A survey on the freshwater fishes in the rivers flowing through the Aralam Wildlife Sanctuary has found that the floods in the previous years had a drastic impact on a few species of fish, which were found in abundance here earlier.
The two-day survey was conducted as part of the wildlife survey, organised jointly by the Aralam Wildlife Sanctuary and Malabar Nature History Society and carried out by students, environmentalists, and led by Jaffer Palot, scientist, Zoological Survey of India, and C.P. Shaji, fish biologist.
The study, which focussed on the Urutty and Cheenkani rivers flowing through the sanctuary, found that there had been a drastic reduction of fishes including loaches, Malabar Spiny eel and Travancore Batasio in the rivers, Mr. Shaji told The Hindu.
He said the first survey in the sanctuary was conducted in 1995 and later in 2019. While both the surveys had found that the rivers were teeming with loaches, this time they could find only two or three fish of the species, indicating a drastic reduction in their population.
It was concluded that the such a drastic fall in the population had occurred due to the floods, which changed the river beds.
However, compared with the previous surveys, three more varieties of fish were found in the river, which took the tally of fishes found in the rivers here to 48, Mr. Shaji said.
While during the 2019 survey, only 32 species of fish were found, this increased to 45 species in 2019 and to 48 species this year. The Malabar Sucker Cat fish, which is endemic to the Western Ghats and was found in 2010 by the Zoological Survey of India, was sighted here during this survey, he said.
The other species of fish, including Malabar Barl, Flamentous Barl, Malabar Dino, and Malabar Killu have maintained their population levels and were found in abundance.
Most of the fish varieties are edible but no socio-economic survey had been done here to understand whether overfishing was another reason for the reduction of fish varieties here, he said.