|
Caption: This chart shows estimates of the number of juvenile fish passing the U.S. Fish and Wildlife Service downstream migrant trap at Big Bar from 1991 to 2000. The low number of juvenile Chinook from 1991 to 1993 reflects low escapements of adults the previous years. Juvenile Chinook abundance has varied from 77,230 in 1991 to just fewer than 2,000,000 in 1998, although more than 50% were hatchery fish in the latter year. Because trap efficiencies have been calibrated, annual estimates of the number of juvenile fish passing the trap can be calculated. See the Source Table for comprehensive trap records from 1993 to 2003. See Info Links for more information and a link to USFWS reports.
|