It is a record for the Vembanad fish count which quantifies fish diversity in central Kerala’s Vembanad Lake every year. Volunteers and scientists counted as many as 117 fish species this year, far higher than the 55 species observed last time.
Coordinators of the fish count, including the Ashoka Trust for Research in Ecology and Environment (ATREE) and the Kerala University of Fisheries and Ocean Studies (KUFOS), announced the results at their valedictory function at KUFOS in Ernakulam on Friday.
Teams observed such a high number of fish species because they also surveyed areas north of the Thanneermukkam bund, including Arookutty, High Court, Poothotta, Murinjapuzha, and Kanakkankadavu, this year.
So far, only the southern expanse, from Punnamada to the Thanneermukkam bund, had been included in the survey.
Results
Participants observed more numbers of freshwater fish than usually seen; the recent rain could have decreased the salinity in the lake, permitting more freshwater fish presence.
However, the number of species seen in the southern region has decreased to 49 this year (versus the 55 species seen here last year), said M.K. Sajeevan (associate professor, KUFOS) as he spoke in detail about the results.
The northern region yielded 87 fish species and nine crustaceans, he said. Here, a team also observed a threadfin sea catfish Arius arius with its young in its mouth. These catfish are mouth-brooders, and carry their young in their mouth to protect them from predators.
Teams also recorded two exotic fish in the lake this time: the shortfin molly Poecilia mexicana and the moon gourami Trichopodus microlepis . The high numbers of jellyfish in the waters could be a worrying trend too, added Jojo T.D., project coordinator (ATREE, Alappuzha).
Around 120 volunteers – including students of St. Thomas College, Thrissur, and Indian Institute of Technology, Kharagpur – and scientists participated in nine boat cruises for the fish count on May 24 and 25.
“It was my first fish count and a great experience for me,” said Niveditha S., a final-year student of fisheries science at KUFOS, who took part in the fish count. “I think the count is useful because it can tell us whether fish diversity is changing over the years.”
