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NW Fishletter #294, September 22, 2011

[5] No Smoking Gun For Sockeye: Inquiry Into 2009 Fraser Run Failure Nearly Finished

While a Canadian government inquiry into the 2009 sockeye debacle is drawing to a close, this year's Fraser sockeye run has beat the preseason median forecast by about 50 percent, and it's now pegged at 4.59 million fish, according to the latest word from the Pacific Salmon Commission.

That's not as shocking as last year's 30-million fish return (three times the median prediction), but it still seems to indicate that whatever was responsible for decimating the 2007 outmigration did not have much effect over the next two years. The 2009 return from the 2007 outmigration was only a little over a million fish, when ten times as many were expected.

Judging by this year's sockeye return, migrating conditions for juveniles were still fairly good when they went to sea in 2009. The PSC said the 2011 inseason abundance was below average for the 2011 cycle (5.3 million), but "it represents a significant increase relative to the brood year abundance of only 1,521,000." About 1.6 million have been harvested.

The commission stuck with its pink forecast of 17.5 million, the same as its preseason estimate, and one that reflects average abundance since 2001. About 6.6 million pinks have been caught. Questions have been raised over possible effects of competition for food between young sockeye and pinks when pink runs are larger--which occurs in odd-numbered years in B.C. and Washington waters.

Meanwhile, the Cohen Commission, led by a retired justice from the B.C. supreme court, is still looking into the probable causes of the 2009 sockeye decline. It heard from more witnesses in August and September, part of a process that has been reviewing technical reports on just about anything that might have played a role in the 2009 decline.

But progress has been slow. In January, the Canadian government granted the commission an extension and gave it another $11 million ($25 million total) to come up with a final report by June 30, 2012.

The commission has received reports on diseases and parasites; hatchery diseases; river contaminants; freshwater and marine ecology; salmon farms; fisheries management; predators; climate change; sockeye production dynamics; and lower Fraser habitat use.

Even some U.S. researchers have played a part in the investigation. Consultant Jack Rensel, from Arlington Wash., who has spent many years working with private aquaculture companies, testified about the possibility that blooms of Heterosigma algae in Georgia Strait in 2007 could have played a role in the decline. He co-authored a peer-reviewed article on the subject in 2010.

Rensel told NW Fishletter that the sockeye decline was probably caused by a variety of factors that added up to a major hit on the smolt outmigration.

In his Cohen Commission affidavit, Rensel said he agreed with DFO researcher Dick Beamish, "that the 2007 out-migrant juvenile sockeye met with poor food supply not only in the Strait of Georgia but also further north in Queen Charlotte Strait. He [Beamish] also told me that food web conditions were bad further north in the Gulf of Alaska. So the fish had a series of hurdles that year. My co-authors and I do not maintain that Heterosigma-caused acute or chronic mortality is the only probable source of mortality for these fish, but that it could have been a significant, if not most significant factor particularly in 2007 when the timing of the blooms was earlier than ever before and coincided with the peak out of river migration of Chilko sockeye smolts."

That was also pretty much the take-home message from a report completed by ESSA Technologies that synthesized most of the technical reports commissioned by the inquiry. ESSA president David Marmorek, told the commission earlier this week that most of the evidence pointed to problems that smolts encountered in the early salt water phase of their migration.

Marmorek and ESSA facilitated the contentious PATH process that examined possible causes behind fish declines in the Columbia and Snake basins in the late 1990s. At the time, an independent panel that examined PATH results felt there was little evidence of periodic cycles in the ocean affecting productivity. Since then, most biologists agree that ocean conditions play a major role in overall salmon survival.

According to the latest report, "Based on plausible mechanisms, exposure, consistency with observed sockeye productivity changes, and other evidence, marine conditions and climate change are considered likely contributors to the long-term decline of Fraser River sockeye salmon. It is also very likely that poor marine conditions during the coastal migration life stage in 2007 contributed to the poor returns observed in 2009. Marine conditions were much better in 2008 (much cooler temperatures), which benefited returns in 2010."

The ESSA report had not yet included information on aquaculture, but planned on adding it later.

In recent weeks, the commission heard from both supporters and critics of the farmed salmon industry, and the debate has been covered by the popular media. Critics say the aquaculture pens in the path of the migrating sockeye are vectors for pathogens that can be picked up by wild fish. Supporters say there is no real evidence that this is occurring.

Two recent technical papers on the potential effects of the salmon farms on the sockeye were commissioned by the Cohen inquiry. One by Donald Noakes, a professor of mathematics and statistics at Thompson Rivers University, and long-time DFO collaborator, found no significant correlation between farmed salmon production and Fraser sockeye returns, and no threat of harm from escaped Atlantic salmon, sea lice or disease emanating from fish farms.

The other report, by Lawrence Dill of Simon Fraser University, reported "the greater the farm production, the lower the survival of the sockeye," however, the data time-series of overlapping wild and farmed populations was too short to determine whether the farms were an "important driver" in the Fraser decline. "But it must be equally understood that at this stage of our knowledge," Dill's report said, "it is not possible to say they are not implicated."

Another scientist, DFO researcher Kristy Miller, who testified before the commission in July, suggested that DNA analysis of the sockeye showed that they may have been subjected to a yet unknown virus before they reached the ocean that could have increased later mortality.

But the ESSA report said the information was too skimpy to come to any conclusions about a virus. "While temperature changes or other factors may have resulted in changes in the abundance of pathogens in spawning and rearing habitats, or sockeye susceptibility to such pathogens, the data are insufficient to perform any systematic assessment of these hypotheses. Miller et al. (2010, presentation at June 2010 PSC Workshop) found that sockeye smolts contained a genomic signal indicative of physiological stress prior to entering the ocean, which she attributed to stress in freshwater. However, the genomic signal detected by Miller et al. was present in smolts during both 2007 and 2008 (Miller, handout provided to June 2010 PSC Workshop), yet those years of entry apparently had very different marine survival rates (based on the very large difference in observed vs. expected adult returns in 2009 vs. 2010)."

Consultant Rensel's affidavit also pointed out that the algae bloom might have more far-reaching consequences. "I discussed this with Dr. Miller-Saunders when she cold-called me prior to our paper being published and prior to the PSC [Pacific Salmon Commission] meeting in Nanaimo. At that time she suggested that exposure to Heterosigma may have been the cause of the genomic effects she was seeing in the fish. She had not proposed the virus theory at that time. I spoke with her briefly at the Nanaimo meeting but by then the focus was the theoretical virus. Disease effects in fish are often caused or amplified by multiple stressors, so Dr. Miller-Saunders' findings could reflect a secondary infection, related to exposure to HABs [Harmful Algae Blooms], as has been shown for bacterial diseases of fish after non-lethal HAB exposure."

So far, the results from the Cohen inquiry mirror some of the conclusions reached after a June 2010 workshop on the 2009 decline, sponsored by the Pacific Salmon Commission, that found "physical and biological conditions inside the Strait of Georgia during the juvenile life stage are very likely the major cause of poor survival on the cohort that returned in 2009. Those conditions in the Strait are also likely the major cause of the long-term decrease in productivity of most Fraser sockeye stocks that has occurred since the late 1980s or early 1990s." They judged that similar conditions beyond the Strait of Georgia also affected survival, but to a lesser degree. -B. R.

The following links were mentioned in this story:

Cohen Commission

NW Fishletter 289

NW Fishletter 288

NW Fishletter 68

NW Fishletter 284

Fraser Sockeye Decline June 2010 Workshop

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