The impact of eutrophication and commercial fishing on molluscan communities in Long Island Sound, USA

摘要: Abstract Benthic communities in Long Island Sound (LIS) have experienced over 150 years of commercial shellfishing and excess nutrient loading (eutrophication) which causes hypoxia. We established an ecological baseline using a combination live, dead, archaeological, fossil material to investigate the impacts these stressors on molluscan community. expected that change would increase with eutrophication-hypoxia west towards New York City. Instead we found taxonomic similarity, rank-order abundance, drilling frequency are more strongly controlled by fishing pressure than decreasing dissolved oxygen. Commercial fisherman collecting quahog clams (Mercenaria mercenaria), physically disrupt surface-dwelling organisms also kill large numbers predatory gastropods, including channeled whelk, Busycotypus canaliculatus, moonsnails Neverita duplicata Euspira heros, protect hard clam stocks. As result, areas dredged fishermen yield fewer shells drill-holes unfished sites. In spite recent reductions lobster fishing, crushing predation crabs lobsters has been suppressed below levels throughout LIS, even well oxygenated east. The absence clear relationship between questions effectiveness nitrogen reduction alone as restoration strategy. LIS fossils revealed relatively ancient loss those mollusks associated seagrass oyster habitats (e.g., oysters, Crassostrea virginica; jingle shells, Anomia simplex; scallops, Argopecten irradiens; gastropod Bittiolum alternatum) predates accumulation dead underscores need for older reveal shifting baseline. interactive nature multiple means past overfishing may dampened response eutrophication or inhibited their capactiy recover. unexpected role hypoxic protected from refuges highlights utility no-take marine preserves eutrophied estuaries worldwide.