BC's Sea Lice Problem


Photo: Alexandra Morton

Sea lice from salmon farms are one of the most significant threats facing wild salmon in British Columbia. Although sea lice occur naturally, lice infestations have only recently put wild salmon populations at risk. In the spring, fish eggs hatch and juvenile salmon emerge from the rivers and make their way to the ocean estuaries and bays. It is primarily when young salmon fry migrate past salmon farms that they encounter large concentrations of sea lice. When these large concentrations of lice attach themselves to juveniles, their bodies may not be able to cope, and they may die.

Stocking hundreds of thousands of fish in small areas (net-pens) makes fish farms ideal and unnatural breeding grounds for lice. This significantly increases the number of lice in surrounding waters and the threat to out-migrating wild juvenile salmon.

* Farmed fish make great hosts for sea lice because they are confined and in high densities.
* 91% of BC’s farmed salmon are the non-native Atlantic species, which are more susceptible to sea lice than many other salmon species1
* Research experiments have shown that pink and chum salmon fry can die when infected with only a single mature sea louse, and data suggests that up to 95% of migrating juvenile salmon can be infected2.
* Current chemical treatment of sea lice on farms may be harmful to other marine species and may not reduce lice levels enough to protect wild salmon