These substances prevent the formation of chitin and so when used on lice, it leads to the death of the parasite upon first moulting after treatment.
Tests that have been made by various research institutions show that these substances may be present in sea floor sediment for prolonged time. The active substances can be detected in high concentrations more than seven months after a single treatment of farmed fish.
The Fisheries Directorate will consider measures to limit the use, focusing on how repeated or heavy use can be avoided.
The Directorate will also strengthen the monitoring of such environmental effects and will therefore propose to the Ministry of Fisheries and Coastal Affairs that it require collection of samples from localities that have treated fish, particularly where there is a risk of accumulation of drugs and chemicals.
Concern Over the Environmental Impact of Sea Lice Agents
NORWAY - Concern is rising over the use of diflu and teflubenzuron as sea lice agents and the environmental consequences it may be having.
by Lucy Towers
