Cooperative Fish and Wildlife Research Units Program: Alaska
Education, Research and Technical Assistance for Managing Our Natural Resources

The objectives of this study are to determine: 1) the biological extent of marine-derived nutrients (MDN) presence in riverine ecosystems (e.g., measure how much MDN are sequestered by fishes and other biota), 2) the magnitude of MDN influence across broad geographic scales (e.g., initially across the Yukon Delta, Yukon Flats, and into Canada within the Yukon River drainage), 3) if certain fishes benefit from the spawning runs of others (e.g., do chinook juveniles and resident fishes benefit from chum runs?), 4) roles and significance of MDN in fish health, and 5) if there is a spawner density-dependent response by consumers (e.g., do more spawners equate to greater food web effects?). Investigators predict that: 1) MDN are critically important to riverine biota across broad geographic scales, 2) fish species benefit from the spawning runs of others, 3) MDN improves fish health (e.g., fish condition, and lipid and fatty acid content), and 4) there is a density-dependent response (fish in habitats with higher spawner densities benefit more than those in habitats with fewer spawners). Data from this study will contribute to the long-term goal of constructing ecological escapement models that predict the levels of salmon returns necessary for supporting fish, wildlife and plant species, and ecosystem sustainability in Alaska.