Vancouver scientists have released a damning report that they say conclusively links the spread of sea lice via farmed salmon to wild salmon.

The findings published in the journal of Britain’s Royal Society shows how one salmon farm on the British Columbia coast caused an explosion of sea lice that spread to young wild salmon migrating past.

The lice then multiplied on the wild fish, which led to a secondary outbreak that spread to other wild salmon up to 30 kilometres away from the farm. Sea lice feed on the flesh and the blood of salmon and in large numbers will weaken and eventually kill the fish.