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Assessing the resilience of southeast Alaskan salmon to a shifting freshwater environment

Investigators

Jeffrey Falke Jeffrey FalkeAlaska Cooperative Fish and Wildlife Research Unit
U.S. Geological Survey
Ryan Bellmore Ryan BellmorePacific Northwest Research Station
US Forest Service
Rebecca Bellmore Rebecca Bellmore
Southeast Alaska Watershed Coalition
Davin Holen Davin HolenMarine Advisory Program
University of Alaska Fairbanks

Student

Synopsis

Salmon are important economic, subsistence, and cultural resources for Alaskans. The forest stream ecosystems that salmon depend on for spawning and rearing are already responding to climate change and are likely beginning to influence salmon growth and survival at multiple stages of their life cycle. In contrast to threatened and endangered populations of salmon in the Lower 48, we have an unprecedented opportunity to prioritize future management actions for freshwater ecosystems in a region where salmon populations are generally still healthy. Researchers propose to model and predict the implications of shifting stream temperature and discharge regimes on salmon productivity in Southeast Alaska, where in the coming decades climatologists predict increasing air temperatures, increased annual rain accumulation, and decreasing precipitation falling as snow. Researchers will work with tribal partners to focus research on anadromous streams that are important for subsistence, as well as document local observations as to which streams are being impacted by changing climate conditions. Results will be shared with communities via local meetings and contribute to scenario-­planning exercises that explicitly incorporate stakeholder input into future proposed management actions. User-­friendly models developed as part of this project will be made publicly available, and communities will receive training to adapt them to local systems.

Overview

The issue

Salmon that spawn and rear in Southeast Alaska (SEAK) forest streams are critically important to the region’s economic vitality and cultural identity. Environmental changes that compromise the ability of these streams to support salmon could have dramatic consequences for the region. In particular, there is concern that climate change could undermine the capacity of SEAK streams to support productive fisheries via alterations to water temperature and flow regimes via impacts on multiple freshwater life stages. Although life-cycle models that track salmon growth and survival across life stages have been developed for many at-risk populations throughout the southern range of salmon there have been limited efforts to expand this approach northward to Alaska. Broad-scale stream temperature and flow monitoring networks are beginning to provide much-needed data to quantify the effects of climate variability on salmon growth and survival. However, gaps exist and many watersheds that provide critical subsistence opportunities for local communities are not monitored.

Why is this an Alaska Sea Grant project?

This project directly addresses the 2018-2021 Alaska Sea Grant Strategic Plan. Specifically, the project would increase the shared body of knowledge on watershed ecosystems in Southeast Alaska and the effects of climate change on the capacity of these watersheds to sustain resources critical to communities (Healthy coastal ecosystems – Objective 1). Importantly, the project has a long list of established partners, which will ensure that the project incorporates priority systems and stakeholder concerns (Strategy 1). We will work with tribal partners to focus research on anadromous streams that are important for subsistence, as well as document local observations and initiate community monitoring for streams being impacted by changing climate conditions (Strategies 2 & 5). Results will be shared with communities via local meetings and contribute to scenario-­planning exercises that explicitly incorporate stakeholder input into future proposed management actions (Strategies 3 & 4). User-friendly models developed as part of this project will be made publicly available, and communities will receive training to adapt them to local systems (Strategy 4). By identifying streams and salmon populations that are at risk of declining, this project can inform ecosystem management and enhance the capacity of Southeast Alaska communities to adapt and respond to climate change.

Research collaborators

U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit
Institute of Arctic Biology, UAF
College of Fisheries and Ocean Sciences, UAF
U.S. Forest Service, Pacific Northwest Research Station
Southeast Alaska Watershed Coalition
Tongass National Forest
Southeast Alaska Fish Habitat Partnership
Chichogof Conservation Council
Sitka Tribe of Alaska
Central Council of Tlingit and Haida Indian Tribes of Alaska
National Park Service, Southeast Alaska Inventory and Monitoring Network