File picture of Vietnamese catfish

Guwahati, June 25: The campaign against illegal migration on land continues, but the one against aliens underwater has reached its climax.

Worried over the prospect of foreign species of fish annihilating the indigenous varieties, the Assam government has clamped a ban on the practice of rearing these for commercial gain.

Several alien species of fish are considered a threat to local varieties. These include the Thailand magur, telapia and bighead.

Minister of state for fisheries Etuwa Munda today said the ban had been clamped solely to protect indigenous species of fish from the predatory alien varieties. He warned fish farmers against rearing such species, saying the government was serious about enforcing the ban and would take legal recourse, if necessary.

He stressed the need to raise awareness among fish farmers and motivate them to abide by the ban.

Assam’s annual fish production is about 1.61 lakh tonnes, as against the estimated demand of 2.73 lakh tonnes. The Thailand magur, a variety of African catfish, found its way into ponds across Assam from Bangladesh in the mid-Nineties. The species is reared by a large section of fish farmers because it is a lucrative proposition.

The Thailand magur is much bigger than the Asian magur, which is an indigenous species, and hence fetches more profit for fish farmers.

The history of the species dates back to the 1950s, when the French started rearing the African catfish in the Indo-China region. It reached Thailand from Vietnam sometime in the Eighties and Bangladesh in 1991, before finding its way into Assam and West Bengal.

The Asian catfish, locally known as magur, is an air-breathing fish and known for its nutrition content and therapeutic value. Officials of the state fisheries department have started a campaign to create awareness among fish farmers about its superiority in terms of nutrition over the Thailand magur.

An official said the Thailand magur was popular because a one-kg fish of the species could lay enough eggs to produce one lakh fingerlings, while an Asian magur of the same size could not produce more than 6,000 fingerlings. However, the Thailand magur’s predatory instincts preclude the possibility of rearing other species of fish in the same pond.