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Much More To Sea Lice Debate

CANADA - The number of sea lice in the natural environment is affected by the salinity of the ocean. There is a genetic difference between sea lice in the Pacific Ocean and the Atlantic Ocean. Wild salmon in British Columbia (BC) have a natural ability to shed sea lice once the fish have reached a certain size.

These are all important points proven in the expansive body of sea lice research that need to be considered when reviewing the latest paper from anti-salmon farm campaigner Alexandra Morton, Michael Price and John Reynolds.

The study, titled "Evidence of farm-induced parasite infestations on wild juvenile salmon in multiple regions of coast British Columbia, Canada," not surprisingly given the author's backgrounds, concludes that salmon farms are a major source of sea lice on wild salmon and suggests in its introduction that this could be a cause for stock collapse.

The trouble is that their overly-simplistic analysis has significant gaps, reuses questionable methodology and is based on flawed assumptions. For example, the 'control site' - the area with no farms where they collect samples to compare with fish from near farms - has significantly lower salinity levels than the other locations. Since sea lice levels are naturally lower where salinity is reduced, this makes it a poor comparison.

There's more too about the natural environment that needs to be considered when researching sea lice - ocean currents, geography, natural population variations are all on that list.

The reality is that salmon in these areas seem to be doing quite well. There were notably -high returns of Pink salmon to the Broughton Archipelago in 2005 and 2009, and in 2008, the Department of Fisheries and Oceans sampled nearly 4000 Pink salmon and didn't find a single one at risk for lethal harm from sea lice. That's important, because we know that the only Pacific salmon at risk from sea lice is the Pink at very early stages of life when it's still too small to shed lice on its own.

This paper actually shows some real successes in farm management. It reports that sea lice intensity numbers throughout the study are very close or below the suggested conservation threshold recommended by the BC Pacific Salmon Forum report - developed over years of study and with five million dollars invested in research.

As one industry staffer (a registered professional biologist) said, a major weakness of this type of study is that it is done in isolation of other sea lice researchers. Salmon farmers are collaborating with researchers and regulators to investigate and address sea lice concerns. Together we're coming up with sound knowledge and solutions.

Our industry is well managed and highly regulated. Sea lice management programs have been proven effective - and our farmers are opening the doors to information, with the two largest producers - Marine Harvest Canada and Mainstream Canada - posting site-by-site sea lice data online.

We're proving that sound science leads to effective policy and sustainable industry. Studies like this one have to be read critically with that in perspective.

the Fish Site Editor

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