Publication Abstract

Predicting the effects of area closures and fishing effort restrictions on the production, biomass and species richness of benthic invertebrate communities

Predicting the effects of area closures and fishing effort restrictions on the production, biomass and species richness of benthic invertebrate communities

J. Hiddink, T.P. Hutton, S. Jennings and M.J. Kaiser

To effectively implement an Ecosystem Approach to Fisheries (EAF) managers must consider the effects of management actions on the fishery and environment. Methods for assessing the effects on target stocks are generally well developed, but methods for assessing the effects on other components and attributes of the ecosystem are not. Area closures and effort controls are widely used management tools that affect the distribution of fishing effort, with consequences for a range of species and habitats. We developed an approach for predicting the effects of area closures and effort control on the biomass, production and species richness of benthic communities in the North Sea. Redistribution of beam trawling  effort  due to management action was modelled with a random utility model, assuming that fishers  selected fishing grounds based on knowledge of past catch rates. The effects of trawling on the biomass, production and species richness of benthic invertebrates were predicted with a size-based  model that accounted  for differences in habitat among fishing grounds.  Our simulations demonstrated that closed areas could have positive or negative effects on biomass, production and species richness. Predicted effects resulted from the trade-off between recovery in the closed areas and additional trawling effects in the open areas. In the absence of effort controls, closure of lightly fished areas had the strongest positive effect on benthic communities. Any form of effort reduction also had a positive effect. Thus effort reductions, coupled with area closures in lightly fished areas, are expected to minimise fishing effects on these benthic communities in the context of an EAF. While non-availability of full international data for the North Sea beam trawl fleet made our results illustrative rather complete, we have shown how the environmental consequences of fishery management actions can be assessed.

Reference:

J. Hiddink, T.P. Hutton, S. Jennings and M.J. Kaiser (2006) Predicting the effects of area closures and fishing effort restrictions on the production, biomass and species richness of benthic invertebrate communities. ICES Journal of Marine Science, 63(5): 822-830

J. Hiddink, T.P. Hutton*, S. Jennings* and M.J. Kaiser

ICES Journal of Marine Science, 63(5): 822-830