Estimated Cedar River Sockeye Salmon Egg to Migrant Survival Rate


Sockeye eggs and alevins (larval fish) incubate in the gravels of the Cedar River during the fall, winter and spring. As the young fish emerge from their redds (gravel nests) in the spring, nearly all move directly downstream into Lake Washington where they typically rear for about one year before migrating to sea. The rate at which incubating sockeye survive is one measure of general incubation conditions in the river. Incubation survival, measured here as "egg to migrant survival", can vary widely from year to year. One of the major factors affecting survival appears to be the magnitude of flood events in any given year. Large floods can scour eggs and alevins out of the gravel resulting in relatively high mortality rates.


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