Clam fisheries worldwide: Main species, harvesting methods and fishing impacts

This chapter presents a comprehensive compilation of information available on fisheries targeting bivalves belonging to the family Veneridae worldwide. Based on an extensive search of data, from both bibliographic references and web-sites, the chapter provides information on the most important clam fisheries, the main harvesting methods and fishing gears employed to target venerids, and the respective impacts on the marine environment. Overall, it was gathered information concerning the exploitation of 36 genera and at least 89 species of venerids, which are caught worldwide using quite different harvesting methods and fishing gears. Depending on where the bivalves occur (intertidal flats vs. subtidal areas) and on the type of fishery (subsistence, recreational or commercial), harvesting can be performed through highly diverse methods, from very simple and rudimentary techniques (e.g. hand picking) to sophisticated gears (e.g. hydraulic dredge). Accordingly, the extent and magnitude of bivalve fishing impacts on the marine ecosystems depend on the combined influences of local hydrodynamic and environmental conditions (currents, tidal strength, water depth, nature of the substrata and structure of the benthic communities) and the type and intensity of the fishery (type of gear, fishing frequency, towing speed and gear penetration into the sediment).