Critics of salmon farming are quick to point to the disastrous development of the Pacific cod fishery on the East Coast of Canada years ago as an example of mismanagement of fish stocks by Fisheries and Oceans Canada (DFO). But the fact remains that it was the politicians of the day that kept bowing under pressure from fishermen to keep catching cod, despite warnings from DFO scientists that the situation was heading for disaster. Now the same scientific body is coming out with the truth about salmon farming and sea lice in British Columbia, and it is now the critics of the industry that are trying to convince the population that the situation is quite different.
In a section on its web site, DFO provides someFacts About Sea Licethat should be mandatory reading for journalists, politicians and the public individuals and organizations interested in the subject. In the form of a Question and Answer session, DFO addresses a number of related issues- here are a couple of the most interesting Facts;
Is it true that DFO research supports claims that sea lice from salmon farms is broadly infecting and harming wild Pink salmon stocks in the Broughton Archipelago?
No, this is not true. In fact, DFO scientists at the Pacific Biological Station have conducted laboratory research on the impact of sea lice on juvenile pink salmon from the Quinsam and Glendale rivers. Juvenile pink salmon were studied in three size categories (0.3 gm, 0.7 gm and 2.4 gm) and exposed to high, medium and low intensities of sea lice to study rates of infection and its effect.This 2008 study by DFO scientists indicated that, in a controlled laboratory setting, deliberate exposure to high concentrations of sea lice can contribute to some mortality of very small juvenile wild pink salmon, that is, lighter than 0.3 grams. No mortality was observed in larger fish exposed to sea lice in this study (0.7 or 2.4 grams). Pink salmon in the wild are approximately 0.3 gm when they initially enter the marine environment, as demonstrated by sampling in the BA since 2003. The larger size categories of juvenile pink salmon are consistent with past research conducted in this DFO laboratory. This laboratory study is the first time that a DFO has found a direct link between sea lice infection and juvenile salmon mortality.Laboratory observations that sea lice can lead to some mortality on small pink salmon are consistent with many statements from NGOs and other researchers. It is important to note that many other sources of mortality could be involved in the natural environment, predation by other species, ocean climate, and habitat loss. It is also possible that other wild fish species may be a source of sea lice infecting juvenile pink salmon.DFO is currently examining its extensive information on the distribution of juvenile pink and chum salmon from field studies to determine where they are and their proximity to salmon farms in the BA.Is it true that sea lice are killing juvenile Sockeye salmon?No. Sea lice from salmon farms cannot singularly explain the extremely poor marine survival of Fraser River sockeye. Sockeye returns to the Skeena River in northern British Columbia were also significantly lower than anticipated this year and the migration route of juvenile sockeye from this river system does not take them anywhere near fish farms.We also know that the majority of sea lice found on juvenile sockeye in the Strait of Georgia where the Fraser River salmon migrate are not the same sea lice species reported on BC salmon farms. (The most commonly found species of lice on farmed Atlantic salmon is Lepeophtheirus salmonis, while sockeye juveniles were found to harbour Caligus species- Ed. Comment) Juvenile sockeye that migrate past salmon farms in the Discovery Islands are significantly larger than pink salmon – 5 to 10 grams in size - when they migrate into the ocean, well beyond the threshold for susceptibility to sea lice.Since 2003, DFO has conducted sea lice studies, contributing to a growing body of scientific knowledge. Canada is recognized internationally as a world-leader on sea lice research, with a research and management approach informed by previous and current levels of international scientific knowledge and on-the-farm practices.
