The estimated feeding grounds for stocks with spawning grounds south of
the Aleutian Islands were all located in the NE Pacific itself but with
little overlap between the stocks (Figure 4). The SE Alaska stocks
Chilkat and Chilkoot, which have spawning grounds 10 km away from each
other, showed well separated at-sea locations, with Chilkoot being
distributed 10 degrees further west than Chilkat. While Columbia River
stocks have the most southerly spawning grounds, their high seas
distributions were located in the northern sector of the NE Pacific. The
Rivers Inlet stock was distributed further south than any other stock.
With the exception of Rivers Inlet, all stocks were sampled yearly and
produced significant correlations with highest significance usually
found using the original time series (Table 2, correlation coefficients
were usually higher with smoothed time series but the adjusted degrees
of freedom reduced the
Figure 4. Estimated feeding grounds during the last year at sea of (a)
Red lake, (b) Upper station, (c) Chilkoot, (d) Chilkat, (e) Okanagan,
(f) Wenachee and (g) Rivers inlet sockeye salmon stocks (Gulf of
Alaska). Strongest correlation coefficient between SST and
δ13C value is indicated by a white cross. Locations of
the point of entry in the freshwater system of the different stocks is
shown (red circle).
significance, see Methods). Bristol Bay stocks at-sea distributions
showed interesting patterns with some stocks being distributed in the
Bering Sea and some others along the Aleutian Islands (Figure 5).