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The Western Ghats region of India is an area of exceptional freshwater biodiversity and endemism. Mahseer of the genus Tor are considered prized sport fishes of great cultural significance; nevertheless, they are threatened as a result of increasing anthropogenic stressors. In the River Cauvery, the mahseer community comprises a 'blue-finned' and an orange-finned, 'hump-backed' fish. Whilst it is not yet known whether these are distinct species or 2 different phenotypes, evidence suggests that the hump-backed phenotype is endemic to the river, whereas the blue-finned phenotype was introduced in the 1980s. Angler-catch data from a managed fishery on the River Cauvery, gathered between 1998 and 2012 and comprising 23 620 h of fishing effort, revealed that captured individuals ranged in size from 0.45 to 46.8 kg, with the blue-finned phenotype comprising 95% of all captured fish and the remainder being hump-backed. The catch per unit effort (CPUE) of the blue-finned phenotype significantly increased over the study period, while the mean weight of individual fish significantly declined. By contrast, the CPUE of the hump-backed phenotype declined significantly over the period, with individual mean weights significantly increasing. These data suggest a recent recruitment collapse in the hump-backed phenotype resulting in an ageing population that may be headed towards extinction. The introduced blue-finned phenotype, however, continues to recruit strongly, suggesting that the mahseer community of the River Cauvery has undergone considerable shifts in the last 30 yr.
Endang Species Res
Vol. 28: 11–17, 2015
doi: 10.3354/esr00673 Published online May 13
Freshwater ecosystems and their biodiversity re -
main among the most endangered and poorly pro-
tected resources on Earth (Millennium Ecosystem
Assessment 2005, Dudgeon 2011, Cooke et al. 2012),
with almost 1 in 3 freshwater species facing a high
risk of extinction (Collen et al. 2014). Of the 5785 spe-
cies of freshwater fish assessed for their conservation
status by the IUCN, more than 36% are threatened,
and over 60 species have gone extinct since 1500
(Carrizo et al. 2013).
The Western Ghats region of India, part of the
Western Ghats-Sri Lanka Biodiversity Hotspot, is
an area of exceptional freshwater biodiversity and
en demism (Dahanukar et al. 2011, Raghavan et al.
2015). Nevertheless, approximately half of the
region’s endemic fish species are threatened with
© The authors 2015. Open Access under Creative Commons by
Attribution Licence. Use, distribution and reproduction are un -
restricted. Authors and original publication must be credited.
Publisher: Inter-Research ·
*Corresponding author:
The legendary hump-backed mahseer Tor sp. of
India’s River Cauvery: an endemic fish swimming
towards extinction?
Adrian C. Pinder1,2,*, Rajeev Raghavan1,3, 4, J. Robert Britton2
1Mahseer Trust, c/o The Freshwater Biological Association, East Stoke River Laboratory, Wareham, Dorset BH20 6BB, UK
2Faculty of Science and Technology, Bournemouth University, Fern Barrow, Poole, Dorset BH12 5BB, UK
3Conservation Research Group (CRG), St Albert’s College, Kochi, Kerala, 682 018, Kerala, India
4Laboratory of Systematics, Ecology and Conservation, Zoo Outreach Organization (ZOO), Coimbatore, 641 035, Tamil Nadu, India
ABSTRACT: The Western Ghats region of India is an area of exceptional freshwater biodiversity
and endemism. Mahseer of the genus Tor are considered prized sport fishes of great cultural sig-
nificance; nevertheless, they are threatened as a result of increasing anthropogenic stressors. In
the River Cauvery, the mahseer community comprises a ‘blue-finned’ and an orange-finned,
‘hump-backed’ fish. Whilst it is not yet known whether these are distinct species or 2 different
phenotypes, evidence suggests that the hump-backed phenotype is endemic to the river, whereas
the blue-finned phenotype was introduced in the 1980s. Angler-catch data from a managed fish-
ery on the River Cauvery, gathered between 1998 and 2012 and comprising 23 620 h of fishing
effort, revealed that captured individuals ranged in size from 0.45 to 46.8 kg, with the blue-finned
phenotype comprising 95% of all captured fish and the remainder being hump-backed. The catch
per unit effort (CPUE) of the blue-finned phenotype significantly increased over the study period,
while the mean weight of individual fish significantly declined. By contrast, the CPUE of the
hump-backed phenotype declined significantly over the period, with individual mean weights
significantly increasing. These data suggest a recent recruitment collapse in the hump-backed
phenotype resulting in an ageing population that may be headed towards extinction. The intro-
duced blue-finned phenotype, however, continues to recruit strongly, suggesting that the mahseer
community of the River Cauvery has undergone considerable shifts in the last 30 yr.
KEY WORDS: Western Ghats · Tor khudree · Tor mussullah · Catch and release · Endemic ·
Recruitment · Recreational fisheries
Endang Species Res 28: 11–17, 2015
extinction (Dahanukar et al. 2011), a result of esca-
lating anthropogenic pressures and threats, lack of
governmental support for freshwater fish conserva-
tion, jurisdictional issues and oversights, poor en -
forcement of existing laws and implementation of
top-down approaches (Dahanukar et al. 2011, Rag-
havan et al. 2011, 2013, Pinder & Raghavan 2013).
In the region, no freshwater fish has received as
much attention from the public as the mahseer (Tor
spp.), a group of large-bodied fishes of the Cypri -
nidae family. These species are represented in the
ancient Indian literature (Nautiyal 2014), are
revered as gods (Dandekar 2011) and have been
globally recognised as premier game fishes since
colonial times (Thomas 1873, Dhu 1923, MacDonald
1948). They are, however, among the most threat-
ened groups of freshwater fish in the Western
Ghats, impacted by habitat loss and destructive
fishing, yet there are many gaps in our knowledge
of their taxonomy, natural histories and population
statuses (Pinder & Raghavan 2013). Of particular
concern are their systematics and taxonomy, with
continuing ambiguity about the identity and distri-
bution of species. The increasing volume of infor-
mation in the peer-reviewed literature has also
been relatively unhelpful to date as it often pro-
vides contrasting perspectives on these subjects (cf.
Knight et al. 2013, Khare et al. 2014).
In British colonial times, the mahseer of the River
Cauvery in the Western Ghats were premier sport
fishes, but interest in their fishery diminished follow-
ing Indian independence in 1947, leading many to
assume the fish had become extinct. In 1978, how-
ever, a small team of British explorers were success-
ful in catching mahseer weighing up to 42 kg (TWFT
1984), reigniting global interest in the river as a pre-
mier freshwater sport fishing destination and launch-
ing a new era of Indian angling ecotourism (Everard
& Kataria 2011). The fishery was developed on strict
catch-and-release (C&R) principles that realised tan-
gible river conservation and societal benefits (Pinder
& Raghavan 2013). Despite these benefits, govern-
mental reinterpretation of the Indian Wildlife Protec-
tion Act of 1972 resulted in a shutdown of the angling
camps from 2012, exposing aquatic biodiversity gen-
erally and mahseer specifically to elevated levels of
illegal and destructive levels of exploitation (e.g.
dynamite fishing) in the river.
A recent study on the mahseer fishery of the River
Cauvery highlighted the value of angler catch
returns in monitoring temporal population trends in
mahseer numbers and weight (Pinder et al. in press),
and highlighted a marked shift in the weight of indi-
vidual fish being captured despite a relatively consis-
tent methodology used across the time series, with
increasingly smaller fish being captured over time.
Although the study speculated that this related to a
change in the mahseer community structure from the
endemic hump-backed (orange-finned) phenotype
(that grows to over 50 kg) to a distinct blue-finned,
smaller phenotype, this was not tested. In the present
study we thus further examined the dataset of Pinder
et al. (in press), with the following objectives: (1) to
quantify any shift in mahseer community structure
and the current status of both phenotypes; (2) to
identify the vulnerability to extinction of the hump-
backed phenotype in the River Cauvery and the con-
servation implications of the presence of the blue-
finned phenotype; and (3) to present the urgency
associated with defining the true scientific identity of
the ‘hump-backed mahseer’ to advance the ecologi-
cal knowledge required to inform species-specific
conservation action. Note that whilst the 2 mahseer
phenotypes have previously been referenced respec-
tively as T. mussullah and T. khudree, their taxo-
nomic classifications are currently under scrutiny,
and to avoid perpetuating erroneous scientific
names, they are referred to here as only phenotypes,
i.e. as ‘hump-backed’ and ‘blue-finned’, respectively.
Note that the hump-backed phenotype has, histori-
cally, only been recorded from the River Cauvery
basin (Thomas 1873), including its tributaries, the
Kabini (TWFT 1984), Bhavani (Hora 1943) and the
Moyar (Jayaram 1997); and thus, based on its re -
stricted distribution alone, it may be considered as
highly vulnerable to extinction (Helfman 2007, Giam
et al. 2011). By contrast, the blue-finned phenotype
was not recorded in the river prior to 1993 and is
believed to have originated from artificially propa-
gated stock (Desai 2003).
The study area on the River Cauvery was the Gal-
ibore Fishing Camp, 1 of 4 former angling camps
situated on the River Cauvery encompassed by the
Cauvery Wildlife Sanctuary (an IUCN Category IV
Protected Area) in the state of Karnataka, part of
the Western Ghats in Southern India (Fig. 1).
Between mid-January and mid-March of 1998 to
2012, the Galibore fishery was subject to regulated
angling pressure (maximum 10 rods d−1), practising
a very strict C&R policy. Structured catch data col-
lected during this period included daily records of
individual angler identity (name); hours fished
Pinder et al.: Endemic mahseer swimming towards extinction
(effort); number of fish caught; weight of individual
fish (the standard metric used by anglers was impe-
rial pounds [lbs], where 1 lb = 0.45 kg); and notes
relating to mahseer phenotype (denoted as hump-
backed, H; and blue-finned, B). With the exception
of 2 years (1999 and 2000), a sub-sample of catch
returns spanning 1998 to 2012 were available from
the fishery manager and complemented by addi-
tional returns retained by anglers over the same
period. A summary of the data for each year is pre-
sented in Table 1.
While all larger mahseer (>10 lbs
[>4.5 kg]) were typically weighed to the
nearest pound using spring-loaded
weighing scales, many weights for
smaller in dividual fish were found to be
restricted to estimates. Furthermore,
where an angler recorded a large num-
ber of fish during a single (4 h) fishing
session, records were typically limited to
the weight of the largest fish, with the re -
maining catch enumerated, e.g. ‘6 fish to
18 lbs’. Following consultation with the
camp manager and a selection of the
anglers, and as per Pinder et al. (in
press), these data were standardised by
recording 1 fish at 18 lbs with all other
individuals recorded as weighing 5 lbs
(with 5 lbs [2.25 kg] representing the
threshold at which most anglers were
considered to neither weigh nor estimate
the weight of their fish). Where the
weight of the largest individual did not
exceed 5 lbs (either estimated or
weighed), e.g. ‘9 fish to 5 lbs’, data were standard-
ised by applying a 50% weight reduction to the re -
maining 8 fish for which weights were not recorded.
In this example, the adjusted record would account
for 1 fish of 5 lbs and 8 fish of 2.5 lbs. While we
acknowledge the inherent limitations of these stan-
dardised data, the allocation of arbitrary weights (as
guided by the local angling community) has facili-
tated a valuable measure of the numbers of young
fish recruiting to the population over the course of
the study period.
Catch returns were initially sorted into the respec-
tive phenotypes and enumerated as annual totals. To
identify whether the number of blue-finned mahseer
captured each year was a good predictor of the num-
ber of hump-backed mahseer captured, their rela-
tionship was tested using linear regression. To assess
whether the differences in the number of each phe-
notype captured per year were significantly differ-
ent, the gradient of the regression line (b) was used
to test the null hypothesis that equal numbers of the
phenotypes were captured each year, with this
accepted when bwas not significantly different from
1.0 and vice versa, based on its 95% confidence lim-
its. The catch per unit effort (CPUE) of each pheno-
type was then determined for each year and
expressed as the number of each phenotype cap-
tured per hour per year. Differences in CPUE value
between the 2 phenotypes were tested using
ANOVA. The temporal pattern in the CPUE of each
Year Total no. Total hours No. of mahseer captured:
of anglers fished Hump-backed Blue-finned
1998 6 580 14 59
2001 9 820 38 153
2002 10 1080 6 81
2003 19 1920 80 148
2004 25 2640 95 342
2005 28 2604 25 407
2006 17 1608 6 228
2007 27 2632 3 452
2008 33 3188 5 1022
2009 11 1196 4 346
2010 29 1984 9 887
2011 35 2388 1 1095
2012 10 980 3 653
Table 1. Temporal resolution of data recovered to determine
catch per unit effort (CPUE) for mahseer. Individual angler
numbers yr−1 (1998−2012) and hours fished (effort) between
January and March in each year are given
Fig. 1. Location of the River Cauvery and the study area in the Western
Ghats of India. The solid line represents the 7 km Galibore fishery (G). The
dashed line represents the 22 km extent of the former catch and release
mahseer fishery; light grey lines show the course of the River Canvery and
its tributaries
Endang Species Res 28: 11–17, 2015
phenotype was tested for significance using linear
regression, where the independent variable was the
number of years since the study commenced and the
dependent variable was the annual CPUE of the
mahseer phenotype. To identify whether there was a
relationship between the temporal patterns in the
CPUE of the hump-backed mahseer and the CPUE of
the blue-finned mahseer, Pearson’s correlation coef-
ficient was used in cross-correlation, using time 0 (i.e.
testing of CPUE data from the same year) and at time
lags of −1 to −3 yr.
For the weight of individual fish, differences be -
tween phenotypes were tested using a Mann-Whit-
ney U-test because the data were not normally dis-
tributed. The temporal pattern in the mean weights
of each phenotype was then tested for significance
using linear regression, where the independent vari-
able was the number of years since the study com-
menced and the dependent variable was the mean
annual weight of the mahseer phenotype. This was
also repeated for all fish captured, i.e. by combining
data from both phenotypes.
Throughout the study, where error is expressed
around the mean, it denotes standard error.
Over the study period, 23 620 h of fishing effort
were applied to C&R of 6162 mahseer, ranging in size
from 1 to 104 lbs (0.45−46.8 kg) in weight. Of these
mahseer, 95% comprised the blue-finned phenotype,
with the remainder being hump-backed (Table 1).
The number of blue-finned and hump-backed mah-
seer captured per year were not significantly related
(R2= 0.14, F1,11 = 1.73, p > 0.05; Fig. 2a) and the slope
of this regression line (b) indicated that significantly
more blue-finned mahseer were captured per year
than hump-backed mahseer (95% confidence inter-
vals: −0.09 to 0.02; Fig. 2a). The annual CPUE of the
blue-finned phenotype was also significantly higher
than that of the hump-backed phenotype (ANOVA:
F1,22 = 21.78, p < 0.01), with the mean CPUE of the
blue-finned phenotype being 0.248 ± 0.050 ind. h−1
and that of the hump-backed phenotype being 0.014
± 0.005 ind. h−1 (Fig. 2b,c). Across the study period,
the CPUE of the blue-finned phenotype significantly
increased with time (Fig. 2b) (R2= 0.70, F1,11 = 25.65,
p < 0.01), whereas it significantly decreased in the
hump-backed phenotype (R2= 0.68, F1,11 = 9.54, p <
0.01; Fig. 2c). The cross-correlation revealed that the
relationship of the annual CPUE of the hump-backed
phenotype was not significantly correlated to the
CPUE of the blue-finned mahseer at time 0, −2 and
−3 yr (r = −0.49, −0.30 and −0.25, respectively, p >
0.05 in all cases), but was significant at time −1 yr
(−0.58, p < 0.05; Fig. 2b,c).
1998 2000 2002 2004 2006 2008 2010 2012
CPUE hump-backed mahseer
(ind. h–1)
CPUE blue-finned mahseer
(ind. h
0 200 400 600 800 1000 1200
No. of blue-finned mahseer captured yr–1
No. of hump-backed mahseer
captured yr
1998 2000 2002 2004 2006 2008 2010 2012
Fig. 2. (a) Comparison of the number of each mahseer pheno-
type captured per year (×), where the solid line represents the
fitted relationship (linear regression) and the dashed line repre-
sents the null hypothesis that equal numbers of each phenotype
were captured each year. Annual catch per unit effort (CPUE) of
(b) the blue-finned and (c) hump-backed mahseer across the
study period. Error bars are not displayed for reasons of clarity
Pinder et al.: Endemic mahseer swimming towards extinction
Across the study period, the mean weight of the
hump-backed mahseer was 24.3 ± 1.5 lbs (range:
1−104 lbs [0.45−46.8 kg]) and that of the blue-finned
was 7.8 ± 0.1 lbs (range: 1−62 lbs [0.45−27.9 kg]); this
difference was significant (Mann-Whitney U-test: Z=
−14.37, p < 0.01; Fig. 3). For the hump-backed pheno-
type, mean weights per year significantly in creased
over the study period (R2= 0.45, F1,11 = 8.82, p < 0.02),
ranging between 16 lbs (7.2 kg) in 2001 and 67.5 lbs
(30.4 kg) in 2011 (Fig. 3a). In contrast, the mean
weight of the blue-finned phenotype significantly
decreased over the study period (R2= 0.63, F1,11 =
18.60, p < 0.01), ranging between 13.8 lbs (6.2 kg) in
1998 and 5.4 lbs (2.4 kg) in 2012 (Fig. 3b). Indeed,
across the study period, 42% of the captured blue-
finned phenotype were below 5 lbs (<2.25 kg) in
weight. When the data for both phenotypes were
combined, the highest mean weight of captured fish
was recorded in 1998 (17.7 ± 2.0 lbs; 8.0 ± 0.9 kg) and
the lowest was in 2012 (5.6 ± 0.3 lbs; 2.5 ± 0.1 kg),
with a significant temporal decline in mean weight
also evident (R2= 0.83, F1,11 = 51.71, p < 0.01).
The angler catch data revealed some distinct pat-
terns in the composition of the mahseer catches over
time, with a significantly increasing catch rate of the
blue-finned phenotype and a significant decline in
catch rates of the hump-backed phenotype. Despite
considerable technological advances in recreational
fishing gears (e.g. development of braided lines), the
challenging environmental conditions and presence
of sharp submerged rocks in the River Cauvery has
dictated that angling techniques remained consistent
over the period and provided a representative catch
rate of all mahseer between 1 and 104 lbs (0.45
46.8 kg) (Pinder et al. in press). Hence, these outputs
indicate that the mahseer community of the river is
primarily currently comprised of the blue-finned
phenotype whose mean weight is substantially lower
than that of the hump-backed phenotype. The com-
bination of the significant decline in catch rate of the
hump-backed phenotype and the significant increase
in the sizes of individual fish captured suggests that
there has been a relatively recent issue with their
recruitment in the river, whereas this is not evident in
the blue-finned phenotype.
The recruitment collapse of the hump-backed phe-
notype does not appear to be associated with antago-
nistic interactions between the 2 phenotypes, given
the output of the cross-correlation. It does correspond
with anecdotal reports of the failure of the 2004 mon-
soon (i.e. very low rainfall), which dramatically re -
duced river discharge during the 2005 fishing season
and resulted in the observed mortality of several large
hump-backed mahseer (M. Brown pers. comm.). Their
overall decline was also coincident with an increase
in angling pressure, and although C&R was prac-
tised, it could be speculated that the capture and sub-
sequent handling of some of the large hump-backed
individuals resulted in their post-release mortality
and thus loss from the spawning stock; however,
there is no supporting anecdotal evidence of this.
Irrespective of this, without action to remediate or
mitigate this population decline and recruitment col-
lapse in the hump-backed phenotype, their popula-
Weight (lb)
Fig. 3. Weight of individual mahseer captured per year
for (a) hump-backed and (b) blue-finned. Filled circles
represent mean annual weight, horizontal lines represent
the 25th, 50th and 75th percentiles, and the error bars
represent the 10th and 90th percentiles. 1 lb = 0.45 kg
Endang Species Res 28: 11–17, 2015
tion in the River Cauvery appears to be increasingly
unsustainable and heading towards extinction.
Historical information, including photographs, is
critical to understand the status of species and popu-
lations (see McClenachan 2009, McClenachan et al.
2012) and reveals that only the hump-backed pheno-
type was captured and photographed during colonial
times. Indeed, photographs of the hump-backed phe-
notype, as typified by its golden body and orange
fins, are distributed throughout the angling literature
and all depict individuals captured in the Cauvery
river system, suggesting the absence of this pheno-
type in other rivers (Thomas 1873, Dhu 1923, MacDo-
nald 1948, Shanmukha 1996). Moreover, until 1993,
it was the only mahseer phenotype captured by
anglers in the Cauvery, suggesting in all probability
that this phenotype is endemic. The appearance of
the blue-finned phenotype is likely to relate to fish
movements and hatchery-reared fish that were initi-
ated in the 1970s. In response to the realisation that a
combination of anthropogenic threats was causing a
rapid decline in mahseer stocks across India, the Tata
Electric Companies (TEC) fish-seed hatchery at Lon-
avla, Maharashtra, began the large-scale breeding
and culture of mahseer species (Tor khudree, T. tor,
T. putitora and the ambiguous ‘T. mussullah’) for
national distribution of fingerlings to augment stocks
(Shanmukha 1996, Sehgal 1999, Ogale 2002, Desai
2003). The dates and geographical details of where
brood-stock was acquired and the seed distribution
of the exact species are scarce, although activities
included the experimental hybridisation between
mahseer species (Ogale & Kulkarni 1987), and the
translocation of species beyond their endemic geo-
graphical ranges (including outside the country) has
been documented (Ogale 2002, Desai 2003). In 1978,
the Trans World Fishing Team (TWFT) visited the
TEC hatchery and provided the first record of blue-
finned mahseer, describing the culture of ‘a strik-
ingly blue-finned fish’, which was targeted for
release in the nearby rivers and reservoirs (TWFT
1984). Sehgal (1999) and Desai (2003) have since
reported the release of 150 000 advanced fry/finger-
lings of T. khudree to the River Cauvery by the
Department of Fisheries of the State of Karnataka,
with further documentation that stocking activity on
the Cauvery included 30 000 mahseer by the Fish
Farmers Development Agency, Mysore (Shanmukha
1996), 15 000 mahseer fingerlings to the Coorg
Wildlife Society and 10 000 to the Wildlife Associa-
tion of South India (Ogale 2002).
The dataset used in the present study reveals that
the blue-finned phenotype was sufficiently well
established in the River Cauvery by 1998 to enable
it to already be captured in greater numbers than
the hump-backed phenotype, with individual speci-
mens attaining weights up to 48 lbs (21.6 kg). Also,
whereas the catch data suggest declines in the
hump-backed phenotype associated with poor
recruitment due to the declining catch rate and
increasing individual fish size, data from the blue-
finned phenotype suggest that sufficient recruitment
occurred to enable large numbers of smaller fish to
be captured by anglers, as 42% of all blue-finned
mahseer captured in the study period were below
5 lbs (<2.25 kg) in weight. Due to the lack of detailed
catch data prior to 1998, records on the blue-finned
phenotype are limited to articles in the popular press
and media. The earliest record communicating their
presence was in 1993 during the mahseer world
angling championships when a fish of approximately
11 lbs (5 kg) was captured (A. Clark pers. comm.).
Based on current knowledge of the growth rates of
the blue-finned phenotype and the demographic
structure of the population by 1998 (see Pinder et al.
in press), it seems highly probable that the blue-
finned phenotype originated from the TEC hatchery
and was introduced during the late 1980s. Under-
standing the ecological mechanisms responsible for
the high population expansion of the blue-finned
phenotype at the expense of the hump-backed phe-
notype in recent years is currently constrained by
insufficient knowledge pertaining to the autecology
and genetics of both phenotypes. However, life his-
tory traits, such as growth, age at maturity and fecun-
dity are considered to be likely factors, with
increased plasticity in the successful utilisation of
key-function habitats (e.g. spawning, feeding) poten-
tially providing the blue-finned mahseer with greater
niche capacity to exploit and thus facilitating com-
petitive displacement. In addition, direct predation
and hybridisation have also been frequently cited as
factors increasing the threat to endemic fishes
through the introduction of new species (Crivelli
Since the Galibore fishery was closed in 2012, the
fish community has been reported to have been sub-
jected to elevated poaching pressure, but there are
currently no means of measuring and tracking com-
munity and population metrics against the baseline
data established from the current dataset. Accord-
ingly, there is an immediate urgency to establish the
status of the hump-backed mahseer throughout the
Cauvery basin and acquire genetic material to secure
the true taxonomic identity of this animal as a precur-
sor to exploring potential species survival planning.
Pinder et al.: Endemic mahseer swimming towards extinction
Acknowledgements. We thank Sportquest Holidays Ltd, D.
Plummer and M. Brown for the provision of catch records.
We are grateful to A. Clarke and M. Clarke of the Trans
World Fishing Team for historical insight into the fishery and
A. Kanagavel for assisting in the production of Fig. 1. This
research was supported by the Mahseer Trust.
Carrizo SF, Smith KG, Darwall WRT (2013) Progress to -
wards a global assessment of the status of freshwater fis-
hes (Pisces) for the IUCN Red List: application to conser-
vation programmes in zoos and aquariums. Int Zoo Yearb
Collen B, Whitton F, Dyer EE, Baillie JEM and others (2014)
Global patterns of freshwater species diversity, threat
and endemism. Glob Ecol Biogeogr 23:40−51
Cooke SJ, Paukert C, Hogan Z (2012) Endangered river fish:
factors hindering conservation and restoration. Endang
Species Res 17:179−191
Crivelli AJ (1995) Are fish introductions a threat to endemic
freshwater fishes in the northern Mediterranean region?
Biol Conserv 72:311−319
Dahanukar N, Raghavan R, Ali A, Abraham R, Shaji CP (2011)
The status and distribution of freshwater fishes of the
Western Ghats. In: Molur S, Smith KG, Daniel BA, Darwall
WRT (comps.) The status and distribution of freshwater
biodiversity in the Western Ghats, India. IUCN Cambridge
and Zoo Outreach Organization, Coimbatore, p 21–48
Dandekar P (2011) India’s community fish sanctuaries pro-
tect wild fish and rivers. World River Rev 26:1−7
Desai VR (2003) Synopsis of biological data on the tor mah-
seer Tor tor (Hamilton, 1822). FAO Fisheries Synopsis
No. 158. FAO, Rome
Dhu S (1923) The angler in India or the mighty mahseer.
Natraj Publishers, Dehra Dun
Dudgeon D (2011) Asian river fishes in the Anthropocene:
threats and conservation challenges in an era of rapid
environmental change. J Fish Biol 79:1487−1524
Everard M, Kataria G (2011) Recreational angling markets
to advance the conservation of a reach of the Western
Ramganga River, India. Aquat Conserv 21:101−108
Giam X, Ng TH, Lok AF, Ng HH (2011) Local geographic
range predicts freshwater fish extinctions in Singapore.
J Appl Ecol 48:356−363
Helfman G (2007) Fish conservation. Island Press, Washing-
ton, DC
Hora SL (1943) The game fishes of India. XVI. The mahseers
or the large-scaled barbels of India. 9. Further observa-
tions on mahseers from the Deccan. J Bombay Nat Hist
Soc 44:1−8
Jayaram KC (1997) Nomenclatural and systematic status of
Barbus mussullah Sykes, 1839. J Bombay Nat Hist Soc
Khare P, Mohindra V, Barman AS, Singh RK, Lal KK (2014)
Molecular evidence to reconcile taxonomic instability in
mahseer species (Pisces: Cyprinidae) of India. Org Divers
Evol 14:307−326
Knight JDM, Rai A, D’souza RKP (2013) On the identities of
Barbus mussullah Sykes and Cyprinus curmuca Hamil-
ton, with notes on the status of Gobio canarensis Jerdon
(Teleostei: Cyprinidae). Zootaxa 3750:201−215
MacDonald ASJ (1948) Circumventing the Mahseer. Natraj
Publishers, Dehra Dun
McClenachan L (2009) Documenting loss of large trophy fish
from the Florida Keys with historical photographs. Con-
serv Biol 23:636−643
McClenachan L, Ferretti F, Baum JK (2012) From archives to
conservation: why historical data are needed to set base-
lines for marine animals and ecosystems. Conserv Lett
Millennium Ecosystem Assessment (2005) Ecosystems and
human well-being: wetlands and water synthesis. World
Resources Institute, Washington, DC
Nautiyal P (2014) Review of the art and science of Indian
mahseer (game fish) from nineteenth to twentieth cen-
tury: road to extinction or conservation? Proc Natl Acad
Sci India Sect B (Biol Sci) 84:215−236
Ogale SN (2002) Mahseer breeding and conservation and
possibilities of commercial culture. The Indian experi-
ence. In: Petr T, Swar DB (Eds) Cold water fisheries in the
Trans Himalayan countries. FAO Fish Tech Pap 431.
FAO, Rome, p 193−212
Ogale SN, Kulkarni CV (1987) Breeding of pond-raised
hybrids of mahseer fish, Tor khudree (Sykes) and Tor tor
(Ham.). J Bombay Nat Hist Soc 84:332−335
Pinder AC, Raghavan R (2013) Conserving the endangered
mahseers (Tor spp.) of India: the positive role of recrea-
tional fisheries. Curr Sci 104:1472−1475
Pinder AC, Raghavan R, Britton JR (in press) Efficacy of
angler catch data as a population and conservation
monitoring tool for the flagship mahseer fishes (Tor
spp.) of Southern India. Aquat Conserv, doi: 10.1002/
Raghavan R, Ali A, Dahanukar N, Rosser A (2011) Is the Dec-
can Mahseer, Tor khudree (Sykes, 1839) (Pisces: Cyprini-
dae) fishery in the Western Ghats Hotspot sustain able?
A participatory approach to stock assessment. Fish Res
Raghavan R, Dahanukar N, Tlusty MF, Rhyne AL, Krishna
Kumar K, Molur S, Rosser AM (2013) Uncovering an
obscure trade: threatened freshwater fishes and the
aquarium pet markets. Biol Conserv 164:158−169
Raghavan R, Dahanukar N, Philip S, Iyer P, Kumar B, Daniel
BA, Molur S (2015) Conservation status of freshwater
decapod crustaceans in the Western Ghats of India: an
exceptional region of freshwater biodiversity. Aquat
Conserv Mar Freshw Ecosyst 25: 259–275
Sehgal K (1999) Coldwater fish and fisheries in the Western
Ghats, India. In: Petr T (ed) Fish and fisheries at higher
altitudes: Asia. FAO Fish Tech Pap 385. FAO, Rome,
p 103
Shanmukha SN (1996) Status of mahseer fishery in Karna-
taka. Fish Chimes 15:26−29
Thomas HS (1873) The rod in India. C. Stolz, Mangalore
TWFT (Trans World Fishing Team) (1984) Quest for a leg-
endary fish. International Book Distributors, Dehra Dun
Editorial responsibility: Uwe Krumme,
Rostock, Germany
Submitted: October 13, 2014; Accepted: February 21, 2015
Proofs received from author(s): May 5, 2015
... At this point, the taxonomic identity of these phenotypes remained unclear and the fish were referred to only as Tor spp. Subsequent analyses showed that the catches of these two mahseer phenotypes could be decoupled temporally, and demonstrated that there had been a comprehensive shift in the mahseer community structure over the duration of the study period (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) (Pinder, Raghavan, & Britton, 2015b). Numerical catch rates of the blue-finned phenotype had increased substantially over time, whereas the hump- It was at this juncture that it became apparent that further investigation was needed into the blue-finned mahseer phenotype that had dominated catches in the latter years of the recreational fishery. ...
... This was because when historical images of Cauvery mahseer were viewed in angling books, they were allwithout failthe hump-backed phenotype (Boote & Wade, 1992;TWFT, 1984;Wilson, 1999), with the earliest photographic records of the same species dating back to 1919 (Wild Life, 1977). Following some initial investigations by the authors of Pinder et al. (2015aPinder et al. ( , 2015b, there was conclusive evidence that the study reach had been stocked with hatchery-reared mahseer since 1976, when the Tata Electric Company (TEC) had initially gifted large numbers (10 000) of blue-finned mahseer fingerlings to the Wildlife Association of South India (WASI). These fingerlings had been produced at Tata's Lonavla hatchery in Maharashtra and then were used to stock the controlled angling sections of the Cauvery River (Wild Life, 1976). ...
... Although Pinder et al. (2015aPinder et al. ( , 2015b had demonstrated that the hump-backed mahseer, endemic to the Cauvery River, was now highly imperilled, the lack of a valid scientific name impeded the more formal assessment of its conservation status. This was only overcome following the taxonomic determination of the hump-backed mahseer as T. remadevii by Pinder, Manimekalan, et al. (2018). ...
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• The mahseer (Tor spp.) fishes of South and Southeast Asia are iconic megafaunal species that are highly valued by recreational anglers. Knowledge on their populations is limited owing to the challenges associated with sampling these large‐bodied fishes (>50 kg) in remote monsoonal rivers. • Despite its global iconic status among recreational anglers, the hump‐backed mahseer of the Cauvery River (South India) lacked a valid scientific name and was on a trajectory towards extinction until its rapidly declining population status was established by analyses of angler catch records. • Angling records from 1998 to 2012 showed that mahseer catch rates had increased in this period. The resulting publication in Aquatic Conservation (AQC) highlighted the positive role of catch‐and‐release angling in providing information on data‐poor species. However, further analyses showed that these catches comprised not one but two distinct phenotypes. • Before 1993, all mahseer captured were hump‐backed; since then, a blue‐fin phenotype appeared in catches and subsequently dominated them. These results triggered further studies indicating that the hump‐backed mahseer was the endemic Tor remadevii and that the blue‐fin was the invasive Tor khudree, introduced in 1976 and then stocked periodically from hatcheries. • The initial AQC publication successfully demonstrated the high value of organized angling as a monitoring tool for data‐poor fishes and its application to assessing the temporal population patterns of large‐bodied fishes in monsoonal rivers. It was also the catalyst for initiating subsequent studies on T. remadevii that, together, enabled its recent assessment as ‘Critically Endangered’ on the International Union for Conservation of Nature (IUCN) Red List. In the absence of the AQC paper, and the subsequent studies that it triggered, it is highly probable that the species would have remained on a trajectory towards rapid extinction. Instead, the first major steps to safeguarding its future have been taken.
... A decline in their population dates back to the mid-2000s when catches gradually decreased (Pinder et al. 2015b). Additionally, no recent study evaluating their population size and hexagonolepis began to appear on YouTube in 2017 and attained a peak in 2022. ...
Megafish mahseers popularly known as the 'tiger of rivers', are the dream catch of recreational anglers in India. The present study explored the Recreational Angling (RA) videos of five mahseer species Tor khudree (deccan mahseer), T. putitora (golden mahseer), T. remadevii (humpback mahseer), T. mosal (mosal mahseer) and Neolissochilus hexagonolepis (chocolate mahseer) recorded from India and uploaded on the social media platform YouTube from January 2010 to October 2022. We did not come across any RA videos of T. mosal and T. remadevii on YouTube hence further analyses were carried out on the remaining three focal species. No seasonality was observed in the frequency of RA videos uploaded on YouTube and T. khudree attracted the highest number of views per video. Catch and Release (C&R), an ethical RA practice was noticeably low in the case of N. hexagonolepis. The size of the catch was found to be positively associated with the social engagement received by the RA videos of all the three mahseer species focused. Angler and angling-related remarks and words associated with the emotion 'trust' dominated the comments received by the videos. The results are discussed in light of the trending discourses on developing social media data as a complementary tool for monitoring and managing RA and conserving fish.
... The frequency and duration of high and low pulses are critical to supporting the migratory behaviour of fish during the spawning season (Wang, 2016). This has also been validated by some studies that have indicated that after the construction of reservoirs, the reduction in flows and changes in natural flow pulses threatened the survival of migratory fish species Tor pitutora in the Cauvery basin (Pinder et al., 2015). In addition, variations in fish assemblage structures have likely been affected since the structures are strongly associated with mean daily flows, base flow, number of zero-flow days and high-flow pulses (Arthington et al., 2014;Anderson et al., 2006;Perkin and Bonner, 2011). ...
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Study region: Upper Cauvery river basin, India Study focus: Reservoir construction is one of the major contributors to changes in natural river flow regime characteristics. This study aims to understand the hydrological alterations resulting from the construction of reservoirs and water abstraction in the upper regions of the basin. The impacts of dams on river flow regimes where data is available only for periods after the construction of the dams is assessed. A landscape-based hydrological model, FLEX-Topo, is used to model the flows contributed by the upstream and downstream areas of four major reservoirs in the study area. A separate reservoir operation model is developed for each of the reservoirs. Next, the hydrological model is integrated with the reservoir model and the modelled flow at the downstream streamflow gauging station of each of the corresponding four sub-basins is calibrated. The modelled flow regimes with and without reservoirs are then compared using the indicators of hydrological alterations to understand the degree to which the flows have been altered by the reservoirs. New hydrological insights for the region: The results indicate that flow regimes have been modified from their natural state following reservoir impoundment and water abstractions. Significant impacts are observed in median monthly flow, 1-day minimum flow and low pulses. Such information could provide a reference to water managers to replicate the natural flow regimes, help sustain natural biota and thus contribute toward the sustainable management of river basins in India.
... Studies based on catch per unit effort (CPUE) reveals that the population of Hump-backed Mahseer (Tor remadevii), which is endemic sh has declined signi cantly over past few decades and now is listed as an endangered species. Many other endemic sh species are amongst the endangered or vulnerable species list (Molur et al., 2011;Pinder et al., 2015). A reduction in the population of several food sh species has been recorded upstream, and post construction of the Mettur dam. ...
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In order to address the sustainability challenges emerging from interdependencies in water, energy, food nexus, in recent years ecosystem services have been identified as an important link in the nexus. Ecosystem services are essential for environmental sustainability and for provision of natural resources in WEF sectors and its degradation due to climate change and socio-economic development impacts resource security in all sectors creating a feedback loop of exploitation. This study highlights the need to integrate freshwater ecosystem health in planning development strategies as sustainable freshwater ecosystem is vital for climate change resilient future. Integrated hydrological models have been widely used to identify scenarios with optimal economic benefits in agriculture, energy and urban sectors from a water development project, in this research we have used GWAVA model to assess the impacts of changes in water use efficiency, land use change, population growth and climate change on water resources and ecologically relevant hydrological regime indicators at a basin scale. The analysis of model stimulated stream flows was used to compare the sensitivity of water resource availability induced by natural or anthropogenic changes at a sub-catchment scale. The results suggest significant uncertainties in availability and use of river water resources in the mid-century, however, aligned with the global and national climate change commitments, results shows that demand side management of water and sustainable land use management can mitigate immediate consequences of climate change on river health.
... Such data were used previously in studies to obtain a rough estimate of the community composition of large lowland rivers where other capture methods are rather difficult or inefficient (Jones et al., 1995). Some studies have used this approach to monitor flagship species (Tor spp., Cyprinidae) in the Cauvery river, India (Pinder, Raghavan & Britton, 2015a;Pinder, Raghavan & Britton, 2015b) or invasive fish species (Hargrove et al., 2015) and to estimate population structure (Weiss-Glanz & Stanley, 1984;Mosindy & Duffy, 2007). ...
• In the past, sturgeons played an important role in commercial and recreational fisheries in the Danube River and its tributaries. Human impacts in the Danube River Basin coupled with exploitation of sturgeon stocks led to all species being either locally extinct, critically endangered or of unknown status. • Sterlet (Acipenser ruthenus, Linnaeus 1758) is the last known sturgeon species occurring in the upper and middle Danube; however, the population of this species is considered unbalanced and decreasing since the beginning of the twenty‐first century. • The decline of sturgeon stocks has been noted before owing to their economic importance. With commercial fisheries being forbidden in the Slovak section of the Danube River, there is generally no information available about the status of what is considered a local population. • Databases containing recreational catch of sterlet (2003–2018) and historical records of commercial harvest (1961–1990) were used to describe the trend in the weight and number of sterlet caught over the following years. • Modelling indicated that the number of fish caught each year appears to be lower, while the average weight of each individual is increasing. This might suggest that the population is ageing. • Although older individuals can contribute a great deal more to spawning because they produce a greater number of eggs, several problems are apparent. The number of spawners might be decreasing as a result of bycatch or fishing, their ability to spawn might be obstructed, or annual recruitment may fail owing to unpredictable events. • Although restocking programmes are in place to help maintain the sterlet population in the Danube River, their efficiency seems to be drastically low. In fact, restocking could be of little value unless studies on the availability of key habitats are conducted and their protection and restoration are ensured.
... A specific need to assess in detail the preferences and awareness among C&R anglers regarding the targeting of native and non-native fishes, to understand the extent to which anglers target non-native fish species (Nguyen et al., 2013), and to estimate support for stocking to enhance recreational fishing (Granek et al., 2008). Large-scale stock replenishment of various "species" of mahseer has been carried out in the Western Ghats region, particularly in the Cauvery River (Ogale, 2002), which has resulted in the proliferation of hybrids and the suspected decline of native lineages (Pinder et al., 2015). ...
... For example, in the River Trent, England, angler catch statistics monitored changes in the fish assemblage in relation to improvements in water quality (Cooper & Wheatley, 1981;Cowx & Broughton, 1986). More recently, catch statistics from individual anglers were used to assess the population status of mahseer fishes (Tor spp., Cyprinidae) in the River Cauvery, India (Pinder, Raghavan, & Britton, 2015a,2015b). An issue with angler-based data is that they tend to be biased for specific species and size ranges (Amat Trigo, Gutmann An alternative method to using these online databases is monitoring the distribution of fishes via community science, particularly via social media platforms. ...
Freshwater ecosystems constitute only a small fraction of the planet's water resources, yet support much of its diversity, with freshwater fish accounting for more species than birds, mammals, amphibians or reptiles. Fresh waters are, however, particularly vulnerable to anthropogenic impacts, including habitat loss, climate and land use change, pollution and biological invasions. This environmental degradation, combined with unprecedented rates of biodiversity change, highlights the importance of robust and replicable programmes to monitor freshwater fish. Such monitoring programmes can have diverse aims, including confirming the presence of a single species (e.g., early detection of alien species), tracking changes in the abundance of threatened species, or documenting long-term temporal changes in entire communities. Irrespective of their motivation, monitoring programmes are only fit for purpose if they have clearly articulated aims and collect data that can meet those aims. This review, therefore, highlights the importance of identifying the key aims in monitoring programmes and outlines the different methods of sampling freshwater fish that can be used to meet these aims. We emphasize that investigators must address issues around sampling design, statistical power, species' detectability, taxonomy and ethics in their monitoring programmes. Additionally, programmes must ensure that high-quality monitoring data are properly curated and deposited in repositories that will endure. Through fostering improved practice in freshwater fish monitoring, this review aims to help programmes improve understanding of the processes that shape the Earth's freshwater ecosystems and help protect these systems in face of rapid environmental change.
Recreational angling is a major introduction pathway for large-bodied alien fishes into freshwaters, where the fish are released to enhance angling success and increase angler satisfaction, despite this often resulting in invasive populations. There is a thus a need to understand the role of these alien species in angler catches to enable more informed risk-based decisions to be made on future releases. In England, the invasive, piscivorous pikeperch Sander lucioperca has been present in rivers since the 1960s. Anglers target invasive pikeperch in fisheries where the native piscivorous pike Esox lucius is also present; this includes two rivers in the lower Severn basin, western England (main River Severn and Warwickshire Avon). To assess the contributions of invasive pikeperch to angler catches, the aim here was to compare their catches with those of native pike in the lower Severn basin in relation to angling effort and methods, abiotic conditions, and fish size. In 307 angling sessions across 16 anglers where at least one fish was captured, 428 pike and 266 pikeperch were captured. In a sub-set of data from six anglers who submitted catch returns that included non-capture sessions, 78 % of sessions resulted in the capture of at least one pike or pikeperch. Catch rates of pike were significantly higher than pikeperch in the main River Severn but not the Avon. Captured pike were significantly larger than pikeperch, but pikeperch were larger relative to the maximum size each species reaches in England. Lures generally captured more pike than any other method, with these fish tending to be smaller than those caught on other methods; these patterns were not evident in pikeperch. Both species were captured across a broad range of river flow conditions (Q6 to Q99). Only 19 % of successful angling sessions resulted in the capture of both species, suggesting some species selectivity by anglers. These results emphasise that alien fish species can provide important angling resources in recreational fisheries, although management decisions on future introductions should still consider their ecological risks.
Cambridge Core - Ecology and Conservation - Freshwater Biodiversity - by David Dudgeon
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The diminished growth and stunting of the deccan mahseer, Tor khudree, a mega-fish, endemic to peninsular India is recorded for the first time under high-density laboratory conditions, and its implications for conservation and aquaculture discussed.
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Globally, riverine fish face many anthropogenic threats including riparian and flood plain habitat degradation, altered hydrology, migration barriers, fisheries exploitation, environmental (climate) change, and introduction of invasive species. Collectively, these threats have made riverine fishes some of the most threatened taxa on the planet. Although much effort has been devoted to identifying the threats faced by river fish, there has been less effort devoted to identifying the factors that may hinder our ability to conserve and restore river fish populations and their watersheds. Therefore, we focus our efforts on identifying and discussing 10 general factors (can also be viewed as research and implementation needs) that constrain or hinder effective conservation action for endangered river fish: (1) limited basic natural history information; (2) limited appreciation for the scale/extent of migrations and the level of connectivity needed to sustain populations; (3) limited understanding of fish/river-flow relationships; (4) limited understanding of the seasonal aspects of river fish biology, particularly during winter and/or wet seasons; (5) challenges in predicting the response of river fish and river ecosystems to both environmental change and various restoration or management actions; (6) limited understanding of the ecosystem services provided by river fish; (7) the inherent difficulty in studying river fish; (8) limited understanding of the human dimension of river fish conservation and management; (9) limitations of single species approaches that often fail to address the broader-scale problems; and (10) limited effectiveness of governance structures that address endangered river fish populations and rivers that cross multiple jurisdictions. We suggest that these issues may need to be addressed to help protect, restore, or conserve river fish globally, particularly those that are endangered.
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Mahseer ( Tor spp.) are flagship fishes in South Asian rivers. Their populations are threatened through poaching and habitat disturbance, yet they are highly prized game fishes due to their large size, appearance and sporting qualities. The international recreational angling community has frequently been cited as playing a vital role in conserving these fishes while also providing economic benefit to poor rural communities. Owing to a lack of scientific data and the considerable challenges associated with monitoring fish populations in large monsoonal rivers, efforts to determine the long‐term trends in their populations has focused on sport‐fishing catch records. Here, catch data collected between 1998 and 2012 from Galibore, a former fishing camp on the River Cauvery, Karnataka, India, were analysed to determine the catch per unit effort (CPUE – by number and weight) as an indicator of relative fish abundance, along with the size structure of catches. This fishery operated a mandatory catch‐and‐release (C&R) policy, and provided the fish community with protection from illegal fishing. Between 1998 and 2012, 23 620 hours fishing effort were applied to catch and release 6161 mahseer, ranging in size from 1 to 104 lbs (0.45–46.8 kg) in weight. Across the period, CPUE in number increased significantly over time with a concomitant decrease in CPUE by weight, revealing strong recruitment in the population and a shift in population size structure. This suggests a strong response to the C&R policy and the reduction in illegal fishing, indicating that conservation strategies focusing on the beneficial and negative aspects of exploitation can be successful in achieving positive outcomes. These outputs from angler catch data provide insights into the mahseer population that were impossible to collect by any alternative method. They provide the most comprehensive analysis of a long‐term dataset specific to any of the mahseer species across their entire geographical range and demonstrate the value of organised angling as a conservation monitoring tool to enhance biological data, and inform conservation and fishery management actions. Copyright © 2014 John Wiley & Sons, Ltd.
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The mahseers are an important group of fishes endemic to Asia with most species considered threatened. Conservation plans to save declining wild populations are hindered by unstable taxonomy, and detailed systematic review could form a solid platform for future management and conservation. D-loop and cytochrome c oxidase I (COI) mtDNA sequences were examined in nine mahseer species of Tor, Neolissochilus, and Naziritor. Pseudogenes amplified in a portion of the species limited the utility of the D-loop region. ABGD analysis, NJ, ML, and MP methods and genetic distance (TrN + I + G) using COI data revealed concordant species delimiting patterns. The three genera were monophyletic, separated as distinct clades (TrN + I + G 0.064 to 0.106), and Naziritor was flagged as a separate genus, distinct from Puntius (TrN + I + G 0.196). Out of seven nominal species known for Tor cogeners from India, only five were recovered with mtDNA data (TrN + I + G 0.000 to 0.037) and two species could not be distinguished with the molecular data set employed. Tor mosal, synonymized as Tor putitora, was rediscovered as a distinct species (TrN + I + G 0.031) based on its type locality. Tor mussulah was confirmed as a separate species (TrN + I + G 0.019 to 0.026). Two valid species, Tor macrolepis and T. mosal mahanadicus, were not distinct from T. putitora (TrN + I + G 0.00). The high divergence with mtDNA data failed to validate T. mosal mahanadicus as a subspecies of T. mosal (TrN + I + G 0.031). Morphological outliers discovered within the distribution range of Tor tor (TrN + I + G 0.022 to 0.025) shared the same lineage with T. putitora (TrN + I + G 0.002 to 0.005), indicating a new extended distribution of the Himalayan mahseer T. putitora in the rivers of the Indian central plateau. The findings indicate the need for integrating molecular and morphological tools for taxonomic revision of the Tor and Naziritor genera, so that taxa are precisely defined for accurate in situ and ex situ conservation decisions.
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Mahseer species, the national heritage of India are globally acclaimed sport and table fish. Some mahseer species are now assessed as ‘endangered’, making it imperative to review historical and current state of knowledge on sport-related facets, taxonomy, fisheries ecology, biology, culture and conservation efforts. The review also examines the shortfalls in knowledge base and suggests issues that need to be addressed in future. The protection and conservation measures have fallen short of expectations as the pace of implementing mega-developmental projects exceeds natural recruitment rate of mahseers and lack of facilities for assisted propagation, at larger scale.
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Aim: Global-scale studies are required to identify broad-scale patterns in the distributions of species, to evaluate the processes that determine diversity and to determine how similar or different these patterns and processes are among different groups of freshwater species. Broad-scale patterns of spatial variation in species distribution are central to many fundamental questions in macroecology and conservation biology. We aimed to evaluate how congruent three commonly used metrics of diversity were among taxa for six groups of freshwater species. Location: Global. Methods: We compiled geographical range data on 7083 freshwater species of mammals, amphibians, reptiles, fishes, crabs and crayfish to evaluate how species richness, richness of threatened species and endemism are distributed across freshwater ecosystems. We evaluated how congruent these measures of diversity were among taxa at a global level for a grid cell size of just under 1°. Results: We showed that although the risk of extinction faced by freshwater decapods is quite similar to that of freshwater vertebrates, there is a distinct lack of spatial congruence in geographical range between different taxonomic groups at this spatial scale, and a lack of congruence among three commonly used metrics of biodiversity. The risk of extinction for freshwater species was consistently higher than for their terrestrial counterparts. Main conclusions: We demonstrate that broad-scale patterns of species richness, threatened-species richness and endemism lack congruence among the six freshwater taxonomic groups examined. Invertebrate species are seldom taken into account in conservation planning. Our study suggests that both the metric of biodiversity and the identity of the taxa on which conservation decisions are based require careful consideration. As geographical range information becomes available for further sets of species, further testing will be warranted into the extent to which geographical variation in the richness of these six freshwater groups reflects broader patterns of biodiversity in fresh water.
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Intergenerational loss of information about the abundance of exploited species can lead to shifting baselines, which have direct consequences for how species and ecosystems are managed. Historical data provide a means of regaining that information, but they still are not commonly applied in marine conservation and management. Omission of relevant historical information typically results in assessments of conservation status that are more optimistic, recovery targets that are lower, and fisheries quotas that are higher than if long-term data were considered. Here, we review data and methods that can be used to estimate historical baselines for marine species including bony fishes, sharks, turtles, and mammals, demonstrate how baselines used in management change when historical data are included, and provide specific examples of how data from the past can be applied in management and conservation including extinction risk assessment, recovery target setting, and management of data-poor fisheries. Incorporating historical data into conservation and management frameworks presents challenges, but the alternative—losing information on past population sizes and ecological variability—represents a greater risk to effective management of marine species and ecosystems.
Freshwater invertebrates receive relatively little publicity and conservation attention, in spite of their key role in aquatic food webs and ecosystem functioning. Decapod crustaceans such as caridean shrimps and gecarcinucid freshwater crabs comprise some of the most poorly known aquatic taxa, even in exceptional regions of freshwater biodiversity and endemism, such as the Western Ghats mountains of peninsular India. An analysis was carried out to understand distribution patterns and identify priority areas for decapod crustacean conservation in the Western Ghats region based on conservation status data retrieved from the IUCN Red List of Threatened Species. The Western Ghats region is home to 49 species and six sub‐species of caridean shrimps (69% endemism) in four genera and two families, and 39 species of gecarcinucid crabs (92% endemism) in 14 genera. This diversity is probably an underestimate given the lack of biotic surveys and taxonomic research carried out on these groups. Three species (3%) of decapod crustaceans from the Western Ghats region are threatened with extinction, while more than half (51%; 48 species) are Data Deficient. The uncertainty regarding the true extinction risk of such a high number of Data Deficient species could hamper conservation efforts as well as policy development and implementation. Forty sites in the Western Ghats region are priorities for the conservation of decapod crustaceans, of which only seven lie within the existing network of protected areas. The specialized natural history and point endemic nature of many species of freshwater decapods, together with escalating human impacts on their aquatic ecosystems in the Western Ghats, makes conservation and management of these threatened and poorly‐known species an immediate and urgent challenge. Copyright © 2014 John Wiley & Sons, Ltd.
The identity and generic placement of Barbus mussullah Sykes, the type species of Hypselobarbus Bleeker, have for long been unclear, variously having been considered a synonym of Cyprinus curmuca Hamilton or a species of Tor Gray or Gonoproktopterus Bleeker. Here, through a re-examination of the original descriptions and the examination of specimens from western peninsular India, we redescribe H. mussullah and show that Hypselobarbus is a valid genus, of which Gonoproktopertus is a junior synonym. Hypselobarbus mussullah is distinguished from all other species of Hypselobarbus by possessing both rostral and maxillary barbels; having the last simple dorsal-fin ray weak and smooth; the lateral line complete, with 41 +1 pored scales; 9/1/4 scales in transverse line between origins of dorsal and pelvic fins; and 5½ scales between lateral line and anal-fin origin. Species of Hypselobarbus are distinguished from other genera of Cyprinidae by possessing long, branched gill rakers and the anal fin distally rounded in adults. Hypselobarbus canarensis was found to be a valid species and H. kurali is considered its synonym. Hypselobarbus canarensis can be distinguished from all congeners by possessing both rostral and maxillary barbels; having the last simple dorsal-fin ray weak and smooth; the lateral line complete, with 40-42+1 pored scales; ½7-½8/1/3½ scales in transverse line from dorsal-fin origin to pelvic-fin origin; 4½ scales between lateral line and anal-fin origin. Hypselobarbus kolus is considered a synonym of H. curmuca, which is redescribed: it is distinguished from all congeners by possessing maxillary barbels only; the last simple dorsal-fin ray weak and smooth; 41-43+1 lateral-line scales; 9-10/1/4½-5 scales in transverse line between origins of dorsal and pelvic fins; and 5½-6 scales between lateral line and anal-fin origin.
The 15 750 valid described species of freshwater fishes comprise around 25% of living vertebrate species diversity, and are a key economic and nutritional resource for people globally. However, information on the conservation status and distribution of freshwater fishes in The IUCN Red List of Threatened Species™ (Red List) has been extremely limited until recently. Over the last 10 years, the International Union for Conservation of Nature (IUCN) Global Species Programme Freshwater Biodiversity Unit has made significant progress to fill this information gap. From a base of only 660 freshwater-fish species assessed on the Red List in 2002, a further 5125 species assessments have now been completed. As of 2011, 60 freshwater-fish species are thought to be Extinct, eight are Extinct in the Wild and 1679 are threatened with extinction. This information, combined with new work to identify important sites for freshwater fishes, will help the world's zoos and aquariums identify potential targets (species or areas) for in situ and ex situ conservation programmes.