Mie fish farm admits using hormone disrupter

A fishery cooperative in Owase, Mie Prefecture, halted virtually all shipments of its farmed fish after learning that a farm in the region used a banned hormone disrupter as a parasite repellent, the cooperative said Saturday.

The cooperative voluntarily suspended shipments Wednesday, and no health problems have been reported.

The Fisheries Agency will visit the fish farm in Owase to determine whether the reported substance, an organic tin compound known as tributyltine (TBT), was used by fish farms elsewhere in the country.

TBT is known to prevent shellfish and seaweed from fouling fishing nets and was previously contained in an antifouling agent used as a net coating. Often referred to as a "marine herbicide," its use was banned by the Fisheries Agency in 1990 because of its adverse impact on marine ecosystems.

Owase is a major fishing town on the Pacific coast. It is part of a region that farms around 960 tons of sea bream and yellowtail each year.

The Owase fishery cooperative said one of its members had a can of TBT-laced antifouling agent at home and immersed bags of sawdust infused with the agent into its yellowtail enclosures in January last year.

"The antifouling agent was used to keep (parasite) bugs away from the fish. I knew it was harmful. I had it for a long time and was at a loss as to how I could dispose of it," the unnamed member said without explaining how long the bags were in the water. The bags have since been removed, it said.

The head of the cooperative said it was having all antifouling agents tested.

"We have offered the antifouling agents currently used by other cooperative members to a laboratory to confirm whether they are safe," the unnamed person said.

TBT is known to be barely biodegradable. Previous studies have shown that even a minute amount of the substance can trigger reproductive abnormalities, such as female shellfish growing male sexual organs.

In the late 1980s, after yellowtail with deformed backbones began appearing, TBT-laced antifouling agents came under suspicion as a potential cause of the abnormality. While researchers could not form a consensus that TBT was to blame, the Fisheries Agency issued a notice in 1990 banning its use at fishing farms.

Kazuo Yachiku, a former veterinarian from Gifu Prefecture who has been researching TBT-linked abnormalities, said the move was prudent.

"The government should conduct thorough research to see whether or not it was used in other fishing grounds," he said.