Techniques in Habitat Modelling for Stock Assessment in Canada’s Pacific Red Sea Urchin Commercial Fishery

With the move towards ecosystem based management, the Department of Fisheries and Oceans Canada (DFO) is exploring ways to use ShoreZone data as an input for habitat modelling in order to identify potential habitat in the shallow subtidal white strip for stock assessment of commercial dive fisheries. The ShoreZone data set is a georeferenced biophysical characterization of British Columbia’s shoreline based on aerial video and photography taken near zero tide. ShoreZone data were originally applied to the TRIM shoreline (Terrain Resource Information Management), whereas DFO uses a Canadian Hydrographic Services (CHS) defined shoreline. The ShoreZone have been successfully transferred to the CHS low water shoreline via a Thiessen polygon method. Integration of multiple data sets (fishing events, industry knowledge and dive surveys) from DFO with the ShoreZone data has allowed predictions of previously undefined sections of shoreline as red sea urchin habitat, or nonhabitat. Urchin habitat predictions in data-limited areas were made with varying degrees of confidence using the Biomod package in the statistics program R. Truthing of predictions is underway.