudree, Puntius fasciatus, Ompok bimaculatus and Parambassis dayi. Besides high diversity, Azhutha also had the highest number (14) of
threatened fish species observed in any location, followed by Pamba (11) and
Mlappara (10). The highest number of low
abundant species was observed in Mlappara (7). Azhutha and Thannkkudy had five fish species each and Periyar Lake had
four species under low abundant category. The locations with highest number of threatened and low abundant fishes
deserve more attention for conservation and so may be prioritised as aquatic
sanctuaries or special protection zones in the management plans for conserving
fish diversity of PTR.
CONCLUSION
The present study illustrates the
status of PTR, as one of the richest areas of fish diversity and endemism
within the Western Ghats Hotspot. The
presence of a number of endemic and threatened fish species necessitates proper
conservation and management actions to be developed and implemented in PTR.
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