Auke Bay Laboratory (ABL)

Marine Salmon Interactions Program

Ocean Ecology of Salmon in Western North America: Regional Comparisons

A symposium titled Ocean Ecology of Salmon in Western North America: Regional Comparisons was held at the annual meeting of the American Fisheries Society in Anchorage in September 2005. Several ABL scientists presented papers or participated as coauthors at the symposium. Presentations by Marine Salmon Interactions (MSI) Program staff included “Mortality Rates of Chum Salmon During Their Early Marine Residency” by Alex Wertheimer, and “Assemblages of Neritic Fishes Associated with Juvenile Salmon in the California Current and the Alaska Coastal Current” by Joe Orsi. Other MSI scientists who coauthored papers at the symposium were Molly Sturdevant, Emily Fergusson, and Frank Thrower. Two additional papers included Ed Farley, Jamal Moss, and Jim Murphy of ABL’s Ocean Carrying Capacity Program as coauthors. In total, ABL scientists were senior authors or coauthors for 10 of the 18 papers presented at the symposium; the proceedings will be published as a volume in the American Fisheries Society symposium series.

By Joe Orsi.
 

Interactions of Hatchery and Wild Juvenile Chum Salmon in Taku Inlet

The Early Ocean Salmon (EOS) task of ABL’s MSI Program continued work begun in 2004 on a collaborative investigation of the ecological interactions of hatchery and wild juvenile chum salmon in Taku Inlet near Juneau. This research is funded by the Southeast Sustainable Salmon Fund to address concern about the recent decline of wild chum salmon in the Taku River that coincided with increased production of enhanced stocks of chum salmon in waters adjacent to Taku Inlet. Cooperating agencies and institutions include the University of Alaska Juneau Center for Fisheries and Ocean Sciences, the ADF&G, and the Douglas Island Pink and Chum (DIPAC) hatchery.

In 2005, the project again sampled for juvenile salmon twice weekly from mid-April until late-June using both a beach seine in littoral areas and a two-boat Kodiak trawl in nearshore waters adjacent to the littoral sites. Waters farther offshore were sampled for juvenile salmon with a larger surface trawl as part of the EOS Southeast Coastal Monitoring project, and ADF&G sampled for potential predators of juvenile salmon using small-meshed gill nets. The DIPAC hatchery chum salmon are released as juveniles at several locations near Taku Inlet; all of these hatchery releases are marked with thermally induced patterns on their otoliths.

Sample processing for 2004 collections is nearing completion. The salmon were analyzed for otolith marks to determine spatial and temporal overlap of hatchery and wild chum salmon stocks during their initial marine residency. Subsamples were then selected for further processing to compare diets and energetic conditions for evaluating the degree of competitive interactions between the two stock groups. Processing of collections from the second and final year of sampling and analysis of 2004 results will take place during the fall and winter of 2005.

By Molly Sturdevant and Alex Wertheimer


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AFSC Quarterly
Research Reports July-Sept 2005