Conservation and recovery of wild summer steelhead in the Deschutes and John Day rivers has been addressed in the final Middle Columbia River Steelhead Recovery Plan released recently by NOAA Fisheries. Anglers on these rivers are encouraged to voluntarily help these two wild steelhead populations to recover by harvesting stray hatchery fish and not fishing when water temperatures are 70 degrees F. and higher.
By removing hatchery strays from these rivers the angler is reducing the number of fish that can spawn naturally with wild native steelhead. Extensive research over the last 20 years has confirmed that when hatchery fish spawn naturally there are two effects that reduce the reproductive success of wild steelhead.
When hatchery fish cross breed with wild fish on the spawning grounds, the reproductive success and fitness of the wild fish is reduced. This impact, scientists point out, is a serious limiting factor in wild steelhead abundance and reproductive success. It is also proportional, that is, if 10% of the naturally breeding population is composed of hatchery fish the reproductive success of wild steelhead will be 10% lower and if it is 40% then wild steelhead production will be reduced by 40%.
Hatchery steelhead spawn successfully and produce juveniles that compete with wild steelhead for food and rearing space. Hatchery fish tend to spawn earlier and therefore the juveniles emerge earlier and can establish feeding territories prior to the emergence of wild steelhead. Competition for rearing space is related to size with the larger, earlier emerging juveniles having an advantage. This ecological effect means there is less rearing space available for wild steelhead in the stream. Work on the Clackamas River pointed out that naturally spawning hatchery steelhead reduced wild steelhead smolt production by 50% and even though hatchery fish produced smolts they produced very few adults. So this ecological impact reduced the wild steelhead production yet contributed very few adults from hatchery spawners to the fishery.
The angler can contribute to the success of wild steelhead reproductive success by killing all hatchery fish that come to hand, removing them as a potential threat to the wild fish and at the same time increase the abundance of wild steelhead that contribute at a much higher rate to the fisheries.
Middle Columbia River Steelhead Recovery Plan (final) 9-30-09
National Marine Fisheries Service
Deschutes River Steelhead Westside and Eastside Populations
The following harvest strategy addresses threats from out-of-subbasin hatchery steelhead strays.
Strategy: Utilize harvest to reduce the abundance and proportion of stray hatchery spawners.
Management action
1. Develop an educational outreach program to promote the use of selective recreational fisheries to reduce the number of out-of-subbasin hatchery strays. Action is designed to increase the removal of hatchery steelhead in the fisheries by promoting the increased retention of hatchery fish caught in the fisheries. Currently, many anglers release marked hatchery fish that have been hooked and landed. Fisheries managers should encourage retention of hatchery steelhead by developing an education outreach program describing the benefits to the natural populations from the retention of marked hatchery fish.
John Day River Steelhead
Strategy 1: Utilize harvest to reduce the abundance and proportion of stray hatchery
spawners.
Management action
1. Develop an education outreach program to promote the use of selective recreational
fisheries to reduce the number of out-of-subbasin hatchery strays. Action encourages
Strategy 2: Reduce catch and release mortality on natural-origin fish.
Management action
1. Promote a voluntary curtailment of fishing at higher water temperatures above 21° C (69.8 degrees F.) as a measure to reduce hook-and-release mortality. Action addresses potential fisheries impacts for steelhead in the John Day River subbasin when water temperatures are over 21° C. This may occur at the opening of the steelhead fishery in September primarily in the lower section of the river below Cottonwood Creek that is open year around.
Deschutes River water temperatures can warm to 69.8 degrees F during July, August, and September as well, and anglers can reduce live release mortality by not fishing.
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