Fraser River sockeye salmon: data synthesis and cumulative impacts

and biological variables. The combined rank for all variables in each year showed 2008 as thebest year in terms of marine conditions for salmon and 2005 was the worst year. Since 1998, theaggregate index is significantly correlated with Chinook and Coho returns to Bonneville Dam.Mackas Ecosystem Productivity Index: Dave Mackas (DFO) has also developed an ecosystemproductivity index for SW Vancouver Island. His index showed a period of warm, unproductiveconditions starting in 1992. The summer of 1992 was noteworthy for the return of sardines to BCafter a 47 year absence. The warm and unproductive period continued through the 1997/98 ElNino. A few years around 2000 were better for coho survival on the west coast but not for Frasersockeye. Indeed, the 2007 ocean entry year tended to cold and productive rather than warm andunproductive. The mismatch between the MEPI and Fraser R. sockeye salmon survival from1999-2002 may have arisen from differing locations of MEPI data and sockeye migration routes.As with Peterson’s index from the coast of Oregon, the MEPI shows that 2008 was the mostextreme of the years of cold and productive.Fulton and LeBrasseur’s work in the 1980s indicated that the BC coast is in a transitionbetween two major marine zones. In El Nino years, the west coast of Vancouver Island isdominated by southern/offshore subtropical copepods instead of the lipid-rich subarcticzooplankton that form the basis of an enriched food web where salmon seem to prosper. Andsince 1992, there have been far more unproductive than productive years.In defining the nature of the decline in Fraser River sockeye salmon productivity, it’s importantto get the pattern right because you would look for different causes if you think it’s a shift vs. atrend.DiscussionReynolds: Neither Mackas or Peterson predicted the bad 2009 return.McKinnell: The factors that appear to have affected the 2009 return involved climate, oceanand terrestrial interactions focused on Queen Charlotte Sound – both the Mackas andPeterson indices are based on West Coast indicators. I think the difference is largelybecause a result of where the data for the indicators are derived.Reynolds: It would be useful if there was independent data to actually show that the correlationbroke down that one year.McKinnell: It would be interesting plot MEPI vs. the salinityPeterman: The PSC report suggested that zooplankton production in Queen CharlotteSound/Strait 2007 was not anomalous.McKinnell: Recall that the spring bloom in Queen Charlotte Sound/Strait was the latest in2007 since records began in 1998. There is also a need to consider where the zooplanktonbiomass records came from. Those near Triangle Is. may have been rather normal, butthose in eastern Queen Charlotte Sound may have been quite different.Peterman: Rick Thompson pointed out there was much stronger downwelling along the coast,which would lead to a consistent effect.McKinnell: There have been significant reorganizations of North Pacific climate systemalong the West coast. There was definitely one around 1977 and the next significant51