Conserving oyster reef habitat by switching from dredging and tonging to diver-harvesting
The University of North Carolina at Chapel Hill University Libraries
Abstract
A major cause of the steep declines of American oyster (Crassos- trea virginica) fisheries is the loss of oyster habitat through the use of dredges that have mined the reef substrata during a century of intense harvest. Experiments comparing the efficiency and habitat impacts of three alternative gears for harvesting oys- ters revealed differences among gear types that might be used to help im- prove the sustainability of commercial oyster fisheries. Hand harvesting by divers produced 25−32% more oysters per unit of time of fishing than tradi- tional dredging and tonging, although the dive operation required two fish- ermen, rather than one. Per capita returns for dive operations may none- theless be competitive with returns for other gears even in the short term if one person culling on deck can serve two or three divers. Dredging reduced the height of reef habitat by 34%, sig- nificantly more than the 23% reduction caused by tonging, both of which were greater than the 6% reduction induced by diver hand-harvesting. Thus, con- servation of the essential habitat and sustainability of the subtidal oyster fishery can be enhanced by switch- ing to diver hand-harvesting. Man- agement schemes must intervene to drive the change in harvest methods because fishermen will face relatively high costs in making the switch and will not necessarily realize the long- term ecological benefits.