Aquatic faunal survey of Periyar Tiger Reserve reveals diversity of fish, insect species

Idukki(Kerala): The first ever aquatic multi-taxa survey in the Periyar Tiger Reserve (PTR) has revealed an exceptional diversity of predatory insects and fish spread across the various habitats and elevations of the wildlife sanctuary.

The aquatic faunal diversity in the sanctuary was assessed by around 75 experts from southern India and members of fishermen eco-development committee of PTR from May 16 to 19, a government release said on Thursday.

They assessed the various habitats of the reserve comprising the streams of the Periyar, Mullayar and Pampa basins, as well as the Periyar Lake, it said.

"Fifty-six species of fish were recorded which makes it the highest count ever from any study in the PTR conducted since the 1940s."

The number of fish species inside the various water bodies of PTR comprises close to 30 per cent of all fish species known from Kerala.

"The significance of PTR’s fish diversity is in its micro-endemism as it harbours nine species restricted to the boundaries of the reserve – all of which but one, could be recorded during the current survey," the release said.

The survey also recorded four alien or exotic fish species -- Clarias gariepinus (African Catfish) Cyprinus carpio (Common Carp), Oreochromis mossambicus (Mozambique Tilapia), and Oreochromis niloticus (Nile Tilapia).

The study also discovered at least seven new species of fish from the various tributaries inside the PTR, which requires confirmation through molecular studies.

Besides that, the survey also found four new odonate (predatory insects) species taking their total, in the PTR, to 120.

"This is the highest number of odonates ever recorded in any protected area in Kerala, and comprises 63 per cent of the odonate diversity of Kerala and around 55 per cent of the Western Ghats," it noted.

"The four new additions are Anaciaeschna martini Selys, 1897, Brachydiplax sobrina (Rambur,1842), Idionyx corona Fraser, 1921, and Idionyx minima Fraser, 1931," it said.

The release further said that the presence of the micro-endemic fish species signifies the success of the PTR's management interventions in controlling invasive species.

"This demonstrates a healthy aquatic ecosystem where native species can thrive. Immediate further studies are also planned to describe the newly encountered species," it added.

Patil Suyog Subhash Rao, the Deputy Director, East Division of PTR, stressed on the significance of the data generated from such composite assessments for the long-term management and conservation of the region.

"A follow-up survey including major terrestrial and aquatic fauna is under consideration in the inter-monsoon period," he is quoted as having said in the release.

The composite aquatic faunal survey was conducted following the management mandates of the PTR, under the special instruction of Field Director and Chief Conservator of Forests, Pramod P P, it said.