The Miss Kerala fish. Picture credit: Rajeev Raghavan

New Delhi, Dec. 23: A study in which conservation scientists killed more than 1,000 specimens of an endangered freshwater fish from the Western Ghats region has enraged fellow biologists who have questioned the decision to dissect so many fish.

Scientists with the Conservation Research Group at St Albert’s College in Kochi procured 1,080 specimens of Puntius denisonii, an attractive aquarium fish, and euthanised them by immersing them in ice to study their reproductive biology.

The scientists say the fish — also known as the Red Lined Torpedo Barb or Miss Kerala — which has a distinct pattern of colours, has spawned a trade for the domestic and international aquarium industry.

They estimate that about 100,000 fish are flown outside India each year, making up 65 per cent of India’s export of ornamental fish.

In the study, scientists dissected the fish to determine the proportion carrying mature eggs and helped establish that its breeding season is the post-monsoon season and not the monsoon season as had been assumed earlier.

“This is a most unfortunate way of doing science,” said R.J. Ranjit Daniels, an ecologist with Care Earth, a non-government conservation organisation in Chennai.

Daniels said careful visual examination may also be used to determine whether a fish is carrying mature eggs. “Some of our fisherfolk have been traditionally doing this. They release gravid fish back into the water,” Daniels said.

He said statistical techniques could have been used to draw the inferences through a smaller sample than the 1,080 sacrificed for the study.

Daniels has criticised the study in the journal Current Science, published by the Indian Academy of Sciences.

The Kochi study, published in the Journal of Threatened Taxa early this year, drew flak within days after its publication. A scientist with the Zoological Survey of India, K.A. Subramanian, said its inference of post-monsoon breeding of Puntius denisonii could have well been arrived at “without killing a single individual (fish)” by measuring the size class distribution of the population.

The researchers have refuted any wrongdoing and asserted that the methodology they followed was justified and the study’s findings will actually help conservation of this endangered freshwater fish.

The Kerala government currently prohibits collection of this species during the monsoon season, under the earlier assumption that the fish breeds during the monsoon months. “Our work will help the government correct the ban period on collection to the post-monsoon months, from October to January,” said Benno Pereira, a co-author of the study.

The researchers also pointed out that they had procured the live fish only from exporters who would have in any case shipped them off for aquariums. “The fish had already been taken from our biodiversity,” a biologist said.

“A shift in the period when this ban is effective from the monsoon months to the post-monsoon period could help save several million fish each year,” said K. Krishna Kumar, an expert on fish of the Western Ghats and a programme officer with the Ashoka Trust for Research in Ecology and the Environment, Alappuzha. “I think the study has achieved something important,” he told The Telegraph.

The researchers said they were hurt by the accusations from fellow scientists.

Until this study, no researcher or policy maker had bothered to confirm whether the fish bred during the monsoon season, the researchers said in an email response to Subramanian’s criticism, circulated within the fish conservation community.