Simulations of the impact of different temporal and spatial allocations of fishing effort on fishing mortality in a lobster (Homarus americanus) fishery

• Published in: Canadian journal of fisheries and aquatic sciences Vol. 59; no. 5; pp. 899 - 909
• Main Authors: Gendron, Louise, Brêthes, Jean-Claude
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.05.2002; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Crustaceans; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); Fisheries; Fishery economics; Fishing; Fishing industry; Fundamental and applied biological sciences. Psychology; Homarus americanus; Lobsters; Marine; Mortality; Magdalen Islands; Canada; North America; America; Quebec; Magdalen Islands Quebec Canada; Quebec Canada; ANW, Canada, Quebec, Madeleine Is; Canada, Quebec; ANW, Canada, St. Lawrence Gulf; ANW, Canada, Quebec, Magdalen Is; Canada, Quebec, Magdalen Is; Population exploitation; Environmental factor; Fishing; Spatial variation; Coastal zone; Pelagic zone; Macrura; Crustacea; Marine environment; Capture rate; Fishery; Seasonal variation; Arthropoda; Homarus gammarus; Decapoda; Simulation model; Invertebrata; Resource management; Dynamic model; Catch effort; Ecological abundance
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/f02-068

A spatially explicit model is proposed to assess the impact on fishing mortality of modifying effort patterns for an American lobster (Homarus americanus) fishery. A two-box (offshore and inshore grounds) model is developed for the 1995 lobster fishery season in the Magdalen Islands (Quebec). It considers lobster migration and fisher's temporal and spatial effort dynamics to estimate within-season catchability patterns and exchange rates between the two spatial units. Different management scenarios are simulated: reducing nominal fishing effort and changing its temporal (season's length) and spatial (area closures) allocations. Catchability showed a strong temporal trend, being highest during the first 3 weeks and declining regularly afterwards. The model indicated a continuous migration toward the inshore during the fishing season and that a significant amount of biomass remained offshore. As a result, reducing fishing effort at the beginning of the season would have the greatest impact on exploitation rate. Allowing less effort in the offshore area would also reduce the exploitation rate significantly. Restricting effort to the inshore area, as it was 25 years ago, reduced substantially the exploitation rate. This model represents the first attempt to analyze in-season fishery dynamics and should be useful to further assess the impact of management measures.