Spatial distribution of the relative occurrence of northern wolffish in the annual DFO groundfish research surveys conducted by the Québec (1978-2008) and Gulf (1971-2008) regions.
Catch and effort data were aggregated by 100 km² cells. The probability of catching an northern wolffish in a set and within a cell (relative occurrence) was calculated as the ratio of the number of sets in which a species was recorded and the total number of sets made. This method allows the mapping of catch and effort for numerous time series based on data from different programs in both the whole study area (research surveys and Sentinel Fisheries using bottom trawls and a random stratified design) or in specific areas within the Gulf.
Source:
Dutil, J.-D., S. Proulx, S. Hurtubise, and J. Gauthier 2011. Recent findings on the life history and catches of wolffish (Anarhichas sp.) in research surveys and in the Sentinel Fisheries and Observer Program for the Estuary and Gulf of St-Lawrence. DFO Can. Sci. Advis. Sec. Res. Doc. 2010/126: x + 71 pages.
Associated publication:
Dutil, J.-D., Proulx, S., Chouinard, P.-M., and Borcard, D. 2011. A hierarchical classification of the seabed based on physiographic and oceanographic features in the St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci. 2916: vii + 72 pages.
http:/ / www.dfo-mpo.gc.ca/ Library/ 342703.pdf.