Impact of a large-scale area closure on patterns of fishing disturbance and the consequences for benthic communities

Seasonal area closures of fisheries are primarily used to reduce fishing mortality on target species. In the absence of effort controls, fishing vessels displaced from a closed area will impact fish populations and the environment elsewhere. Based on the observed response of the North Sea beam trawl fleet to the closure of the "cod box" and an existing size-based model of the impacts of beam trawling, we predict the effects of seasonal area closures on benthic communities in the central North Sea. We suggest that repeated seasonal area closures would lead to a slightly more homogeneous distribution of annual trawling activity, although the distribution would remain patchy rather than random. The increased homogeneity, coupled with the displacement of trawling activity to previously unfished areas, is predicted to have slightly greater cumulative impacts on total benthic invertebrate production and lead to localized reductions in benthic biomass for several years. To ensure the effective integration of fisheries and environmental management, the wider consequences of fishery management actions should be considered a priori. Thus, when seasonal closures increase the homogeneity of overall disturbance or lead to the redistribution of trawling activity to environmentally sensitive or previously unfished areas, then effort reductions or permanent area closures should be considered as a management option. The latter would lead to a single but permanent redistribution of fishing disturbance, with lower cumulative impacts on benthic communities in the long run

Are marine protected areas a red herring or fisheries panacea?

Author Posting. © National Research Council Canada, 2005. This article is posted here by permission of National Research Council Canada for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences 62 (2005): 1194-1199, doi:10.1139/F05-056.Chronic failures in marine fisheries management have led some to suggest that marine protected areas (MPAs) are the solution to achieve sustainable fisheries. While such systems work for certain habitat-specific and nonmobile species, their utility for highly mobile stocks is questionable. Often the debate among proponents and critics of MPAs is confused by a lack of appreciation of the goals and objectives of such systems. The current consideration of MPAs as the basis of future fisheries management is a symptom of, and not the singular solution to, the problem of inappropriate implementation of fishing effort controls. The latter will provide greater overall conservation benefits if properly applied. Any future use of MPAs as an effective tool to achieve sustainable fisheries management in temperate systems should be treated as a large-scale, rigorously designed experiment to ensure that the outcome of using MPAs is interpreted correctly and not discredited for false reasons