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Salmon Scraps Boost Fish Growth in Alaska
11 Sep
Summary
- Dead salmon increased coho salmon growth and invertebrate density.
- Nutrients from salmon bodies transfer from ocean to freshwater.
- Growth benefits diminished significantly above one carcass per square meter.
A 1998 experiment in southeastern Alaska, published five years later, investigated the impact of marine-derived nutrients from salmon on freshwater fish. Researchers added varying densities of dead pink salmon, ranging from zero to four carcasses per square meter, to artificial stream channels.
Juvenile coho salmon in these channels exhibited increased growth as the amount of salmon carcass material rose. Concurrently, channels with added carcasses developed higher densities of benthic invertebrates, indicating a bolstered freshwater food web.
While initial growth gains were observed with increasing carcass additions, the benefits for coho salmon growth slowed considerably once the density exceeded one carcass per square meter.
The study also noted that cutthroat trout in a natural stream setting also grew faster with added salmon material, though they did not maintain this growth advantage through the subsequent winter.
