Collection and sampling of adult salmonids at Lower Granite Dam is an integral part of many studies.  Past operation of the adult trap has been conducted primarily by NOAA Fisheries staff, in cooperation with other agencies.  The demands on use of the Lower Granite Dam adult trap have increased in recent years, and are expected to increase.  Current uses of the adult trap include fall Chinook broodstock collection, run-reconstruction sampling, sampling of PIT-tagged fish from transportation studies to determine life history type (reservoir or oceantype migrant) for fish with known passage histories (i.e, transported, bypassed as a subyearling, bypassed as a yearling, or never detected), radio telemetry studies (both tagging and tag removal at the adult trap), and PIT tagging of wild adult steelhead and wild adult Chinook to assess the efficacy of using of using genetic stock identification (GSI) and PIT tags to estimate the population characteristics of naturally produced steelhead and Chinook salmon.  Operation of the Lower Granite Dam adult trap will provide significant biological benefits for the Snake River fall Chinook ESU, and continued operation of the trap is a proposed action in the federal Action Agencies' 2004 Final Updated Proposed Action and an offsite artificial propagation measure in NOAA Fisheries 2004 Remand Biological Opinion on operation of the FCRPS.