Tuesday, August 30, 2011
Aquaculture's Connection with Wild Salmon Declines Becoming Clearer
The veil of secrecy which has long shrouded the salmon farming industry in BC has begun to lift, and while there is still much to learn the story that is unfolding is providing vindication for the concerns of wild salmon advocates, who have long argued that salmon farms are responsible for declining salmon populations Southern British Columbia. Last winter BC Ministry of Environment scientist Gary Marty published a controversial paper, using never before released sea lice data from salmon farms in the Broughton Archipelago. The paper established a connection between sea lice abundance in fish farms and their loading on wild juveniles, but concluded that salmon farms were not responsible for the collapse in pink salmon stocks observed in the Broughton. More disconcerting Marty stated emphatically that management actions such as closed containment and fallowing were unnecessary. However a paper published by Marty Krkosek and a group of colleagues in the latest issue of the Proceedings of the Nation Academy of Sciences (PNAS) came to a very different conclusion. Saying Marty's findings,
"are based on a statistically nonsignificant result of a correlation test between pink salmon spawner–recruit data and L. salmonis abundance on salmon farms in the Broughton Archipelago."
Using the newly available sea lice data published with Marty's work, Krkosek's group used a more robust modelling framework to confirm their previous conclusion that sea lice from salmon farms pose a serious threat to wild pink and coho salmon. They conclude that mortality from sea lice has depressed wild populations and in some years upwards of of 88% of pink and 92% of coho mortality was attributable to sea lice.
Then yesterday at the Cohen commission wild fish advocates made a major breakthrough. After years of demanding that salmon farm disease records be released the BC government at last made disease records public. While the records represent a limited number of samples they suggest that Salmon Leukemia, the disease associated with high mortality in Fraser Sockeye is present on fish farms in the Georgia Basin. Perhaps more frightening though, hundreds of cases of Infectious Salmon Anemia (ISA) have been observed over the last several years, all the while the farming industry and government insisting that ISA was not present in British Columbia.
Read the latest post on Alexandra Morton's blog for more information
The light of public scrutiny is finally starting to shine on the reality of salmon aquaculture in British Columbia and not surprisingly what we're seeing isn't pretty. Now we're left to hope that the public will demand more accountability out of their government and the corporations who do business in BC. Otherwise the future looks bleak for Fraser Sockeye and other Georgia Basin salmonids.