The Fisheries Agency banned the use of hormone-disrupting TBT in aquaculture in 1990. (Photo: Tor-Eddie Fossbakk/FIS)

Banned hormone-disruptor found in farmed fish

JAPAN
Wednesday, October 07, 2009, 00:50 (GMT + 9)

A fishery cooperative in Owase, Mie Prefecture, found traces of a banned parasite repellent in fish from a regional farm. Almost all shipments of farmed fish have thus been voluntarily halted due to concerns over the hormone-disrupting chemical tributyltine (TBT), known to be harmful to both humans and the environment, the cooperative said on Saturday.

Shipments were suspended on Wednesday and no health complaints have been reported since then. The central government's Fisheries Agency will examine the aquaculture farm in Owase and others throughout the country for the organic tin compound TBT, Kyodo News International reports.

The Fisheries Agency banned the chemical that prevents shellfish and seaweed from fouling nets in 1990.

A cooperative member, according to the Owase fishery cooperative, had a can of the TBT-laced antifoulant located in his home. In January 2008, bags of sawdust infused with the chemical were placed in the water where yellowtail are farmed.

''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 member stated.

The bags have since been removed, but how long they remained in the water is unknown. All antifouling agents are currently being tested for TBT, the cooperative said.

''We have offered the antifoulants currently used by other cooperative members to a laboratory to confirm if they are safe,” affirmed the leader of the cooperative.

Studies have shown that even trace amounts of TBT can cause reproductive abnormalities, such as causing female shellfish to grow male genitals.

Yellowtail were found to have deformed backbones in the late 1980s, and TBT antifouling agents were suspected to be the cause. The Fisheries Agency then banned the substance from aquaculture farms in 1990.
 
''Toxic substances show their effects first in animals before humans,'' said Kazuo Yachiku, a former veterinarian from Gifu Prefecture who has been researching abnormalities associated with TBT.

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

The major fishing town of Owase is located in Mie Prefecture on the Pacific coast. Its annual harvest of farmed sea bream and yellowtail is around 960 tonnes.

By Natalia Real
editorial@fis.com
www.fis.com