On the occurrence of the Fishing Cat Prionailurusviverrinus Bennet, 1833 (Carnivora:Felidae) in coastal Kerala, India
Ranjini Janardhanan 1, ShomitaMukherjee 2, P.V. Karunakaran 3& Ramana Athreya 4
1,2,3 Sálim Ali Centre for Ornithology and Natural History (SACON), Anaikatty Post, Coimbatore, Tamil Nadu 641108, India
4 Indian Institute of Science Education and
Research (IISER), 900, NCL Innovation Park, Dr Homi Bhabha Road, Pune, Maharashtra 411008, India
1 jranjini@gmail.com, 2shomitam@gmail.com (corresponding author), 3 karunakaran.pv@gmail.com,4 rathreya@iiserpune.ac.in
Abstract: The Fishing Cat Prionailurus viverrinus is classified as Endangered in the
IUCN Red List and yet its distribution range within India is not resolved. In spite of its potential habitat being
present in coastal Kerala, there are only a few, unsubstantiated records of the
cat. Moreover, its occurrence in
Sri Lanka strengthens the possibility of its presence (historical or current population)
in southern India, including Kerala. This survey was conducted to assess the occurrence of the Fishing Cat in
coastal Kerala through personal informal interviews with local people and
molecular analysis of scats. The
study failed to find any evidence of the occurrence of Fishing Cat in the
coastal areas of Kerala. We discuss
two possibilities - one, of the species existing earlier but driven to
extinction in recent decades, due to high levels of land conversion through
anthropogenic activities in these areas and the other of the Fishing Cat having
never occurred in coastal Kerala. A
speculative reasoning for its absence from the region could be related to the
difference in salinity levels between the eastern and western coasts of India which has already been documented. Moreover, fewer freshwater sources merge
into the sea in coastal areas of Kerala as compared to the eastern coast of
India. This could limit the
distribution of the Fishing Cat. The argument was also supported by the lack of any authentic report till
date or of local names for the Fishing Cat in the region.
Keywords: Coastal Kerala, distribution, Fishing Cat, scat
analysis.
Abbreviations: DNA - Deoxyribonucleic Acid; GADM - Global
Administrative areas; IUCN - International Union for the Conservation of
Nature; PCR - Polymerase Chain Reaction
doi: http://dx.doi.org/10.11609/JoTT.o3780.5569-73 | ZooBank: urn:lsid:zoobank.org:pub:5235A640-A54E-49C0-B754-8212EDDFA331
Editor: P.O.Nameer, Kerala Agricultural University, Thrissur, India Dateof publication: 26 March 2014 (online & print)
Manuscript details: Ms #
o3780 | Received 28 September 2013 | Final received 14 March 2014 | Finally
accepted 15 March 2014
Citation: Janardhanan, R., S.
Mukherjee, P.V. Karunakaran & R. Athreya (2014). On the occurrence of the Fishing Cat Prionailurus viverrinus Bennet, 1833 (Carnivora: Felidae) in coastal Kerala, India. Journal
of Threatened Taxa 6(3): 5569–5573; http://dx.doi.org/10.11609/JoTT.o3780.5569-73
Copyright: © Janardhanan et al. 2014. Creative Commons Attribution 3.0 UnportedLicense. JoTT allows unrestricted use of this
article in any medium, reproduction and distribution by providing adequate
credit to the authors and the source of publication.
Funding: The project was funded by Panthera Corporation, New York for field
work and The Indian
Institute for Science Education and Research
(IISER), Pune for laboratory space, equipment and chemicals.
Competing Interest: The
authors declare no competing interests.
Acknowledgements: This study emanates from a larger study supported by Panthera Corporation, New York. We thank Director, SACON for
facilitating and supporting the work. We thank IISER, Pune for laboratory space
and chemicals, the Forests and wildlife Department of Kerala for permits,
logistic help and discussions; Mahatma Gandhi University, School of
Environmental Sciences, Kottayam and IISER,
Trivandrum for accommodation in their guest houses. We thank M. Ravi, our driver during the
field survey. Several people we
interacted with, provided information on locations of sites, especially Ajay, Ayyapan, Chacko, Charan, Christopher, Prasanth, Rajeevan, Subramany and Toms for
providing information and accompanying us to various sites. We also thank Ginson,Subin and Thangappan for information
on the wild cats they had seen. We
are grateful to Hema for facilitating accommodation
at Trivandrum. We thank Mansi, Gouri and many others in
the laboratory at IISER, Pune for helping us through stressful troubleshooting
as well as making our stay and work enjoyable. We are grateful to Velumaniand Prachi who helped enormously with troubleshooting
as well as with ordering and suggesting various DNA extraction kits when we
needed them urgently. We thank the
editor and reviewers of the manuscript for their comments.
For
figures, images, tables -- click here
This study was undertaken to evaluate
unauthenticated records of the presence of the Fishing Cat Prionailurus viverrinus (Bennett, 1833) along coastal
Kerala, which could help establish the link to its distribution in Sri
Lanka. Owing to the severity of
threats to its habitat and its depleting population, the Fishing Cat is
included in Schedule I of the Indian Wildlife (Protection) Act (Anonymous 1972)
and listed as Endangered in the 2010 assessment of the IUCN Red List of Threatened
Species (Mukherjee et al. 2010a). This medium-sized cat is one among the 15 species of cats in India (Nowell & Jackson 1996), and weighs 6–16 kg (Sunquist & Sunquist2002). Wetlands such as mangroves,
rivers, ponds and canals are potential habitats for this cat.
The Fishing Cat is discontinuously
distributed in Asia and occurs in India, Pakistan (Sindh), Nepal, Bangladesh,
Sri Lanka, Thailand, Cambodia and Java (Pocock 1939;
Cutter 2009; Cutter & Cutter 2009). India and Sri Lanka are strongholds for the Fishing Cat. There is no authentic report from
peninsular Malaysia and its distribution in Laos and Sumatra is disputed
(Duckworth et al. 1999, 2009). Within India, the Fishing Cat is primarily distributed in the eastern
parts (West Bengal, Assam, Orissa, parts of Andhra Pradesh) and along the
foothills of the Himalaya in the Terai tract (Pocock 1939; Sunquist & Sunquist 2002). There are records from Keoladeo Ghana National
Park, Bharatpur (Nowell& Jackson 1996; Sunquist & Sunquist 2002; Mukherjee et al. 2012) and one recent camera
trap record from Ranthambhore Tiger Reserve (Sadhu
& Reddy 2013). Since the
distribution of this cat continues into Sri Lanka, it is expected to occur in
southern India. Despite the
presence of wetlands and mangroves along the western coast, the occurrence of
the Fishing Cat in this region is contentious (Prater1971; Sunquist & Sunquist2002; Menon 2003). Some authors have speculated a recent
extirpation of the species from this region due to habitat loss (Karanth 1986; Nowell &
Jackson 1996; Sunquist & Sunquist2002; Kumara & Singh 2007). On
the other hand, there are recent, though unsubstantiated, reports of the
Fishing Cat from Kannur, Kumarakom Mangroves and Periyar Tiger Reserve in Kerala (http://wild-cat.org/viverrinus/fishing-cat/index.htm?pv-distribution.htm, accessed on 20th August
2013; http://www.periyartigerreserve.org/check_list/mammals.pdf, accessed on 14thMarch 2014). Pocock(1939) questions the validity of the Malabar Coast (which in the 1930s would
include almost the entire western coast of India) as the locality of the type
specimen of the species. He remarks
that this could be an assumption since the donor submitted a specimen of a langur from the Western Ghats along with the Fishing Cat
specimen, though notes on the specimen mention the locality as just
‘India’. The record from Periyar Tiger Reserve too is not substantiated with
photographic or genetic evidence and so remains speculative.
One scenario suggests that the species was
present in this region historically and at present occurs in small populations,
in danger of extinction, or has already been extirpated from this region. Alternatively, the possibility of the
cat having never occurred here also cannot be rejected. Solving this is important, not just to
enable conservation of this Endangered (Mukherjee et al. 2010a) cat but also to
trace its historical dispersal into Sri Lanka.
Given the background, the present survey
was undertaken to evaluate Fishing Cat distribution in this region. We surveyed potential habitats in
coastal Kerala for Fishing Cat through scat collection and assignment of scats
to species using molecular tools. We also interviewed local inhabitants for information on the Fishing Cat
and its potential habitat in the locality.
Method: The
survey localities were initially selected based on the presence of relatively
intact mangrove patches and earlier unauthenticated records of the
species. The survey lasted for a
week (20–27 January 2013) and several localities under five districts
were visited (Table 1, Fig. 1). Upon reaching a locality, we contacted naturalists, research institutes
and forest department personnel who could provide us with information on
possible records of the cat or of potential habitats (wetlands, mangroves and
marshy areas). We also interacted
with people in the locality for any information on small cats in the area. A few people whom we interviewed claimed
to have seen ‘wild’ cats and they were asked to describe the cat through its
tail length (e.g., was the tail long or short?), body size (would the size
compare with house cat or dog?), height of the cat, length of legs, coat
pattern and any other behaviour if observed.
Scat collection and analysis: Based on
information obtained on habitats, we visited specific localities for sample
collection. We followed existing paths to survey an area. All scats encountered were collected
since visual assignment to predators is difficult given that several small
carnivores coexist in an area. Scats were collected in separate vials. Special care was taken while collecting,
to avoid contact with bare hands in order to prevent contamination across
scats. Very old and degraded (disintegrated
and without the smooth outer coating) scats were not collected.
Scats samples were carried to the
laboratory where alcohol was added to preserve DNA for further analysis. Faecal
DNA was extracted using commercially available extraction kits from QIAGEN (QIAAmp) and scats were assigned to the predator species by
using the felid specific primer for the 16s rRNAregion and a restriction digestion with Hae III, Ase I and Dpn I, following
Mukherjee et al. (2010b).
Results: We
visited five districts, Kannur, Kozhikode, Kottayam, Alleppey and Kollam (Table 1). All localities visited were severely
disturbed with higher levels of disturbance in southern Kerala.
The local people interviewed in places we
visited could not provide any information on Fishing Cat presence. Moreover, there was no local name for
the species. The descriptions by locals of cats they had sighted matched either
the Jungle Cat or Rusty-spotted Cat (Image 3). There was one past unconfirmed record of
a Fishing Cat in the 1990s that was rescued from a well near Parassinikadavu Snake Park in Kannur District. The cat was held in captivity at the
Snake Park until it died in 1993. Subsequently, the skin of the cat was kept at the Snake Park until a
fire left no trace of it. There are
no further details available nor is there any
photographic evidence and the record remains unauthenticated. We also contacted
the person (P.C. Rajeevan) who claimed to have seen a
Fishing Cat near Parassinikadavu temple, Kannur in
2009 (http://wild-cat.org/viverrinus/fishing-cat/index.htm?pv-distribution.htm,
accessed on 20 August
2013). He told us that he assumed
it was a Fishing Cat as he saw it swimming across the river. The record by Jafer Palot(http://wild-cat.org/viverrinus/fishing-cat/index.htm?pv-distribution.htm.,
accessed on 20 August 2013) is not supplemented with photographic evidence.
Scat analysis: We collected 51 scats from
all the sites visited (Image 1). Of
these, 14 were positive for felids. Restriction digestions were carried out on
10 scats. Four scats had
insufficient predator DNA after amplification with felid primers and were not
included in the restriction digestions. We could identify six jungle cats and two house cats from the
restriction digestion profiles (Image 2). Restriction profiles of PCR products
from two scats did not give clear results and were classified as unknown. No
scat was assigned to Fishing Cat.
Discussion: Our
survey for Fishing Cat in the coastal areas of Kerala did not suggest the
current existence of a population in the region. Interviews with people in the survey
sites, observations on the habitat and assignment of scats to predators using
molecular tools failed to provide any authentic indication of its presence.
The local people were familiar with other
cats present in the region such as the Jungle Cat, Leopard Cat and
Rusty-spotted Cat and could describe them well. They even have local names for these
cats. However, there seemed to be
no local name for the Fishing Cat unlike in other areas of the country where
Fishing Cats are seen (Tiasa Adhya pers. comm.
2013). The cat is fairly large and
at 6-16 kg body mass (Sunquist & Sunquist 2002), is much larger than the Jungle Cat (average
body mass 5kg), Leopard Cat (average body mass 3kg) and Rusty Spotted Cat
(average body mass <2kg) (Pocock 1939; Sunquist & Sunquist2002). If it did occur along human
dominated coastal Kerala, it would perhaps not go unnoticed, given its
size. Additionally, during scat
collection we did not come across any site that had large depositions of scat,
behaviour peculiar to the Fishing Cat seen across its distribution range in
India (Mukherjee et al. 2012).
The results were surprising as coastal
areas in Kerala are rich in water bodies, mangroves and marshes that are
similar to the habitat of the Fishing Cat elsewhere. From our results we cannot conclude if
Fishing Cats have only relatively recently been extirpated from this region or
had never occurred along coastal Kerala.
We met Mr P.C. Rajeevan,
one of the two people who claim to have seen the Fishing Cat in Kannur District
in 2009. He clarified that he
assumed it was a Fishing Cat because it was swimming across the Ramapuram River. Dr. Jafer Palot was the other person who claims to have seen the cat
twice in Kannur, one was the captive individual in the ParassinikadavuSnake Park sometime in the early 1990s, of which there is no photographic or
genetic evidence and the other sighting was of an adult at the Chemballikundu mangroves in 1995. He based this identification on the
individual he saw at the Snake Park. Since both records are unsubstantiated it is prudent to treat them with
caution owing to the several instances of misidentification of Leopard Cats and
house cats as Fishing Cats, even by experts (Duckworth et al. 2009, Shomita Mukherjee pers. obs. 2009, 2010, 2014). Furthermore, the state of the mangroves
is believed to have improved since the formation of the Kerala Coastal Zone
Management Authority in 1998 (http://www.envfor.nic.in/legis/crz/1001.html,
accessed on 21st August 2013). Despite
this, in our current survey we found the mangroves to be in a devastated
condition. Hence, it is reasonable
to accept that in the 1990s when these sightings were made, the habitat was in
a worse state. From our present
observations we reason that it would not be feasible for the Fishing Cat to
survive in such small fragments of highly polluted mangroves.
One possibility could be that the species
was present here earlier and could have recently been extirpated as suggested
by Karanth (1986) and Kumara & Singh (2007). Our observations on the present state of
potential habitat of the species reveal alarming levels of disturbance due to
anthropogenic activities. These
habitats are either completely destroyed for civil constructions, or have
undergone severe land conversion. Many mangrove patches have been converted to coconut grooves, paddy
fields or aquaculture farms. Some
aquaculture farms are abandoned but retain water in them. The wetlands, canals, marshes and
mangroves that we visited were all deeply fragmented into small patches of less
than 1km2 area and polluted with waste from neighbouring urban
sprawls (Images 4 & 5). With
such severe disturbance and fragmentation it is unlikely that the Fishing Cat
could currently survive in these patches. Moreover, the backwater canals seem to be devoid of any large fish that
could sustain a population of a medium-sized felid. However, in eastern and northern India
the Fishing Cat occurs around human habitations (Mukherjee et al. 2012). Furthermore, in rural West Bengal,
locals farm large fish in their home ponds and this perhaps aids the
persistence of the Fishing Cat. Another threat for all small wild felids that we perceived during this
study was that local people were not receptive to the presence of small cats as
they predate on their poultry. An
example is a case from Alleppey where a female Rusty
Spotted Cat was trapped and killed, and its litter though adopted by local
people, did not survive.
The second argument would be that the
species never occurred in this region. This is puzzling especially since their dispersal into Sri Lanka could
only have occurred through southern India. It is possible that this happened through southeasternIndia (Andhra Pradesh/Tamil Nadu).
We hypothesize that the higher salinity
levels along the western coast as compared to the eastern coast (Shankar & Shetye 2001) could be a factor preventing Fishing Cats from
colonising the western coast of India. Further, the extent of area under wetlands is higher along the eastern
coast as compared to the western coast of India. A reason for lower salinity in the
eastern coast is also partly due to a larger area under river-fed wetlands when
compared with the western coast (Selvam 2003). Though conjectural, salinity being the
limiting factor for Fishing Cat distribution along the western coast of India
can be tested through niche models. Yet there is a possibility of Fishing Cat
presence in inland areas with fresh water sources especially along the Western
Ghats and the absence of records from this region is confusing.
We conclude that given our observations on
the condition of the wetlands, water bodies, mangroves and canals along coastal
Kerala and discussions with locals, it is unlikely that the Fishing Cat
currently occurs in the region. This was supported by results from the scat sampling done in this
region. We also hypothesise that
the Fishing Cat perhaps never occurred along the western coast of India due to
higher salinity levels as compared to the eastern coast. However, this needs to be tested through
further analysis using niche models.
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