Returns (total run size: escapement + harvest) of adult Chinook and Sockeye salmon to the Kenai River and a major tributary, the Russian River (ADFG data). Returns are plotted separately for populations or “runs” of each species that differ in spawning habitat and timing. The early runs of each species spawn in tributaries not influenced by lakes or glaciers (N). The late runs spawn predominantly in tributaries influenced by lakes (L) or in the mainstem influenced by glaciers and lakes (G + L). Returns have varied by roughly an order of magnitude (7- to 13-fold) over the period of record for all five runs (note the log-scaled y-axis).
For more information, please see the following journal article: Schoen et al. 2017. Fisheries. “Future of Pacific Salmon in the Face of Environmental Change: Lessons from One of the World’s Remaining Productive Salmon Regions.”