Migration Behavior and Survival of Artificially Reconditioned Kelt Steelhead Through the Lower Columbia River

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Management Strategies

• Direct Release (capture & release in-river @ Prosser, WA)
• No-term (capture, transport via truck & release below Bonneville Dam)
• Short-term (feed 4-8 weeks, transport & release below Bonneville Dam)
• Long-term (feed 7-9 months & release above Prosser, WA

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Summary

• Since the dams are highly selective against the kelt strategy, they could be altering the evolutionary trajectory of steelhead populations.
• No-term and short-term release strategies are low intervention management scenarios that allow for the recruitment of marine nutrients and are low cost.
• Kelt steelhead released below Bonneville Dam traveled quickly downstream. Many reached the ocean in 5 to 6 days.
• Short-term treated kelts traveled downstream faster than no-term treated kelts, however survival estimates between the groups was not significantly different.
• About 50% of the kelt steelhead released below Bonneville Dam reached the ocean. The mortality rate appears to be about constant from release to ocean entry. (no reach seems more important than another). Perhaps we should release fish closer to the ocean.
• Environmental conditions greatly influence survival to the ocean. Flow seems most important. High flow = greater survival.
• Utilizing this previously lost resource could lead to novel approaches to restoration.

Information Needs

• Procedures to screen kelts to predict survival.
• Reproductive success of long-term fish.
• Differential stock contribution to kelt reconditioning programs.
• Geographic replication.
• Ocean survival.

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Estuary Detection Patterns

• Direct linear progression to the ocean.
• Oscillating movement at the top of the estuary (~RM30). Movements correlated with tide. Ebb tide = downstream; Flood tide = upstream movement.