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Catastrophic Decline in Mollusc Diversity in Eastern Tasmania and Its Concurrence with Shellfish Fisheries


Edgar, GJ and Samson, CR, Catastrophic Decline in Mollusc Diversity in Eastern Tasmania and Its Concurrence with Shellfish Fisheries, Conservation Biology, 18, (6) pp. 1579-1588. ISSN 0888-8892 (2004) [Refereed Article]

DOI: doi:10.1111/j.1523-1739.2004.00191.x


We used historical patterns of deposition of mollusc shells to infer changes to inshore benthic assemblages in the southeastern Tasmanian region over the past 120 years. We identified and counted shells in slices embedded within 1m long 210Pb-dated sediment cores were collected at 13 sites in water depths of 8-16 m. Declines in mollusc species richness and shell production occurred during the past century at all sites studied, with a mean decline per 5-cm sediment slice from 21 species in 1890 to 7 species in 1990 and in shell abundance from 150 to 30 individuals over the same period. The time course of decline notably corresponded with the history of the scallop dredge fishery, presumably either because scallop dredging caused general declines in populations of mollusc species or because other factors caused a catastrophic regional decline in molluscs that included scallops. As a consequence, the fishery was forced to close. Of major concern is that losses had not previously been recognized but extended throughout the 100-km coastal span of the study. Given that fishing and other anthropogenic impacts, as well as a lack of observational data, are virtually ubiquitous for the coastal zone, major recent losses in mollusc biodiversity may be globally widespread but have gone unnoticed.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Coastal and estuarine systems and management
Objective Field:Coastal or estuarine biodiversity
UTAS Author:Edgar, GJ (Professor Graham Edgar)
UTAS Author:Samson, CR (Dr Catherine Samson)
ID Code:30850
Year Published:2004
Web of Science® Times Cited:58
Deposited By:TAFI - Zoology
Deposited On:2004-08-01
Last Modified:2005-04-19

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