Ecology of Small Fishes Living in Shallow Coastal Waters (Neritic Zone) in the Gulf of Alaska

A major reason we study larval fish in the Gulf of Alaska is to advance our understanding of the mechanisms that control fish population structure and production.

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Midwater trawling and sample processing (right).

Fishes are unique among vertebrates due to their exceptional diversity. Most fish begin life in the plankton (drift with ocean currents), but soon transition to a nektonic lifestyle (swim and migrate freely).

In the Gulf of Alaska, the community of small nektonic fishes in coastal midwater (neritic) habitat comprises juveniles of economically important species (e.g., walleye pollock, Pacific cod, Pacific Ocean perch and other rockfishes, sablefish, and arrowtooth flounder) and adults of other species (e.g., capelin and eulachon). All contribute importantly to the flow of trophic (food) energy that supports the fishes, seabirds, and marine mammals that characterize the piscivore-dominated Gulf ecosystem.

Our research is conducted primarily in the field. We collect small neritic fishes by midwater trawling using small-mesh nets. Sampling occurs over large geographic areas to estimate fish population size, distribution, and size composition in relation to zooplankton (prey) and environmental condition (water temperature, salinity).

We conduct laboratory work to gain insight on the biology (size, growth, condition) and ecology (food habits, local environment) of individuals. Close coupling of field and laboratory work provides insight into the mechanisms that determine fish survival and production. By studying individual fish response, we can learn more about population-level responses. 

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