Mahseer Conservation Planning Workshop In Kochi
The Mahseer Conservation Planning Workshop in Kochi commenced on April 4, 2017 with Sanjay Molur, from the IUCN Conservation Breeding Specialist Group reiterating the need for reassessment of all mahseer species in light of new information. “What we knew in 2009-10 is very different from what we know now”, said Molur.
The Workshop, a preliminary session preceding a two day conference, organized by Kerala University of Fisheries and Ocean Science witnessed the IUCN Freshwater Fish Specialist Group addressing current conservation threats for each of the species within the Tor genus, found in India. The conference presents a unique interactive opportunity to those involved in fish and river conservation across Asia.
Photo: Mahseer Trust
It was noted at the workshop that current Red Listings of fish of the genus Tor, commonly called mahseers, were last revised in 2011. Therefore, population trends were one of the key areas of discussion, with anthropogenic threats from harvest, and dam construction being viewed as the main issues.
A debate focusing on the increased number of restocking programmes currently being employed as mitigation measures in India, took place as well. The effect that these measures have had, both on wild distribution and extension of natural ranges, was discussed.
The population decline of Tor Khudree commonly known as the deccan mahseer despite focused conservation efforts through reintroductions, was also a subject of discussion. “Every ecological study carried out on T. khudree has been done on fish raised by aquaculture, it is difficult to be sure about lifestyle expectations without more study on wild populations”, said Adrian Pinder from Bournemouth University.
While scattered wild populations of mahseer might still exist within their natural distribution range, critically no remaining stocks in the type locality have been observed. Reference to type specimens is essential to ensure genetic identification which is used alongside taxonomy, as mahseers can look very similar to each other, exhibiting a diversity of morphologies.
T. Putitora, or the Himalyan mahseer is another species that has been subject to stocking efforts across its distribution in the Himalayan region. However, the general consensus amongst those present at the workshop over the fate of the mahseer was that the proposed construction of damns will further impede the survival of these species in its native rivers.
The hump-backed mahseer of the River Cauvery basin, which was previously and erroneously called T. Mussulah, found mention in the workshop due to the catastrophic decline in its population.
Although, very few studies have been carried out on the ecology of wild fish, there are enough records of fish caught by anglers between 1998 and 2012. These show that numbers of mature fish had hit a low of 0.3 per cent of catches by the time angling was banned in the protected area of Cauvery Wildlife Sanctuary, from 25 per cent in 1998 and a recorded 100 per cent prior to 1976.
Currently, there are only three small and very vulnerable stretches in the entire catchment of the Cauvery river, where hump-backed mahseer are known to breed. All three are prone to anthropogenic pressures, and the expectation is that these small populations will continue to decline under present circumstances. A complete wipe-out by a pollution event too cannot be ruled out.
The Red Listing committee is considering the status of all three species and will soon publish the conclusions of the updated deliberations.
Source: Steve Lockett, Vice Chair, Mahseer Trust