Scientists save endangered Gotali fish from extinction

Once widely consumed and prized for its taste, Gotali fish -- an indigenous species declared endangered by the International Union for Conservation of Nature (IUCN) in 2015 -- is now on the path to revival.

Scientists at the Bangladesh Fisheries Research Institute (BFRI) freshwater substation in Saidpur, Nilphamari, have successfully developed a technique for its artificial breeding and fry production, offering new hope for its conservation.

The Gotali fish (Crossocheilus latius), a member of the Cyprinidae family, was once abundant in the Teesta basin, the hilly streams of Mymensingh, and the river systems of Sylhet.

However, its population has drastically declined due to water pollution, the use of destructive fishing techniques -- such as current nets and electric fishing -- and the adverse effects of climate change.

According to BFRI, Bangladesh is home to 261 freshwater fish species, 64 of which are critically endangered.

BFRI Principal Scientific Officer Azhar Ali said efforts to conserve Gotali's gene pool began in 2023, with a five-member team conducting extensive research.

Scientists collected live specimens (5-6 grammes) from the Teesta and Buri Teesta rivers during April-May and preserved them in research ponds for domestication and adaptation before breeding.

"During the breeding season (July-August), mature male and female Gotali fish were transferred to hatchery tanks with gentle water flow and injected with synthetic hormones," said Senior Scientific Officer Sonia Sharmin.

After 8-10 hours, females laid eggs, which were fertilised by males, leading to the successful production of fish fry.

The fry were initially fed a mixture of boiled egg yolk and water and later transferred to nursery ponds after 6-7 days. 

Over 45-60 days, the fry reached 5-6cm in size, with a survival rate of 65-70 percent.

The research was led by Azhar, alongside Sonia, Maliha Hossain Mou, Srebas Kumar Saha, and Md Abu Naser.

Azhar confirmed that the Gotali fry will soon be distributed to farmers, enabling private and government hatcheries to produce them commercially.

It is notable that BFRI's Saidpur freshwater substation previously received a medal in 2017 for successfully developing artificial breeding techniques for native Tengra fish.