|Catchability and the spatial distribution of fishing vessels|
Salthaug, A.; Aanes, S. (2003). Catchability and the spatial distribution of fishing vessels. Can. J. Fish. Aquat. Sci. 60(3): 259-268
In: Canadian Journal of Fisheries and Aquatic Sciences = Journal canadien des sciences halieutiques et aquatiques. National Research Council Canada: Ottawa. ISSN 0706-652X, more
Abundance; Catch/effort; Commercial fishing; Fishing vessels; Geographical distribution; Migratory species; Stocks; Trawl nets; Gadus morhua Linnaeus, 1758 [WoRMS]; Melanogrammus aeglefinus (Linnaeus, 1758) [WoRMS]; Pollachius virens (Linnaeus, 1758) [WoRMS]; Norway [Marine Regions]; Marine
|Authors|| || Top |
- Salthaug, A., correspondent
- Aanes, S.
A central problem when using commercial catch per unit effort (CPUE) as an index of fish stock abundance is that fishing vessels search for concentrations of fish. For a given stock abundance, CPUE may become high if the vessels succeed in finding patches of fish and low if the vessels distribute their catching operations more randomly. In this work, the relationship between catchability and two measures of the degree of spatial concentration of a trawl fleet (the fleet's spatial extent and the fleet's degree of spatial patchiness) is investigated for four different fish stocks. The catchability of northeast Arctic cod (Gadus morhua) is strongly related to the fleet's degree of spatial concentration, but the relationship is weaker for northeast Arctic haddock (Melanogrammus aeglefinus), and no relationships appear for two saithe (Pollachius virens) stocks. Our findings suggest that adjusting CPUE with a measure of the fleet's average degree of concentration relates CPUE more strongly with abundance for migratory stocks.