Cohen Science Workshop


Cohen Report

To view the Cohen report as archived by Library and Archives Canada, please click the link below. Note: information may be out of date and some functionality lost.

Cohen Science Workshop

In place of the Visions Conference that FRAFS normally sponsors every year, in 2012/2013 the FRAFS Executive Committee decided to organize a workshop to discuss the scientific investigations of the Cohen Inquiry into the decline of Fraser River sockeye salmon, which concluded in October 2012. The workshop was facilitated by Dr. Dave Levy, former Science Director at the Commission, and included presentations from a number of scientists who provided key evidence for the Inquiry. Following the presentations, a Panel consisting of Gord Sterritt, Howie Wright, Ken Malloway and Brenda Gaertner was convened to provide their perspectives on the Cohen science results.

Scientific papers commissioned by the Cohen Inquiry have been published as 15 Technical Reports.

Arguably one of the most important discoveries of the Commission resulted from the work of Randall Peterman and Brigitte Dorner of Simon Fraser University, who demonstrated that sockeye productivity declines are by no means unique to the Fraser Watershed and are part of a regional pattern extending from Washington State through to SE Alaska. A majority of BC sockeye populations, including those in Barclay Sound, Rivers Inlet, the Skeena and the Nass show similar declines. This finding requires that the mechanism for declining sockeye productivity would likely be found in a shared habitat, either the coastal or offshore marine environment. Skip McKinnell of the North Pacific Marine Sciences Organization presented evidence that it is the early marine life cycle when post-smolts are migrating towards the continental shelf of Alaska when most mortality takes place.

Justice Cohen heard conflicting evidence about Salmon Farm impacts from Larry Dill, Don Noakes, Brendan Connors and Josh Korman and was unable to draw strong conclusions. In recognition of the potential importance of and uncertainties around disease transfer to sockeye post smolts, he recommended a farm management system in the Discovery Island area that would require operators to demonstrate that their operations are low risk, otherwise the farms should be removed from the sockeye post-smolt migratory pathway by 2020.

Cumulative impacts as well as impacts specific to the freshwater environment were addressed by Dave Marmorek who concluded that marine factors and climate change were responsible for the declines. Villy Christensen reported on fish, bird and mammal predation as causal factors in the decline, but was hampered in his analysis by insufficient evidence to draw firm conclusions.

The overall conclusion in the Cohen Report in regard to the long-term decline is summarized in the following statement:

“Some, I suspect, hoped that our work would find the “smoking gun” – a single cause that explained the two-decade decline in productivity. The idea that a single event or stressor is responsible for the 1992–2009 decline in Fraser River sockeye is appealing but improbable.”

The Cohen Report recommends a number of research investigations be carried out to address key uncertainties including:
• Mortality during downstream migration
• Marine mortality
• Harrison River sockeye
• Regional production dynamics
• Cumulative effects

At the conclusion of the Workshop the facilitator presented his view that the two most relevant benchmarks for the future success of the Cohen Commission are: 1) the degree of Implementation of the 75 recommendations, and 2) the future sustainability of Fraser River sockeye salmon and the Fraser sockeye fishery.

Click the links below to view or download the presentations in PDF format.

Christensen/Trites: Marine and Freshwater Predators
Dill: Role of Aquaculture in the Decline
Levy: Intro, Role of Science, and Recommendations (Part 1)
Levy: Intro, Role of Science, and Recommendations (Part 2)
Marmorek: Cumulative Impacts
Marmorek/Nelitz: Sockeye and Freshwater Ecology
McKinnell: Sockeye and Marine Ecology
Peterman/Dorner: Production Dynamics of Fraser Sockeye