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Juvenile Salmon Habitat and Climate Change in the Kenai River Watershed

by Benjamin Meyer

Published March 08, 2016

Aquatic Ecology Field Work

Aquatic Ecology researchers collect samples in the field.

In the Aquatic Ecology section of the EPSCoR Southcentral Test Case, we are exploring how climate change may influence habitat of juvenile Chinook (King) and Coho (Silver) Salmon in the Kenai River watershed. Juvenile Chinook and Coho Salmon live throughout the Kenai River, and the area’s diverse geography allows us to investigate how different landscapes mediate the impacts of climate change. While ongoing climate change impacts the quality and quantity of freshwater salmon habitat, the effects are not the same everywhere or necessarily negative for all salmon. As some salmon habitats decline in quality, others may improve.

Chinook Salmon fry spend up to one year in freshwater before migrating to the ocean, and Coho Salmon up to three years. Due to their long freshwater residency, environmental changes that affect rivers where young Chinook and Coho Salmon rear could be especially important relative to other salmon species that head to ocean at younger ages. Among the possible changes to young salmon habitat, water temperature and food are primary concerns. Young salmon fry generally prefer a “just right” water temperature that’s not too hot or too cold, and also rely on a diet of insects and other food items- including salmon eggs.

Aquatic Ecology Measuring Board

Juvenile Chinook Salmon on measuring board.

As air average temperature in Southcentral Alaska continue to rise, stream water temperatures will respond differently depending the streams’ water sources. Not all streams will necessarily get warmer- for example, increased glacier run-off may actually decrease summer water temperatures in some areas. What could these changes mean for juvenile salmon? We are asking these and other questions with a focus on three tributaries of the Kenai River that encompass a wide spectrum of watershed types, from lowland to montane – Beaver Creek, Russian River, and Ptarmigan Creek.

In 2015 we installed water and air temperature sensors throughout the Kenai Watershed, and collected diet and scale samples from juvenile Chinook and Coho salmon fry. In 2016 we will continue this fieldwork. As we proceed with our research, we predict our results will underscore a growing consensus that a diverse portfolio of interconnected habitats best ensures the sustainability of wild salmon populations in the face of climate change.

Aquatic Ecology Minnow Trap

UAF Master’s student Benjamin Meyer using minnow traps on Beaver Creek to capture juvenile salmon.

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