Fraser River sockeye salmon: data synthesis and cumulative impacts

preliminary assessment of potential effects (exposure levels and potential adverse effects) toidentify contaminants of concern to guide a more detailed assessment.It was understood in advance that it would be difficult to address potential effects of emergingcontaminants like endocrine disruptors, so the study used qualitative evaluation to take a focusedlook at these substances. The study also set out to identify uncertainties and key data gaps, beforepresenting conclusions and recommendations.Fifteen areas of potential exposure within the Fraser watershed were identified by mapping thespawning, rearing and migration habitats of Fraser sockeye CUs. It was also necessary to identifykey exposure times during spawning and incubation, juvenile rearing, outmigration and adultupstream migration. Given the variable timing among different stocks, the analysis wassimplified by using average timing for each of these four life stages, based on information fromthe literature.Aquatic contaminants inventory: Information from published sources and GIS databases wereused to identify land and water uses (e.g. pulp mills) with the potential to affect water quality andthe intensity of each activity in each of the 15 areas of interest. Contaminants associated witheach activity were derived from the literature and this information was then integrated to identifycontaminants that might be present for each watershed. This resulted in a lengthy list (29 groupsof contaminants) though only a few of these have usable data.The preliminary assessment of effects involved compiling and evaluating exposure data (theprovincial environmental review process has now been merged with Environment Canada – thereis other data, but it probably won’t be available in time). Next steps include selecting toxicityscreening values, calculating hazard quotients, and then identifying contaminants of concern.A map of the Fraser basin showed the limited areas for which routine water quality data isavailable. There is no data for many streams and rearing lakes. When this information is overlaidwith the locations where sockeye could potentially encounter contaminants within the Fraserbasin, it shows that there is no data for most of the 29 contaminant groups that could beencountered in the four freshwater life stages.Toxicity screening and threshold values were established to identify which of the contaminantsin the inventory were preliminary contaminants of concern that could be expected to haveadverse effects on Fraser sockeye.The evaluation of hazards relied primarily on water quality data, along with sediment qualityconditions and tissue residues where such data was available. These data were separated into twoperiods (pre- and post-1990), marking overall positive and negative productivity for most Frasersockeye stocks. Analysis of maximum hazard quotients for the preliminary list of contaminantsof concern, broken down by stock and life history phase, showed that many either declined orchanged very little in the post-1990 period. A water quality index that combines the frequency ofevents exceeding water quality guidelines, along with magnitude and other factors, shows noclear pattern for the pre- and post-1990 period for the spawning or rearing phases, though therewere possibly some increases for the in and out migration phases.Overall, it’s hard to see a strong pattern suggesting water quality has degraded. Further analysisof productivity vs. water quality index revealed no relationship between the two, where data, forany of the four freshwater life history phases. This analysis was done for Fraser sockeye overalland for several specific stocks.45