Modeling seasonal variation in crabbing effort: Which potential drivers and constraints are most influential?

Abstract Objective Developing credible representations about how crabbing effort may vary in response to changing conditions, such as catch rates and landings prices, is often required to model the potential outcomes of different policy options. Statistical analysis of seasonal effort data for this purpose, however, has received relatively little attention. This study evaluates the ability of alternative models that include observed fishery components to explain variation in weekly effort in the seasonal Dungeness crab Cancer magister fishery in Hecate Strait, British Columbia. A principal feature of weekly effort is that it tends to decrease linearly as an annual cohort of crabs is harvested over each annual fishing season but still shows considerable variability between weeks and between seasons. Methods Seasonal models were fitted to observed catch and effort data, provided by the Area A Crabbers Association and Fisheries and Oceans Canada. Weekly effort data was modeled using the previous week’s catch, estimated stock abundance, or the catch per unit effort. Several different models were compared, and the best-fitting model was selected using Akaike information criterion. The trap hauls were recorded by the fleet’s vessel monitoring systems. Results A seasonal model associating effort (e.g., trap hauls) with the previous week's total catch best explained weekly effort for all five fishing seasons evaluated (2003–2007); the previous week's catch fitted better than models that used catch per trap haul or previously estimated in-season abundance. The best-fitting models explained the variation in weekly crabbing effort with R2 values ranging from 0.88 to 0.95. Conclusions Landed catch in the previous week explained weekly effort better than either estimated abundance or catch rate in the previous week. This result is credible because crabbers may base their decisions on whether to go crabbing using reports of crab landings in the previous week and this information should be more readily available to them than information on the abundance of harvestable crabs and fleetwide catch rate in the previous week.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.