The best medicine – Fishfarmer Magazine

The best medicine06 February, 2014 –

A NEW study indicates that the delousing agent diflubenzuron is not damaging to Cod.

‘We are aware that the use of diflubenzuron has increased, and that this substance can be distributed in the environment, so we wanted to study its effects on fish species that we know feed near sea-cages – in this case, cod,’ said NIFES scientist, Bjørn Tore Lunestad.

The study, which was based on cod kept in tanks, showed that diflubenzuron will be absorbed by cod that consume feed containing this agent. The trials also showed that it is gradually excreted, and that after three weeks the concentration of diflubenzuron in the cod was no longer detected.

The scientists gave the cod a standard treatment consisting of a daily dose of 3 mg active agent per kilo body weight for 14 days, which is similar to the recommended treatment of salmon with diflubenzuron in aquaculture.

Diflubenzuron inhibits the formation of the hard protective shell of the salmon louse, which is the most challenging parasite of farmed salmon. Diflubenzuron is often regarded as an environmental problem, because it can also have similar effects on the shells of other crustaceans that occupy the water around fish farms.