Fraser River sockeye salmon: data synthesis and cumulative impacts

survey data, but they were looking for herring, not sockeye. There is disparate informationbut we can put it on a map to show how they use the environment and how that changes andoverlay it with other information and see what associations there are.Routledge: Michael Price’s sampling information may be useful.Marmorek: On Day One, the Kalman filter analysis showed the pattern was at a largergeographic scale, so how likely is it that Lower Fraser habitats are what’s driving the longtermdecline?Johannes: I don’t know. The data don’t show how they stop and start. Some years they barrelthrough and other years they dally around Malaspina and Texada. We couldn’t pull apart thecharacteristics by stock but there may be a tie in between what they hit in Queen CharlotteSound – if they find unfavourable conditions there. In other circumstances, they split alongthe two sides of Georgia Strait and slow down.Pickard: What data indicate the speed at which they travel in Georgia Strait.Johannes: Seine catches (1960s to 2003 catch data), June sampling data for herring and somePOST tagging studies.Pickard: Regarding the northern boundaries, it would seem sensible to include the area with thefish farms.Johannes: I will make clear what information exists and doesn’t exist on habitat use and how itchanges annually.Marmorek: How does this study relate to the fish farm chapter?Levy: This project needs to be clearly separated from #5.Adult river migration and spawning successEn route mortality, pre-spawn mortality and intergenerational effectsScott HinchFactors examined for this study were among-year and among-stock patterns and theirrelationship with spawner abundance and spawning success.Definitions: En route loss is defined as the difference between Mission and spawning groundescapement estimates, after accounting for in-river harvest (it includes unreported catch). Prespawnmortality is the percent unsuccessful egg deposition by female spawners.En route loss can be large relative to harvest and escapement and has been very important inrecent years. Prior to 1992 it was rarely shown, which was partly due to the way the data werecollected. It has been very high in recent years for Early Stuart. Early Summers show the samepattern of increasing en route losses, though the proportions are lower. Late runs show very largeen route losses, starting suddenly after the mid-1990s.DNA analysis can now be used to assign in-river migration mortalities to specific stocks. Nine of12 Fraser sockeye stocks had high en route mortality (over 50%) in most recent years, with theearly and late stocks suffering the worst impacts.61