9328

• UCREFRP Catalog Number: 9328
• Author: Miller, W. H.
• Title: Analysis of Salmon and Steelhead Supplementation.
• USFW Year: 1990.
• USFW - Doc Type: \
• Copyright Material: NO

ABSTRACT
Supplementation or planting salmon and steelhead into various locations in the
Columbia River drainage has occurred for over 100 years. All life stages, from eggs to
adults, have been used by fishery managers in attempts to establish, rebuild, or maintain
anadromous runs. This report summarizes and evaluates results of past and current
supplementation of salmon and steelhead. Conclusions and recommendations are made
concerning supplementation.
Hatchery rearing conditions and stocking methods can affect post release survival of
hatchery fish. Stress was considered by many biologists to be a key factor in survival of
stocked anadromous fish. Smolts were the most common life stage released and size of
smolts correlated positively with survival. Success of hatchery stockings of eggs .and pre-
smolts was found to be better if they are put into productive, underseeded habitats.
Stocking time, method, species stocked, and- environmental conditions of the. receiving
waters, including other fish species present, are factors to consider in supplementation
programs.
The unpublished supplementation literature was reviewed primarily by the authors of this
report. Direct contact was made in person or by telephone and data compiled on a
computer database. Areas covered included Oregon, Washington, Idaho, Alaska,
California, British Columbia, and the New England states working with Atlantic salmon.
Over 300 projects were reviewed and entered into a computer database. The database
information is contained in Appendix A of this report.
Our conclusions based on the published literature and the unpublished projects reviewed
are as follows:
-Examples of success at rebuilding self-sustaining anadromous fish runs with hatchery
fish are scarce. We reviewed 316 projects in the unpublished. and ongoing work.
Only 25 were successful for supplementing natural existing runs, although many were
successful at returning adult fish.
-Successes from outplanting hatchery fish were primarily in harvest augmentation, a
term we use to describe stocking where the primary purpose is to return adults for
sport,rtribal or commercial harvest.
-Adverse impacts to wild stocks have been shown or postulated for about every type of
hatchery fish introduction where the intent was to rebuild runs.
-Reestablishing runs or introductions to areas not inhabited by wild/natural populations
have shown good successes.
-The stock of fish is an important factor to consider when supplementing. The closer
the hatchery stock is genetically to the natural stock, the higher the chances for
success.
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