Growth and Habitat Occupancy of Hatchery Coho Salmon in an Engineered Stream

Abstract We designed and constructed a natural channel (hereafter, engineered stream; length = 284 m, flow rate = 0.08 m3/s) and compared weight, length, and condition factor between hatchery coho salmon Oncorhynchus kisutch (brood years [BYs] 2000 and 2002) reared in the engineered stream and those reared at Dungeness Hatchery, Washington, under similar temperature regimes. In addition, we compared rearing density, egg-to-smolt survival, smolt density, and smolt capacity in the engineered stream with reported reference values for wild coho salmon in rivers. Mean weight and length of fish reared in the engineered stream were 8-32% and 39-154% less, respectively, than those of fish reared in the hatchery. Mean condition factor was 1.6-3.1% greater for fish reared in the engineered stream than for fish reared in the hatchery. Mean monthly growth differed between the engineered stream and hatchery treatment groups; fish in the engineered stream lost weight during the winter, and those in the hatchery gained ...