BENGALURU: It is not a one-day task or one man’s job to bring back a critically endangered species from the brink of extinction, but it surely takes one person to start the exercise. Retired Principal Chief Conservator of Forests Sanjai Mohan is working with a team of experts and staffers from the Karnataka forest and fisheries department to save the critically endangered Hump-Backed Mahseer (HBM), endemic to the Cauvery river, from becoming extinct.
“I had conceptualised the project when I was the PCCF, but over time with other things, this took the backseat. Now I want to ensure the project does not fold up, and the fish species survives,” Mohan said.
Usually, efforts are made to save large species like cheetahs, dolphins, tigers and elephants, but lesser known species, more so the aquatic kinds, are not given much importance. The Mahseers, especially the HBM, that we are working on, are very important to ensure a healthy and clean Cauvery river, he said.
Two years ago, captive breeding programmes were started with the help of the fisheries department and experts to raise its population, but little success was achieved as most of them were unable to acclimatize to the new environment. The method, however, helped understand the problems. The teams were able to hold the HBM in captivity for two long years.
Studying the HBM’s lifecycle
Explaining the importance of the HBM and the breeding exercise, Naren Sreenivasan, conservation biologist with Wildlife Association of South India (WASI), who is also working on the project with Mohan, said parallelly, they are studying the breeding, migration and feeding cycle of the HBM through telemetric studies in the Cauvery river. They have fitted telemetric devices on 13 HBM fish for the study. Eleven locations in the Cauvery have also been identified where the fish, after in-breeding, can be re-released, but most of the locations are upstream.
Studies have shown that the HBM needs elevation gradient sites, with high rapids and pools with suitable water temperatures for breeding. They lay their eggs during the monsoon in these locations and then move downstream. So protecting these sites is crucial, especially from upcoming infrastructure projects on the Cauvery river, said experts working on the project.
“HBM cannot be introduced in any other water body. The natural terrain and climate are ideal for the species to survive and thus, all efforts are being made to revive them. Protection of other species is essential for a healthy ecosystem. Also, if Bengaluru has to continue to get good quality drinking water, protection and revival of the Mahseer is essential,” Mohan said.
5 endemic species in India
Globally, there are 16 Mahseer species, of which eight are in India. Of these, five are endemic, and one is the HBM found in the Cauvery. Data ascertained by researchers from 1870s, due to construction of dams and other infrastructure projects, the HBM is now limited to small pockets in the Moyar river in Bandipur Tiger Reserve, Dubare Reserve Forest in Madikeri, Cauvery Wildlife Sanctuary and Pambar, a tributary of the Amaravathi river in Kerala.
With the population now dispersed and cross-breeding taking place, there is a need to identify the pure gene pool while captive breeding the HBM. For this, the help of experts from the Indian Council for Agricultural Research -- National Bureau of Fish Genetic Resources, Lucknow, is also being taken.
The water quality in the Cauvery river is good. However, the rising water temperature is becoming a worry. Ideally, for healthy aquatic life, the temperature should not be over 26 degree Celsius, but in summer, water in the Cauvery touches over 30 degree Celsius. Limited human interface and letting nature do its course will correct it, Sreenivasan said.
HBM is a flagship species of the Cauvery river. It is also an integral part of the river’s ecosystem as it feeds on vegetation and fish. Protecting it will help not just protect the water body, but also the other 200-odd fish species found in the river, which is Karnataka’s lifeline, Mohan said.