Beginning in the mid 1980s and through much of the 1990s, production of the Crescent River sockeye (Oncorhynchus nerka) salmon declined as evidence by lower adult returns and fewer adult recruits produced per spawner (RPS). For brood years 1984-1988 and 1990, RPS values fell below replacement. Concern over the decline in productivity initiated limnological studies in 1996 to determine whether sockeye salmon production was related to variability in changing conditions of the major nursery lake (Crescent Lake) of this system. The escapment goal range was lowered in 1998 from 50,000-100,000 to the current 25,000-50,000 range in part based on the low density of cyclopoid (Cyclops scutifer) copepods, the primary food resource (zooplanktion) [...]
