You are here

Coast Range


Assessing the Conservation of Oregon Coho Salmon

In November 2003, the State of Oregon and NOAA Fisheries began a collaborative project to address the conservation of coho salmon in the Oregon Coastal Coho ESU (Evolutionarily Significant Unit).  The primary objectives of the project are to:

  1. Assess Oregon Plan for Salmon and Watersheds efforts to conserve and rebuild coastal coho populations.
  2. Use the assessment to inform NOAA Fisheries' status review listing determination.
  3. Use the assessment as a basis to seek legal assurances for local participants.
  4. Use the assessment as a foundation for developing a recovery plan for coho.

Image courtesy of the National
Oceanic and Atmospheric Administration

The framework for this Assessment included developing measurable criteria to define population and ESU viability, utilizing the best available information to evaluate fish status relative to these criteria, identifying key factors likely responsible for the evaluation result, assessing the implementation certainty and effectiveness of conservation efforts to address factors for decline and potential threats to viability, and concluding with Oregon's overall evaluation of what threats to this ESU remain and what the significance of those threats is in terms of risk to viability. To accomplish this, various types of data were examined, including: fish abundance and distribution; marine survival; fishery harvest; hatchery programs; stream complexity; riparian condition; water quality; streamflow; fish passage (access to spawning and rearing streams); predation; fish disease; and exotic fish species. These data represent available information collected both before and after the formal implementation of the Oregon Plan in 1997.

In late 2005, the State of Oregon released an executive summary of its assessment of the Oregon Coastal Coho ESU.  Click  here to access this document.  Key conclusions for the entire Oregon Coastal Coho ESU include:


Image courtesy the Oregon
Watershed Enhancement Board

  • The Coastal Coho ESU is viable, that is, coho populations generally demonstrate sufficient abundance, productivity, distribution and diversity to be sustained under the current and foreseeable range of environmental conditions. In fact, the ESU retains sufficient productivity and is supported by sufficient habitat to be sustainable through a future period of adverse ocean, drought, and flood conditions similar to or somewhat more adverse than the most recent period of poor survival conditions (late 1980s and 1990s).
  • Oregon concluded that two risk factors (marine habitat and stream complexity) currently present moderate levels of risk to future ESU viability.
  • Stream complexity and water quality were the two most commonly identified population bottlenecks, regardless of whether populations were or were not classified as viable.
  • Other risk factors that were identified as primary population bottlenecks include: hatchery impacts (two populations), exotic fish species (three populations), water quantity (two populations), and spawning gravel (one population).
  • Historical land, water and fish management activities that were the key contributing factors for the legacy of coho declines have been stopped.
  • Monitoring of habitat and water quality since 1997 provides a baseline to detect future trends (positive or negative) that could affect ESU viability. The sensitivity (ability to detect change) of monitoring will increase substantially in the next 3-8 years as more data become available.

On January 17, 2006, the National Oceanic and Atmospheric Administration's Fisheries Service (NOAA Fisheries Service) announced that Oregon coastal coho are not likely to become endangered and will not be listed under the Endangered Species Act (ESA).

According to NOAA Fisheries, "An in-depth assessment by Oregon concluded that state actions to reform harvest and hatcheries had helped turn the coho population around, and that the population's ability to rebound from very low levels demonstrated that it is likely to persist into the future. NOAA Fisheries Service agreed with the Oregon analysis, although noted there are many uncertainties about what the future holds for the coho. Oregon and NOAA Fisheries Service will continue to monitor coho for population changes."

The Coastal Coho ESU Assessment is the starting point for more effective future restoration investment, monitoring, and adaptive management action. Regardless of the current ESA listing decision, Oregon, in partnership with NOAA Fisheries and interested stakeholders, will continue the ongoing process of completing a full conservation/recovery plan. This plan builds upon the Assessment to establish goals beyond the threshold of viability, focuses management actions on the primary limiting threats to reaching those goals, and establishes a comprehensive monitoring and evaluation program for adaptive management. The draft conservation/recovery plan is scheduled to be completed by the end of 2006.


The Oregon Plan for Salmon and Watersheds 2003-2005 Biennial Report, Volume 2 - Executive Summary of Oregon's assessment of the Oregon Coastal Coho Evolutionarily Significant Unit (ESU)

Oregon Coastal Coho Assessment