Hatchery propagation did not reduce natural steelhead productivity relative to habitat conditions and predation in a mid-Columbia River subbasin

Abstract

For over 150-years, hatchery-origin anadromous salmon and trout have been reared and released throughout the Pacific Northwest to mitigate for lost habitat and sustain harvest opportunity. Some studies demonstrate that introgression of hatchery and naturally produced fish may constrain conservation efforts through maladaptive genetic processes. However, empirical demonstrations of the influence of these genetic interactions on population productivity are lacking, making it difficult to assess their importance relative to other drivers of productivity. We estimated the effect of the proportion of hatchery-origin spawners (pHOS), proportionate natural influence (PNI), and hatchery fish releases on natural adult winter steelhead recruitment in the Hood River, Oregon over a 27-year period of record. Adult winter steelhead productivity was not associated with pHOS and PNI. However, natural winter steelhead productivity was positively associated with ocean conditions, stream flow, and hatchery fish release numbers, while negatively associated with pinniped abundance. Our analysis highlights the importance of quantifying the influence of hatchery programs on fish production relative to environmental factors known to affect natural-origin anadromous fish recruitment.

Genetic monitoring of steelhead in the Klickitat River to estimate productivity, straying, and migration timing

“…This biological opinion calls for the percent of hatchery‐origin spawners (pHOS) on natural spawning grounds of 5.0% or less, but pHOS is not easily estimated on the Klickitat River due to a low number of steelhead carcasses recovered most years during spawner surveys that co‐occur with high spring flows. However, these pHOS measures may not directly influence productivity of natural‐origin steelhead (Courter et al 2022) and other approaches to evaluating the effects of hatchery programs may be necessary. While the National Marine Fisheries Service gene flow metric may not be directly comparable to the results presented here, the available measures from this study indicate a generally low level of gene flow between Skamania Hatchery steelhead and natural‐origin Klickitat steelhead populations.…”

Fisheries Volume 48 Number 10 October 2023

“…For more information: https://afsannualmeeting.fisheries.org COLLINS et al spring flows. However, these pHOS measures may not directly influence productivity of natural-origin steelhead (Courter et al 2022) and other approaches to evaluating the effects of hatchery programs may be necessary. While the National Marine Fisheries Service gene flow metric may not be directly comparable to the results presented here, the available measures from this study indicate a generally low level of gene flow between Skamania Hatchery steelhead and natural-origin Klickitat steelhead populations.…”

New Journal Design

“…spring flows. However, these pHOS measures may not directly influence productivity of natural-origin steelhead (Courter et al 2022) and other approaches to evaluating the effects of hatchery programs may be necessary. While the National Marine Fisheries Service gene flow metric may not be directly comparable to the results presented here, the available measures from this study indicate a generally low level of gene flow between Skamania Hatchery steelhead and natural-origin Klickitat steelhead populations.…”