Fraser River sockeye salmon: data synthesis and cumulative impacts

government documents and interviews with DFO fish health specialists. Results found fewdocumented outbreaks of disease in BC sockeye salmon. Limited survey data do not suggestrecent increases in infectious disease.Most research has been performed on hatchery fish. For wild fish, some research has beenperformed in freshwater but there is minimal information on marine stages. In agreement withthe PSC findings, it was noted that some pathogens picked up in freshwater may not causemortality until they reach the marine stage (Peterman et al. 2010). Most of the results agree withthe list of high risk (possible) infections reported by the PSC workshop. However, IHN wasfound in freshwater (fry), a finding different from the PSC report (Peterman et al. 2010).Information gaps occur where diseases affect different life history stages, but most studies haveonly focused on one stage. Factors that may cause potential interactions and cumulative effectsinclude: temperature, intermediate hosts, pollutants and land use practices.A key participant question was how to design a rigorous survey program for examiningpathogens. Other questions pertained to sea lice and the role of fish farms, temperature andpathogen thresholds, and availability of pathogen data at different life stages of the salmon.Potential Effects of ContaminantsDon MacDonald, MacDonald Environmental Sciences, Ltd.The objective of this research is to evaluate the effects of potential contaminants on Fraser Riversockeye salmon. The scope of work includes an inventory of aquatic contaminants in the FraserRiver Basin in relation to sockeye CUs, a comparison of water quality conditions in the FraserRiver Basin to toxicity data for sockeye salmon, an assessment of contaminants encountered byjuvenile and adult sockeye salmon and an evaluation of the extent to which reductions in sockeyeproductivity are related to contaminant conditions. The inventory confirmed that a wide varietyof contaminants have been released into the Fraser River Basin. Elevated levels of conventionalpollutants, nutrients and metals were observed during key life history stages. However, pre-1990and post-1990 comparisons suggest that water quality may be improving in certain areas of theFraser River, particularly the lower Fraser.Data gaps included limited or no data on water chemistry, endocrine disruptors, sediment, andfew fish tissues. Based on the spatial and temporal patterns of both contaminants and sockeyeproductivity, the researchers concluded that existing data do not support the hypothesis thatwater quality and contaminants have contributed to the decline of Fraser River sockeye salmon.However, due to the large data gaps, evidence is insufficient to exclude some effects on sockeyehealth and survival. The PSC report had similar conclusions (Peterman et al. 2010).