Kokanee salmon research

Investigating Kokanee Salmon in the Lake Washington/Sammamish Watershed

Overview

Dr. Jeffrey S. Jensen, an ichthyologist and senior lecturer at the University of Washington Bothell, leads research focusing on the distribution, history, and restoration of kokanee salmon in the Lake Washington and Lake Sammamish watershed. Kokanee are a freshwater form of sockeye salmon that remain in lakes and streams throughout their life cycle.

Historically, these small streams teemed with native kokanee, but populations have significantly declined since the early 20th century. Dr. Jensen’s work aims to determine the current presence of native kokanee in these tributaries and assess the potential for their restoration or reintroduction.

Why study Kokanee Salmon in our urban watersheds?

Urbanization has profoundly impacted the ecosystems of Lake Washington and Lake Sammamish. Habitat fragmentation, pollution, and the construction of infrastructure like the Lake Washington Ship Canal and Locks have contributed to the decline of native kokanee populations.

Understanding the current status of kokanee is vital for:

• Biodiversity Conservation: Preserving native species maintains ecological balance and supports overall biodiversity.
• Cultural Significance: Kokanee hold historical importance for local communities and Indigenous tribes.
• Ecosystem Health: As indicators of environmental health, kokanee populations reflect the condition of aquatic habitats.

Key findings

Dr. Jensen’s investigations have yielded several significant insights:

• Potential Persistence of Native Kokanee: In 2017, a peculiar run of small red fish was observed in Lake Washington’s tributaries, peaking later than typical sockeye runs. Genetic analyses indicated that these fish were most similar to, yet genetically distinct from, the native Lake Sammamish “late” run kokanee, suggesting the possible existence of a remnant native kokanee population in Lake Washington.
• Challenges in Differentiation: Distinguishing between native kokanee, residual sockeye, and hybrids remains complex. Genetic studies are essential to accurately identify and understand these populations.

Community involvement: The Salmon Watcher Program

To support ongoing research and conservation efforts, Dr. Jensen established the Salmon Watcher Program. This citizen science initiative engages volunteers in monitoring local streams for salmon activity, contributing valuable data for assessing kokanee presence and informing restoration strategies. Community participation enhances public awareness and fosters stewardship of local aquatic resources.

Future directions

Continued research focuses on:

• Comprehensive Monitoring: Expanding surveillance of tributaries to detect kokanee and understand their spawning behaviors.
• Genetic Analyses: Further studies to clarify the genetic makeup of observed populations and their relationships to known kokanee and sockeye groups.
• Restoration Efforts: Assessing habitat conditions and implementing strategies to support kokanee reintroduction and population recovery.

Dr. Jensen’s work underscores the importance of integrating scientific research with community engagement to conserve and restore native kokanee salmon in the Lake Washington/Sammamish watershed.