Migration behavior and survival of artificially
reconditioned kelt steelhead through the lower Columbia River
Douglas R. Hatch, R. Branstetter, J. Whiteaker, D. Fast, J.
Blodgett, B. Bosch, T. Newsome, and M. Johnston.
A field study was initiated in 2004 to evaluate the
migration of artificially reconditioned kelt steelhead
through the lower Columbia River with hydro
acoustic tags. All natural-origin
steelhead populations originating above Bonneville Dam are listed as threatened
or endangered under the Endangered Species Act.
Post-spawn steelhead (kelts) are numerous in
the Snake, Columbia, and Yakima rivers in the spring. In many years 20% of the upstream steelhead
migration is collected in juvenile bypass systems as kelt
stage steelhead. In this study we
evaluate two management strategies for kelt
steelhead. The first strategies, termed
no-term, collected individuals outfitted them with acoustic tags then trucked
them to a release point below Bonneville Dam.
The second management strategy termed short-term, involved feeding the
kelts for about 6 weeks before transporting and releasing the fish below
Bonneville Dam. Detection arrays were
placed near RM 90 (River); RM 25 (Estuary) ; and RM2
(Ocean). Survival from release to
detection array was not significantly different between no-term and short-term
treatments (p=0.429). Travel time from
release to detection array was significantly faster for short-term verse
no-term treatments (p=0.035). Survival
was negatively correlated with travel time for both no-term (r2=0.743)
and short-term (r2=0.648).
The highest survival was estimated for a short-term release group in
2006 with a survival estimate of 85.2% to the ocean. Overall, about 50% of the kelts released below
Bonneville Dam reached the ocean and the mortality rates appear to be about
constant from release to ocean entry.
Environmental conditions greatly influence survival to the ocean, higher
flows result to higher survival.
Utilizing this previously lost resource could lead to novel approaches to