Functional changes as indicators of trawling disturbance on a benthic community located in a fishing ground (NW Mediterranean Sea)

Abstract

13 pages, 5 figures, 4 tables ; Trawling disturbs benthic communities, eliminating the most vulnerable organisms and modifying habitat structure. While the cumulative effects of disturbance resulting from commercial trawling activities are poorly understood, several studies suggest that chronically disturbed communities are dominated by opportunistic organisms. This study focuses on changes in functional components of the benthic community occurring in muddy sediments in a NW Mediterranean trawling ground, including an area that has not been fished for 20 yr. In both disturbed and undisturbed areas, the overall benthic community from the fishing ground was dominated by burrowing epifaunal deposit feeders and predators, and deep burrowing infaunal deposit feeders. The fished area had a higher abundance of burrowing epifaunal scavengers and motile burrowing infauna, while the undisturbed area was characterised by higher abundance of surface infauna, epifaunal suspension feeders and predatory fish. This study clearly demonstrates that changes in the functional components of a benthic community can result from fishing in areas dominated by organisms not considered especially vulnerable to trawling activities. Thus, fisheries managers aiming to reduce ecosystem disturbance must consider the implications of trawling on the structure and functioning of all types of benthic communities. ; The authors thank J. Hewitt and C. Lundquist for their helpful comments on the manuscript. This study was funded by the EU project RESPONSE (Q5RS-2002-00787). We thank the participants in the Response project, as well as all the participants in the 'Veda' cruises and the crew of the RV 'Garcia Del Cid' for their help and enthusiasm. Data were provided by the Fishermen's Association of St. Carles. S. de Juan was supported by a grant from Departament d'Universitats, Recerca i Societat of the Catalan government to study at the National Institute of Water and Atmospheric Research (NIWA), New Zealand. Comments from 3 anonymous reviewers improved the final version of the manuscript. ; Peer reviewed