Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 4301
Title: Variation in the early marine survival and behavior of natural and hatchery-reared Hood Canal steelhead
Author: M. E. Moore, B. A. Berejikian, E. P. Tezak
Publication Year: 2012
Journal: PLoS ONE
Keywords: steelhead
Abstract:

Domestication selection and direct effects of the culture environment can both cause captively-bred fish populations to survive at low rates and behave unnaturally in the wild. New conservation hatchery approaches to fish rearing seek to reduce domestication and maintain genetic resources within depressed fish populations. This study used acoustic telemetry to compare three years of early marine survival estimates for two wild steelhead populations to survival of two populations raised at two different conservation hatcheries located within the Hood Canal watershed. Steelhead smolts from one conservation hatchery survived at rates (freshwater: 88.9%, early marine: 27.4%) similar to the two wild populations (freshwater: 88.9-97.7%, early marine: 5.7-14.7%), while smolts from the other conservation hatchery exhibited reduced freshwater and early marine survival (freshwater: 43.1-60.2%, early marine: 1.9-7.4%). Freshwater and saltwater travel rates did not differ significantly between wild and hatchery individuals from the same stock, though hatchery smolts did display reduced migration ranges within Hood Canal. Between-hatchery differences in rearing density and vessel geometry likely affected survival and behavior after release and contributed to greater variation between hatcheries than between wild populations. Our results suggest that hatchery-reared smolts can achieve early marine survival rates similar to wild smolt survival rates, and that migration performance of hatchery-reared steelhead can vary substantially depending on the environmental conditions and practices employed during captivity.

Description:

This research compares the early marine survival estimates and migration behavior of wild steelhead smolts to survival and behavior of hatchery fish raised for conservation purposes. We conclude that hatchery fish are capable of surviving at rates similar to wild fish, and that conditions within a hatchery likely affect the success of migrating steelhead.

Foci: Maximize effectiveness and minimize impacts of artificial propagation in recovery, rebuilding and stock sustainability