For one of the most recognizable fish in the world, the hump-backed mahseer has struggled to hold on to a precarious existence in the River Cauvery and its tributaries, not helped by the fact that it has never had a correct scientific name. But being able to name the fish has been a long, difficult process for the team headed by Bournemouth University’s Adrian Pinder and his colleagues in Mahseer Trust.
Adrian first began to consider the status of the hump-back mahseer on a visit to fish the famous angling camp of Galibore, in 2010. He was confused by the ghillies referring to fish as golden or silver, and also that there appeared to be some significant differences in the body shape of these two fish. His conclusion was that they had to be two different species and that none of the people he was talking to could give a definitive answer about which fish was which.
There was a common understanding that two species lived in the river, called Tor musullah and Tor khudree, but when he made contact with Indian fish taxonomist, Rajeev Raghavan, he was told that Tor musullah was a mis-identification of a central Indian carp, and not a mahseer at all. Although adding more confusion to the questions in his head, this drove Adrian to search for more people who could throw light on the subject.
Mutual contacts introduced Adrian to Steve Lockett, who had, at that stage, visited most parts of the River Cauvery on repeated visits over more than ten years. Steve had especially good knowledge of the critical upstream parts of the river and smaller streams in Coorg, as well as having visited the River Moyar around Mudumalai Wildlife Sanctuary. Together, they began to shape the programme needed to allow more research to be done on the hump-backed mahseer by UK registered charity, Mahseer Trust.
Through Rajeev, a multi-disciplinary team of mainly Indian scientists was alerted to the work needing to be done. The fish had to be found, modern taxonomic data had to be collected on as many different fish as possible, including those preserved in museums, and, crucially, genetic materials had to be collected, processed in an Indian laboratory, and matched to high-quality photographs, to prove the identity of the fish.
Originally, a large carp, discovered in the Ghod River near Pune in 1839, Barbus musullah is now called Hypselobarbus mussulah and has many very significant differences from mahseer in general and the hump-backed mahseer in particular. Because some of the early explorers thought the hump-backed mahseer was the same species as Barbus mussulah, nobody carried out the careful descriptive work needed to verify the fish of the Cauvery as a distinct species. Quite simply, it was sloppy science by two famous fish scientists, Gunther and Day, to change its name to Tor mussulah, and was a mistake that was not rectified until 2016.
Tor mussulah, therefore never underwent a taxonomic study, so nobody could list the features needed to identify it. There was no valid genetic record. In short, Tor mussulah has never formally existed, except in the minds of anglers and some scientists who never checked the papers.
One of the first steps needed was to understand the history of the mahseer populations and to achieve this, Adrian studied the catch records from the angling camps at Galibore and Bheemishwari, while Steve appealed for anglers to send to him as many photos as possible of mahseer catches from the river.
Having collated all of the catch data, Adrian and Rajeev published a paper about the terrible 2004/2005 crash of the hump-backed mahseer population. To read the paper, click here: Pinder-2015.pdf
Study of the various photos, some of which dated back to early years of photography, which included fish from the main river, as well as the rivers Moyar, Bhavani and Kabbini, clearly showed that the fish often called golden mahseer, better described as the hump-backed mahseer, was exclusively the subject, at least until stocking began in the mid-1970s. After that, the so-called blue-finned mahseer, now known to be Tor khudree, which is a native of the Mula-Mutha River of Pune, in Maharastra, steadily took hold.
Adrian had enough evidence to demonstrate the change in demographics, and, crucially, the range of photos also gave some clues to how to tell the two species apart. There are three aspects of body shape that always differ between the two species:
1. The hump-backed mahseer reaches maximum body depth, or very close to it, immediately behind the head. Tor khudree reaches maximum body depth beneath the dorsal fin.
2. Tor khudree has an underslung mouth, but the hump-backed has what is known to scientists as a terminal mouth, with jaws of equal length.
3. In the foremost part of the gill cover (called the pre-opercular), there is a small kink at the lower edge, this isn’t present in blue-finned mahseer.
Careful measuring of the many features required by a modern taxonomic assessment have shown still more differences between the two species and helped to prove the identity of the hump-backed mahseer.
Safe, For Now
A series of papers published by Dr Manimekalan of Bharatiar University, Coimbatore provided another clue to where the hump-backed mahseer could be found. Pictures of fish from inside Satyamangalam Tiger Reserve, on the River Moyar, showed interesting features. Working in collaborations with Wildlife Association of South India and field support staff with Dr Manimekalan, fresh samples were taken and genetic tests proved they matched some taken from unknown fish in a number of stretches of the River Cauvery. Crucially, genetically, they were conclusively not Tor khudree. The photos showed the by now familiar features of hump-backed mahseer.
Another short description paper lead Rajeev to send a field researcher to the Pambar River, the southernmost tributary of the River Cauvery. There, samples were collected from a lesser-known mahseer, and more photos were taken. The genetic tests on these fish, linked to good photos and a full taxonomic assessment were the final keys to unlock the whole mystery.
But still, the news could not be shared until verified by independent scientific study, and samples of whole fish had to be sent to reputable collections. This process, whereby the stored sample is called a voucher specimen, ensures anybody who wishes to challenge the findings or compare to other species, can do so at any time in future. Once lodged in a reputable collection of a university or museum, it is available for future study.
In January 2016, Tata Power and Mahseer Trust jointly hosted a conference for the conservation of the hump-backed mahseer at Tata Power’s mahseer hatchery, at Lonavla, near Pune, Maharastra. Adrian and Steve represented Mahseer Trust, and presented evidence of how the introduction of blue fin Mahseer, Tor khudree, originating from Tata Power’s Lonavla Hatchery and more recently Karnataka State Fisheries Department Hatchery in Harangi, Coorg, had been pivotal in causing the collapse of the endemic hump-backed population and had pushed the species to the edge of extinction.
Steve unveiled a plan to gather support far wider than previously, in a bid to spread awareness about the plight of both fish and river, as well as starting a study regime on the population in the River Moyar. The plan was to be called Kaveri Mission, and would use the reverence felt for Goddess Kaveri as a unifying force, with the hump-backed mahseer promoted as a flagship species.
With agreement from all the partners at the meeting, Tata Power agreed to fund the proposals put forward, and work continues into 2018, to deliver the first phase of Kaveri Mission.
Following a lengthy process of writing, cross-referencing, editing and re-writing, the paper called Resolving the taxonomic enigma of the iconic game fish, the hump-backed mahseer from the Western Ghats biodiversity hotspot, India was published. In it, all of the conclusive evidence was laid out and the case was made to explain why the hump-backed mahseer of the River Cauvery finally has a name and it is Tor remadevii.
Having a valid scientific name means that the fish can now be assessed by the IUCN Red Listing committee, and it will be listed as Critically Endangered, the final step before an organism is declared Extinct in the Wild.
Step One Done, Now for the Hard Work
The naming is only the first step in helping to conserve this mighty leviathan. The River Cauvery is itself under massive pressure, due to a drive to cut the forests of Coorg which are the lifeblood by providing a steady release of water year-round. Also, destructive fishing methods have been used. These indiscriminately kill the largest, brooder fish as well as tiny fingerlings and many of the food items. Pollution becomes a greater threat as towns and cities grow ever bigger and people are careless about disposing of waste properly. Sand mining creates barren areas where the flow runs out of control, and the many organisms that rely on these areas to spawn can no longer do so.
Protecting and rehabilitating the river habitat is vital if the fish is to return and once again be a symbol of a healthy environment. With only two small breeding populations, there is an urgent need for the fish to be able to repopulate more spots and reduce the risk of a catastrophic event.
Crucially, much more work remains to be done to understand how these huge fish use their fragile habitat. While many decades of fine work on breeding mahseer means we could, given the correct breeding stock, and a suitable in-river hatching facility, allow a careful restocking programme to begin, still nobody has carried out any work to understand why successive breeding seasons in the wild have failed, or what can be done to restore this natural cycle.
It is time to bring many more, experienced scientists and conservationists into the project to conserve the river habitat and understand its newest inhabitant, Tor remadevii.
About the Author
Steve Locket, Angler, Conservationist, Education and Outreach Officer at Mahseer Trust
If you can help by offering skills, local knowledge, time or contacts, please email [email protected]
To help fund ongoing and future projects, to ensure the hump-backed mahseer, Tor remadevii does not go extinct, please visit http://mahseertrust.org/support/ and either sign-up to be a supporter of Mahseer Trust, and/or make a donation.
For more information, please follow these links:
To read the scientific paper, and spread the news on social media, click here: Resolving the taxonomic enigma of the iconic game fish.
Adrian talking about the threats the fish still faces, and why saving it is important,
Title Image - Ade Kiddell with an impressive hump-backed mahseer from Galibore. Probably the last hump-backed to be caught before the angling ban came into force in Cauvery Wildlife Sanctuary.