Pacific salmon are tougher than their Atlantic cousins!

The Daily News came across a study from the Fraser Institute that shows that Pacific Salmon that seems to show that the Pacific species of the fish is less vulnerable and more resistant to sea lice than those frisky little Atlantic interlopers.

The study will serve to add to the debate over the status of fish farms along the west coast and whether they should be allowed to grow or be shut down. It’s a debate that has had the aqua culture industry and fisherman’s unions squaring off over the impact of the farmed salmon industry on the wild stocks.

The paper published the study on the front page of Tuesday’s edition.

PACIFIC SALMON ‘RESISTANT’ TO SEA LICE – STUDY
The Daily news
Tuesday, December 5, 2006
Pages one and two

Pacific salmon may be more resistant to sea lice than their Atlantic counterparts and more research is needed to determine if sea lice found in fish farms are impacting wild salmon, says a new study, released today by The Fraser Institute.

“Large gaps remain in our understanding of the impact of sea lice on Pacific salmon and whether or not fish farms contribute to the problem,” said Dr. Kevin Butterworth, co-author of Sea Lice: The Science Behind the Hype, and a Research Associate at the Centre for Aquaculture and Environmental Research at the University of British Columbia.

“Through our research, we have found that Pacific salmon appear to be less susceptible and more resilient to sea lice than Atlantic salmon. Much of the information available on the impact of sea lice is from Atlantic salmon, not Pacific salmon.”

The international study, co-written with Dr. K. Fiona Cubitt, Dr. Bengt Finstad, Professor Felicity Huntingford, and Dr. R. Scott McKinley, points out that in B.C. waters, 14 different species of sea lice exist, but only two species pose a potential threat to wild and farmed salmon.

Butterworth said the difficulties in distinguishing between sea lice species can contribute significantly to the public perception of the impact of sea lice on both wild and farmed salmon. If these species are not correctly identified, the inferences that fishermen and the general public make about the origin of the sea lice on juvenile Pacific salmon can be incorrect.

The study shows that wild salmon vastly outnumber farmed salmon in BC, with 128 salmon farm tenures in BC, compared to more than 9,600 distinct stocks of wild Pacific salmon. Additionally, over-wintering wild coho and chinook salmon and schools of wild sticklebacks in coastal waters provide ideal, potential hosts upon which the sea lice can over-winter, ready to infect out-migrating wild smolts in the spring.

As a result, there is potentially a larger reservoir of sea lice associated with wild fish than with farmed salmon. This is the opposite of the North Atlantic, where due to the severe depletion of wild fish stocks, it is primarily the salmon farms that contain the largest pool of potential hosts upon which sea lice can over-winter. Researchers also determined that sea lice are native and prevalent in the North Pacific Ocean and are found on 90 per cent of salmon.

“There is no doubt that sea lice transfer from wild salmon to farmed salmon. There are no sea lice on farmed salmon when they are transferred from freshwater hatcheries to the sea farms to be grown through to market size.”

But he points out that many questions remain about the movement of sea lice from farmed salmon in net-pens to wild Pacific salmon, two of which have never been answered by definitively by any study. Namely, whether or not the number of sea lice transferred from farmed salmon to wild Pacific stocks are enough to have an impact; and what is the minimum number of sea lice on an individual salmon required to harm it.

“It remains important that sea lice are monitored on farmed and wild salmon until the relationship is better understood,” said Butterworth.

“But until these questions are answered, we can not conclude that sea lice found in salmon farms are significantly impacting wild Pacific salmon.”