An examination of chronic trawling effects on soft-bottom benthos of the eastern Bering Sea

Abstract

The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996. Samples of 92 taxa (reduced for analysis) were collected at 84-1 nm 2 sites straddling a closed-area boundary. Multi-and univariate statistical tests and raw patterns in the data support the following generalizations: (1) sedentary macrofauna (e.g., anemones, soft corals, sponges, whelk eggs, bryozoans, ascidians), neptunid whelks, and empty shells were more abundant in the UF area; (2) mixed responses were observed within motile groups (e.g. crabs, sea stars, whelks) and infaunal bivalves, suggesting the importance of life history characteristics, such as habitat requirements and feeding mode; and (3) overall diversity and niche breadth of sedentary taxa were greater in the UF area. A systematic approach is required to address the complex issue of bottom-trawl disturbances. This begins with the identification of chronic and acute impacts, followed by focused investigations of ecological implications and, ultimately, cost-benefit analyses to evaluate specific resource-management options.2000 International Council for the Exploration of the Sea

Effects of marine protected areas on fisheries: the case of São Paulo State, Brazil

“…Despite usually applied regulations, pair trawl fishery has been discussed worldwide because of impacts on the population of target species as well as on populations of species incidentally caught, in benthic organisms and on their habitats (McConnaughey et al, 2000;Kaiser et al, 2002;FAO, 2009). It is characterized by the use of a low selectivity gear and by the high bycatch rate for capturing non-commercial organisms or juveniles of commercial species without market value.…”

Assessing the Impacts of Establishing MPAs on Fishermen and Fish Merchants: The Case of Lyme Bay, UK

“…MPAs are considered an essential means of delivering an ecosystem-based approach to management, being able to protect and conserve species, habitats, ecosystems and ecological processes (Goni et al 2000;Garcia-Charton et al 2000;Gell and Roberts 2003;Roberts et al 2005). Following concerns about the damage caused by mobile fishing gear on the structure and complexity of ecosystems, and the increase in scientific evidence of such damage (e.g., Currie and Parry 1996;Watling and Norse 1998;McConnaughey et al 2000;Kaiser et al 2000;Kaiser et al 2002;Kaiser et al 2006;Tillin et al 2006), the UK Government took advice from its conservation advisors (Natural England) and in July 2008, closed part of the Lyme Bay reefs to scallop dredging and demersal trawling gear to protect marine biodiversity against damage incurred as a result of towed benthic gear. This statutory closure represents a major attempt on the south coast of the UK to implement an MPA as a tool to protect marine life.…”

Ecological effects of bottom trawling on the structural attributes of fish habitat in unconsolidated sediments along the central California outer continental shelf

“…However, a limitation common to the few existing studies of impacts of trawling along the West Coast of the United States (Engel and Kvitek, 1998;Freese et al, 1999;McConnaughey et al, 2000;Hixon and Tissot, 2007;de Marignac et al, 2009) was the fact that trawling effort was not controlled as part of these studies. These studies, although instructive, have been either 1) snapshots based on data collected after trawling, 2) studies with little knowledge of the intensity of trawling effort in the area studied, or 3) both.…”