EPA grants one-year exemption for pesticide to control catfish parasites

Seafood.com
January 17, 2003

The Mississippi Department of Agriculture and Commerce has obtained an emergency exemption from EPA for the use of niclosamide a pesticide used to control the parasite-hosting rams horn snail. The one-year exemption was given after concerns that the parasite (a species of yellow grub trematode) could cause major problems for Delta catfish producers.

This parasite has the potential to cause million of dollars in economic loss if we dont control it. The devastation experienced by the industry could lead to a total economic hardship on our state economy of at least $350 million a year, said Dr. Lester Spell, Mississippi agriculture commissioner.

Its estimated that more than half the states 113,500 acres of catfish ponds are threatened by the parasite.

The parasite uses three pond-loving hosts during its life cycle: pelicans, snails and fish. It reproduces while living in a pelicans gut, and its eggs exit with the birds feces. As pelicans often congregate around catfish ponds, their deposits have easy access their next host, the rams horn snail.

Once inside the snail, the eggs mature into larvae and then leave the snail looking for a fish. After the fish are infected (fingerlings suffer liver and kidney damage due to the parasite) pelicans will eat them and the cycle continues.

By using niclosamide a product manufactured by Bayer AG and commercially known as Bayluscide to control snails and interrupt the parasites life cycle, its hoped the threat to aquaculture will be lessened, Spell said.