BCSFA calls the analysis overly-simplistic with significant gaps and that it reuses questionable methodology. (Photo: Alexandra Morton)
Study on sea lice affecting wild BC salmon flawed: BCSFA
Friday, November 12, 2010, 16:20 (GMT + 9)
The British Columbia Salmon Farmers Association (BCSFA) has responded to the study linking salmon farms with lice on wild salmon by stating that the amount of lice in the natural environment is affected by the salinity of the ocean. Further, there is a genetic difference between sea lice in the Pacific and the Atlantic Ocean, and BC’s wild salmon can naturally shed the parasites once the former reach a certain size, said BCSFA.
These and other points need to be taken into account when looking at the article in question, the association asserted, which was published in the latest issue of the Canadian Journal of Fisheries and Aquatic Sciences.
Study authors professor John Reynolds from Simon Fraser University, Michael Price at the University of Victoria and Salmon Coast Field Station Director Alexandra Morton determined that salmon farms are the main origin of parasitic sea lice plaguing wild juvenile pink and chum salmon along the BC coast, and that this could be the cause of the stock’s decline.
But BCSFA calls the analysis “overly-simplistic” and claims it has significant gaps, reuses questionable methodology and is founded on flawed assumptions.
For example, the association insisted, the salinity levels in the 'control site' are significantly lower than in the other locations, and because sea lice levels are naturally lower when salinity is reduced, the choice made for a control site is poor. Also, ocean currents, geography, natural population variations and more were not considered.
BCSFA affirmed that salmon in BC seem to be “doing quite well,” noting significantly high returns of pink salmon to the Broughton Archipelago in 2005 and 2009. In 2008, the Department of Fisheries and Oceans (DFO) sampled nearly 4,000 pink salmon and did not find them at lethal risk from sea lice.
That is significant because, the association said, the only Pacific salmon at risk from sea lice is the pink and at very early stages of life, when it cannot shed the lice.
In fact, BCSFA said, the article shows real progress in farm management by reporting that sea lice intensity is very close or below the suggested conservation threshold recommended by the BC Pacific Salmon Forum report.
According to the association, one industry staffer and registered professional biologist said that a key weakness of this type of study is that it is conducted in isolation of other sea lice researchers.
Salmon farmers are working with researchers and regulators to look into and tackle sea lice concerns. Sea lice management schemes have been effective and the two main farmed salmon producers, Marine Harvest Canada and Mainstream Canada, have posted site-by-site sea lice data online, BCSFA said.
- Lice infests wild salmon all along BC coast: study
By Natalia Real