The use of geophysical survey data in fisheries management: A case history from southeast Alaska

Primary tabs

O'Connell, V. M., Brylinsky, C. K., & Greene, H. G. (2007). The use of geophysical survey data in fisheries management: A case history from southeast Alaska. Special Paper - Geological Association of Canada, (47), 319-328.
Metadata
TitleThe use of geophysical survey data in fisheries management: A case history from southeast Alaska
AuthorsM. O'Connell, K. Brylinsky, G. Greene
AbstractThe Alaska Department of Fish and Game (ADF&G) has been conducting a habitat-based stock assessment of yellow-eye rockfish (Sebastes niberrimus) in the eastern Gutf of Alaska since 1989. Yelloweye rockfish occur in rugged rocky terrain on the continental shelf, and are an important commercial species taken in directed, and by-catch bottom-long-line fisheries. The biomass of yelloweye rockfish is derived as the product of density, average weight, and area of habitat. Density is based on line-transect surveys conducted from an occupied submersible. Area estimates of yelloweye habitat are based on the probable distribution of rocky habitat inshore of the 200 m bathymetric contour. Information used to identify rocky habitat include sidescan and multibeam sonar data (ground-truthed using direct observation from the submersible) and commercial logbook data from the directed fishery. In areas with multibeam or sidescan sonar data, the area of rockfish habitat is delineated based on defined substrate types within the mapped area. For areas without these geophysical datasets, position data from commercial fishery logbooks is used. In areas with both logbook and geophysical data, areas of habitat generally overlap but are not identical. Logbook data is mandatory, but self-reported, and may not always be accurate. Geophysical surveys reveal the extent of all rocky habitats, while fishermen target areas of prime habitat. Limiting of surveys to prime habitat may result in inaccurate stock assessments because density may remain stable in the prime habitat, while declining in surrounding habitats. By assessing fish densities in all rockfish habitats, as delineated by geophysical surveys, a better indicator of stock condition is possible. Further unlike logbook data, multibeam data allows us to clearly define boundaries of prime habitats, relevant to management decisions regarding marine reserves or to definition of management units.
JournalSpecial Paper - Geological Association of Canada
Date2007
Issue47
Start page319
End page328
Subjectsbycatch, commercial species, fish, geophysical survey, habitat type, marine park, stock assessment, Gulf of Alaska, Pacific Ocean, Sebastes, Sebastes ruberrimus

Bookmark

Bookmarks: