The latest scientific report on sea lice off the British Columbia coast says an infestation near Campbell River fish farms has spread beyond pink and chum salmon to juvenile sockeye and herring.

The study, published online in the North American Journal of Fisheries Management, said the spread of lice will have devastating implications for these other marine species.

A young pink salmon infected with sea lice.
(Courtesy of Alexandra Morton/Science)

Researcher Alexandra Morton said the results were discovered during testing of 47,000 young wild salmon in 2005 and 2006.

When initial results showed lice infestations among sockeye and herring, Morton checked live fish populations, she said.

Older herring are prone to lice but this is the first documentation of lice on herring that have not yet formed scales, leaving the juveniles highly vulnerable, said Morton.

The sockeye in the study were not specifically identified as species from the Fraser River, but fish from those runs pass through the same waters, said Morton.

The study suggests lice may be able to account for last year's low sockeye returns on the Fraser River, she said.

Sea lice are small parasites that attach themselves to various marine animals. Two species are known to attach themselves to salmon.

They are known to affect farmed salmon populations and various studies in recent years have linked them to a decline in wild salmon populations.