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Evaluating the Effectiveness of Assisted Migration and Fish Rescue Programs

Evaluating seasonally assisted migration: are fish rescue programs an effective tool for mitigating the effects of drought on coldwater fishes?
Principal Investigator
Jonathan Armstrong

Dates

Start Date
2016-09-13
End Date
2019-09-30
Release Date
2016

Summary

Climate change, drought, habitat alterations, and increasing water demands are leaving less water available for streams of the Pacific Northwest and for fish like salmon. As water levels drop, some small streams become fragmented, transforming from a ribbon of continuous habitat into a series of isolated pools. Fragmented streams may pose a serious threat to salmon. For example, juveniles that become stranded in small pools are at increased risk to overheat, starve, or be consumed by predators. Healthy salmon populations can cope with fragmentation and recover from a bad drought-year. However, many salmon populations are endangered and face long-term drought. Land and resource managers are increasingly finding endangered salmon stranded [...]

Child Items (3)

Contacts

Principal Investigator :
Jonathan Armstrong
Co-Investigator :
Thomas Buehrens, James Dixon, Kale Bentley
Funding Agency :
Northwest CSC
CMS Group :
Climate Adaptation Science Centers (CASC) Program

Attached Files

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“Studying Isolated Stream Pools - Jonathan Armstrong”
thumbnail 273.06 KB image/jpeg
IMG_1159.JPG
“Studying isolated stream pools - Credit: Jonathan Armstrong”
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“Studying Isolated Stream Pools - Jonathan Armstrong”
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IMG_1382.JPG
“Studying Isolated Stream Pools - Jonathan Armstrong”
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PhotoCopyrightDedication_Armstrong (4FishMigPics).pdf 115.63 KB application/pdf

Purpose

Climate change, habitat alterations, and increasing water demands are leaving less water available for streams of the Pacific Northwest. As water levels drop, some small streams become fragmented, transforming from a ribbon of continuous habitat into a series of isolated pools. Fragmented streams pose a serious threat to salmon; juveniles that become stranded in small pools are at increased risk to overheat, starve, or be consumed by predators. Healthy salmon populations can cope with fragmentation and recover from a bad drought-year. However, many of the salmon populations are endangered and face perennial drought. Managers are increasingly finding endangered salmon stranded in fragmented habitats, facing what is presumed to be certain death. Desperate to help, a small group of managers and conservation stewards are experimenting with fish rescue, capturing juvenile salmon from fragmented habitats and moving them to hatchery-like facilities until they grow large enough to go to sea. Fish rescue programs exist as small startups handling a tiny fraction of a population. However, there are growing demands to scale-up fish rescue by applying the technique to more fish and across more watersheds. Though fish rescue is poised for rapid expansion, no one has actually evaluated whether it is safe, effective, or feasible at scales that would have meaningful impact. Holding juveniles in captivity increases their immediate survival, but it has also been shown to reduce subsequent survival, for example by decreasing the ability of fish to feed effectively in the wild after being fed in captivity. We will measure the effects of fish rescue at multiple life-stages and analyze the costs and benefits of applying this technique across the Northwest. The final product will be a tool that allows natural resource managers to evaluate the feasibility and effectiveness of fish rescue in the context of their specific watershed and salmon population.

Project Extension

parts
typeTechnical Summary
valueLow flows associated with ecological drought can fragment stream habitats and greatly reduce fish survival. For ESA-listed fish populations there is a strong need for adaptation strategies that reduce the risks of drought-induced fragmentation. While a loud and high profile debate has ensued over the permanent translocation of species (i.e. assisted migration), a unique effort to seasonally translocate fish, termed “fish rescue”, has quietly emerged in the Pacific Northwest. Fish rescue seeks to reduce drought related mortality in wild fish by manually moving individuals from fragmented areas to either free-flowing habitat or artificial rearing facilities, providing refuge during periods of low flow. We propose to empirically and analytically evaluate fish rescue so that managers can make informed decisions about whether to apply this climate change adaptation tool more broadly throughout the region. Working with managers, we will develop a coho salmon life-cycle model that quantifies how survival across serial life-stages feeds back into population dynamics. User-parameterized equations will describe the effects of drought-induced fragmentation on juvenile survival and we will provide published parameter estimates for users lacking system-specific data. We will evaluate fish rescue through terms in the model that adjust juvenile and adult survival for the rescued segment of the population. Preliminary data suggest fish rescue increases juvenile survival to >90%, but captive rearing has also been shown to reduce subsequent adult survival; users can simulate across ranges of parameter values to evaluate the risks and benefits of applying fish rescue to their specific system. To narrow the parameter estimates for rescue effects and to directly evaluate an existing fish rescue program, we will empirically measure the survival of rescued and non-rescued coho salmon using mark-recapture techniques. Our modeling framework will help managers assess the biological trade-offs and economic feasibility of fish rescue under varying contexts of drought. We will disseminate our research through a webinar, workshop, and web-based user-parameterized model. This project will be implemented by Oregon State University in collaboration with the Washington Department of Fish and Wildlife, NOAA Fisheries, and Northwest Wild Fish Rescue.
projectStatusCompleted

Budget Extension

annualBudgets
year2016
totalFunds100018.0
year2017
totalFunds86905.0
parts
typeAward Type
valueCooperative Agreement
typeAward Number
valueG16AC00387
totalFunds186923.0

Studying isolated stream pools - Credit: Jonathan Armstrong
Studying isolated stream pools - Credit: Jonathan Armstrong

Map

Spatial Services

ScienceBase WMS

Communities

  • National and Regional Climate Adaptation Science Centers
  • Northwest CASC

Associated Items

Tags

Provenance

Additional Information

Identifiers

Type Scheme Key
RegistrationUUID NCCWSC 9d255735-fb24-47db-baca-1ea34a80aa11
StampID NCCWSC NW16-AJ0556

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