Figure 8. Salmon δ15N plotted against zooplankton
δ15N values. Each point represents an average value
for a sockeye salmon stock that have been assessed to be distributed in
the Gulf of Alaska. Zooplankton δ15N estimates were
obtained from isoscapes presented in Espinasse et al., 2019.
Table 3. Trophic level estimates for nine salmon stocks assessed in this
study to be distributed in the Gulf of Alaska during their last year at
sea. The trophic level is based on the difference between
δ15N values in salmon scales and large herbivorous
copepods (TL 2) analyzed for this region, assuming a trophic level
enrichment factor of 3.4‰.