Klamath River Fisheries Assessment Program. Juvenile Salmonid Monitoring on theTrininty and Klamath Rivers. Annual Report, FY 1991

摘要

This report marks the fourth year of juvenile salmonid outmigration monitor onthe mainstem Klamath and Trinity rivers, and the third year of monitoring utilizing rotary screw traps. CCFRO initiated the use of rotary traps in the Klamath Basin in 1989. Trapping in 1991 at the Klamath River site near Orleans, CA began in March continued into December utilizing a single rotary trap. A single trap was also utilized at the Trinity River site near Willow Creek, CA and was operating from February into November, The trapping season was divided into 'spring' and 'fall' trapping periods which coincide with hatchery chinook release strategies and corresponding outmigration peaks. Until recently, most fishery investigations in the Basin have been focused primarily on adult returns, due to the concerns regarding harvest allocation and escapement goals. The monitoring of outmigrating juvenile salmonid populations focuses more on the effects of habitat availability and suitability on production success and permits examination of the success of the restoration efforts. The assessment of juvenile production also excludes the little understood variable existing in the ocean environment. Intermittent juvenile salmonid investigations have been conducted in the Klamath River Basin by Coastal California Fishery Resource Office (CCFRO) since 1981 (USFWS, 1981, 1982). In 1988, a substantial monitoring effort was undertaken in both the mainstem Klamath and Trinity rivers utilizing fyke nets, and in 1989, the use of rotary screw traps was initiated at both locations.