Identifying Climate Vulnerabilities and Prioritizing Adaptation Strategies for Eulachon Populations in the Chilkoot and Chilkat Rivers and the Application of Location Monitoring Systems

Brad Ryan
Posted on: 7/18/2022 - Updated on: 1/04/2024

Posted by

CAKE Team

Published

Abstract

The Chilkoot Indian Association (CIA) assessed the climate change vulnerability and adaptation strategies of eulachon (Thaleichthys pacificus) in the Chilkoot and Chilkat rivers near Haines, Alaska. Population data was collected for the eulachon on the Chilkoot River using a mark-recapture technique and environmental DNA (eDNA). In addition a tribal stakeholder group was convened to analyze climate change projections, apply traditional knowledge, and prioritize adaptation strategies. The greatest threat to the sustainability of the northern Lynn Canal eulachon population was a lack of monitoring and the continuation of the eulachon population estimate was deemed the most important climate change adaptation strategy at this time.

Eulachon populations across the Pacific Northwest and in the upper Lynn Canal area of Southeast Alaska still suffer from incomplete baseline understandings of population health. The results of this project identified and prioritized adaptation strategies for eulachon populations and continued the development of a scientific eulachon population baseline.

The objective of this project was to advance tribally directed eulachon population research along the Chilkoot and Chilkat Rivers near Haines, Alaska, analyze data alongside the highest resolution climate projections available, and initiate a local working group of tribal experts and other stakeholders to identify and rank eulachon climate vulnerabilities and adaptation strategies, culminating in an effort to energize tribal landscape level conservation and sustainable resource management. These objectives were met through two primary activities; (1) the continuation of a eulachon population baseline dataset for the Chilkoot River, and (2) the development of a Tribal Working Group consisting of tribal leaders focused on eulachon climate change adaptation strategies.

The eulachon population estimate on the Chilkoot River followed a mark-recapture method. The Chilkoot Indian Association began monitoring the Chilkoot eulachon population in 2010 and has developed the longest eulachon population baseline data-set in northern Southeast Alaska. The data has shown that the run size returning to the Chilkoot annually varies greatly. The largest run was in 2011 with an estimate of 12.6 million fish returning to spawn. The lowest run was in 2015 and estimated 319,000 fish returning.

The large range in eulachon sawners documented through this research has necessitated the need for continued population data. The need for continued monitoring was also the single greatest threat to the eulachon population, as identified by the Tribal Working Group. Eulachon in the Chilkoot and Chilkat Rivers are not managed by a federal or state agency and there are no restrictions on harvest amounts of eulachon, which was also identified by the Tribal Working Group as a threat to the sustainability of the eulachon population. Additionally, eulachon are thought to have a low fidelity to their natal streams and may choose a spawning river from within a region rather than their specific natal stream. This regional approach to spawning also necessitates the need for a broader population estimate across the northern Southeast region.

Special acknowledgement to the North Pacific Landscape Conservation Cooperative and the Alaska Climate Science Center for providing funding for this project.

Citation

Brad Ryan, Chilkoot Indian Association (2017). Identifying Climate Vulnerabilities and Prioritizing Adaptation Strategies for Eulachon Populations in the Chilkoot and Chilkat Rivers and the Application of Location Monitoring Systems. North Pacific Landscape Conservation Cooperative and the Alaska Climate Science Center.

Affiliated Organizations

Chilkoot Indian Association

Affiliated Organizations

The NPLCC is one of 22 LCCs established by the Department of Interior. The North Pacific Landscape Conservation Cooperative is a self-directed partnership between federal agencies, states, Tribes/First Nations, non-governmental organizations, universities, and other entities to collaboratively define science needs and jointly address broad-scale conservation issues, such as climate change.

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