Abundance of the chinook salmon escapement on the Chickamin River, 1995

Description

The abundance of large chinook salmon Oncorhynchus tshawytscha that returned to spawn in the Chickamin River in 1995 was estimated using a mark-recapture experiment. Age, sex, and length compositions were estimated for the immigration. Set gillnets were used to capture 112 immigrant chinook salmon 660 mm in (mid-eye to fork) length during June, July, and August 1995; 109 fish were marked with spaghetti tags and opercle punches. During August, 167 chinook salmon 660 mm long were captured at spawning sites and inspected for tags; 7 of these fish had been previously marked. A modified Petersen model (n1 = 109, n2 = 167, m2 = 7) estimated that 2,309 (SE = 723) chinook salmon 660 mm in length immigrated to the Chickamin River in 1995. Peak survey counts in August totaled 356 large chinook, about 15% of the estimated inriver run. From immigrant age and length composition data collected in gillnet and spawning ground samples, it was estimated that 1.8% of the gillnet catch was age -1.1, 20.2% was age -1.2, 37.6% age -1.3, 35.8% age -1.4, and 1.8% age -1.5 (72 males and 63 females) and that 7.3% of the spawning ground samples were age -1.2, 24.4% age -1.3, 66.7% age -1.4, and 1.6% age -1.5 (76 males and 92 females).

Subjects

Series Statement

• Fishery data series -- no.96-37.

Links

• URL