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Icon Of The Cauvery

Icon Of The Cauvery

U.K. fisheries scientist and Mahseer Trust director Adrian Pinder, tells of how the hump-backed mahseer first captured his attention, and the journey he has embarked upon to contribute towards the conservation of the endemic biodiversity of south India’s Cauvery river.

Despite its trophy status, the Cauvery river’s endemic, orange-finned, hump-backed mahseer, still lacks formal scientific description. Photo Courtesy: Adrian Pinder.

The name ‘mahseer’ first came to my attention in the late 1970s when, as a young boy, I stumbled across a photograph, the image of which is still etched in my mind, of a European gentleman standing chest deep in a majestic river with an Indian guide assisting him in cradling a gigantic fish. Along with inspiration closer to home, I have no doubt that this image contributed to igniting my obsessive fascination with fishes, which in 2010 eventually lured me to undertake my first trip to the Cauvery to acquaint myself with the mighty mahseer.

Hook, Line and Sinker

Emerging from my tent to the sweet smell of coffee and a cacophony of birdsong, the largest and reddest of suns gradually rose from the east horizon, casting an orange glow throughout the Cauvery valley and set to work on quickly burning off the morning mist which still clung to the river below me. I had only been at Galibore Nature Camp since mid-afternoon the preceding day, but had already been treated to some extraordinary wildlife, with sloth bear, mugger crocodiles, smooth-coated otter and grizzled giant squirrel (not to mention a mind-blowing array of birdlife) all putting in an appearance. As I reflected on the last few hours, I was acutely aware that this was no longer just a fishing trip. I had been abducted by the beauty of the Cauvery, and as an ecologist was already eager to return in a professional context, to uncover some of the river’s secrets.

Over the next few days (while dodging crocodiles and elephants), I observed substantial phenotypic variation in the mahseer population. The orange-finned (hump-backed) mahseer which had initially attracted me to India proved to be elusive, yet the river was teaming with an abundance of small mahseer with blue fins. In researching the identity and ecology of these fishes I was immediately confronted with conflicting and ambiguous viewpoints, and it became obvious that without some clarity, future conservation planning and effective fishery management strategies would remain severely constrained. Specifically, these observations raised the following principal questions; 1) Where had the blue-finned fish come from and why were they so abundant?; 2) What had happened to the iconic hump-backed mahseer?; 3) Which species of Tor were these fish?, and 4) What were their ecological requirements?

Despite being recognised as an area of exceptional biodiversity and endemism, approximately 50 per cent of fish species endemic to India’s Western Ghats region are reported to be threatened with extinction. In May 2015 a paper published in Endangered Species Research catapulted south India’s most iconic freshwater fish, the hump-backed mahseer, to the top of this list, attracting media attention from around the globe.

Of around 17 mahseer (Tor spp.) species known to be distributed throughout South and Southeast Asia, the giant hump-backed mahseer of India’s Cauvery river represents the largest member of the genus known to man. Capable of reaching weights in excess of 130 lbs. (58 kg.) and exceeding 1.5 m. in body length, this freshwater giant easily qualifies as megafauna (>45 kg.) and is thus afforded recognition amongst the 20 mega-fish of the world. If it were not however for the publication of A Rod in India by H. S. Thomas in 1873, this giant member of the carp family (Cyprinidae) may never have been brought to the attention of recreational anglers; a global community which perhaps paradoxically, has played a critical role in conserving several species of endangered mahseers throughout India (see Recreational Angling notes).

Waterfalls and large pools characterise the Shivasamudram reach of the Cauvery. The river was once stocked exclusively with hump-backed mahseer. Photo Courtesy: Adrian Pinder.

Unravelling the mystery

Due to their trophy status, the historic photographic record for hump-backed mahseer is extensive and I was able to recover records dating from as early as 1919. The majority of photos were sourced from the Shivasamudram and Coorg reaches of the Cauvery with additional records coming from the Kabini and Moyar tributaries. Further supporting the photographic records of anglers, tribal elders and senior angling guides have confirmed that historically the mahseer stock of the Cauvery and its tributaries was exclusively composed of fish exhibiting orange fins. Despite being referred to as mussullah (prefixed with Tor, Hypselobarbus or Barbus), this much-revered species of the Cauvery and its tributaries, still lacks formal scientific description, a valid scientific name, and recognition on the IUCN Red List.

This data also confirmed that the hump-backed mahseer is endemic to the Cauvery basin, not occurring anywhere else in the world.

Invasion of the blue-fins

In 1978, a team of British explorers (The Trans World Fishing Team) set out to investigate whether the hump-backed mahseer of the Cauvery were extant. In doing so they were invited to visit Tata Electric Company’s hatchery at Lonavala, where they were the first to document the culture of ‘a strikingly blue-finned fish’; targeted for release in the nearby rivers and reservoirs. The team then proceeded to the Cauvery river where they recorded only the endemic hump-backed mahseer. Recent genetic analysis conducted by the Mahseer Trust, has confirmed the identity of the fish cultured by Tata as Tor khudree, a species originating from Pune district and not native to the Cauvery. Tata’s ‘Project Mahseer’ was initiated in 1975 and openly reports the experimental hybridisation of mahseer species and the export of fingerlings throughout India and even to Laos. While the pioneering work and considerable skill required to produce these fish in captivity is commendable, the impact of stocking several hundred thousand fingerlings into the Cauvery (from 1975 to present date) without first establishing a baseline of the endemic mahseer and an appreciation of their ecology has now been shown to have been implicated in the collapse of the hump-backed population which is today sadly spiralling towards extinction.

In search of the elusive hump-backed mahseer, the author finds yet another blue-finned mahseer during a survey of the river this year. Photo Courtesy: Adrian Pinder.

Population threats

In March 2014, as Director of the Mahseer Trust, I hosted a two-day workshop at the Bannerghatta Nature Park. Here, leading fisheries scientists from three continents, local stakeholders, Indian naturalists and government officials convened to discuss mahseer conservation. Delegates of the workshop synthesised population threats into a broad range of individual and combined effects which included: catchment fragmentation and habitat loss, the mass construction of hydroelectric dams; water and aggregate abstraction, and diffuse and point-source pollution. With the additional prevalence of illegal and highly destructive fishing methods such as small meshed nets, the use of poisons, electricity and dynamite, mahseer already have a lot to cope with. With the threats posed by previous and future stocking with the wrong species now realised, it was the lack of knowledge regarding the natural ecology of these animals such as their migratory behaviour, functional habitat/flow requirements, diet and basic biology which stood out as knowledge gaps which continue to severely constrain the formulation of effective conservation and fishery management plans. Furthermore, without such knowledge, defining acceptable ecological flows (E-flows) and Environmental Impact Assessments (EIA) will continue to lack any scientific credibility and fail to protect these fish and the broader associated ecosystem. Despite a willingness to voluntarily invest time, money and world-class expertise into mahseer research (as evidenced by the 2014 workshop), the acquisition of licenses for foreign and indeed national scientists to work in PAs is also being made particularly difficult due to a range of legislative and bureaucratic barriers; procedures which have ironically been implemented to protect wildlife.

Future conservation prospects

The Mahseer Trust represents a collaboration of international expertise and stakeholders. It was formed to raise general awareness of the Tor genus and acts as a centralised knowledge hub for scientists, students, anglers and anyone with an interest in conserving these magnificent fish. There may still be some hope for the hump-backed mahseer as local intelligence suggests a population may still exist, isolated from competition and genetic introgression from the invasive blue-fin mahseer. If specimens can be collected, then formal taxonomic description will afford the fish a name it so deserves. Fish hatcheries (both national and local) are also geared to start culturing the Cauvery’s endemic mahseer. This however is only part of the solution; the future sustainability of stocks will require extensive scientific research to characterise the ecological requirements of these fish if seeds are to be intelligently distributed where a variety of needs, such as habitat and flows, a lack of non-native competitors and effective protection from poaching can be accommodated. What is clear is that even with the best will and investment in the world, no one organisation is capable of achieving these goals alone. To most people, fish and other aquatic fauna lie out of sight and out of mind. It rarely enters one’s consciousness that a healthy river ecology signals the general quality of water which we all rely on to sustain our very own existence. Endemic mahseer therefore represent critically imperilled flagship species, their future now dependent on the political will to bring together and support a multi-disciplinary task force of mahseer scientists, politicians and interested corporations to limit further damage to the genetic integrity of remaining stocks, and prevent the loss of this national and world renowned natural treasure.

Adrian C. Pinder’s career in fisheries research and conservation spans 25 years. He has previously worked for the U.K. government and is currently employed as Director of Environmental Consulting at Bournemouth University. Adrian also works in a voluntary capacity as Director of the Mahseer Trust, an international NGO with offices in the U.K. and India.

Further reading: The legendary hump-backed mahseer Tor sp. Of India’s River Cauvery: an endemic fish swimming towards extinction? is available online at https://www.int-res.com/abstracts/esr/v28/n1/

A well-intentioned, but misguided conservation project of the Tata group saw thousands of non-native mahseer fingerlings released into the Cauvery. These blue-finned mahseer have now rapidly ousted the native hump-backed mahseer, pushing them to the brink of extinction! Photo Courtesy: Adrian Pinder.

Recreational angling of endangered fish Though a contentious issue, it deserves unbiased appraisal to evaluate whether this practice constitutes a conservation problem or conservation action? This was the question recently posed in a paper published in Fish and Fisheries, the world’s highest ranking fisheries journal.

In examining mahseer as a case study, the authors drew attention to the work of the Wildlife Association of South India (WASI), a NGO which from 1973 took a lease on 22 km. of the Cauvery between Mutthatti and Mekedatu Gorge and developed a strictly regulated catch and release mahseer fishery. Due to the international sporting appeal of the hump-backed mahseer, anglers travelled from around the globe, injecting significant sums of money into the local economy. Using the income generated, WASI employed guards (usually rehabilitated poachers) to man anti-poaching camps. The salaries and tips earned by the local guards very quickly led to the realisation that mahseer represented their livelihoods and were thus vehemently protected from dynamite fishing. The subsequent growth in fish numbers and popularity of the fishery encouraged other NGOs such as the Coorg Wildlife Society, private individuals, and the State Government-owned Lodges and Resorts (JLR) to set up seasonal angling camps on the river during the 1980s and 1990s, leading to an industry employing angling guides, cooks, bait makers and a whole host of supporting roles, providing even greater incentive to protect the fish from illegal fishers.

But wait…. don’t fish die when they are released? A collaboration of researchers from Canada, USA, U.K. and India has recently undertaken a study to look at stress levels in mahseer after being caught on rod and line. They concluded that as a family of fish, mahseer (Tor spp.) are very robust with post-release mortality and even behavioural impairment considered to be less than five per cent.

Where does the ban on recreational angling leave the mighty mahseer? Unless Forest Departments have the capacity and will to invest in resources which guarantee protection from poachers (a system that the author has observed to be highly successful on the Ramganga river within the Corbett National Park, Uttarakhand), the absence of recreational anglers within the Cauvery Wildlife Sanctuary will result in a lack of income to local communities who will typically revert to taking the fish for food using unsustainable fishing methods such as poisons and dynamite. These illegal fishing methods may provide a quick meal but will impact all aquatic fauna and their associated predators (e.g. otters, crocodiles and birds). Furthermore, recreational anglers have proved highly effective in collecting quality data to monitor fish populations. Without their contribution of long term data, the critical status of the hump-backed mahseer would not be apparent. Lacking the continuation of this angler-derived dataset means there remains no way of tracking the future population status of endemic and non-native mahseer against the baselines already developed.

Author: Adrian Pinder, First appeared in: Sanctuary Asia, Vol. XXXV No. 10, October 2015.


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