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Fishery Bulletin 102(2) 



physicalogical condition, reduce disease incidence and 

 intensity, and decrease mortality (Lenihan, 1999). Con- 

 sequently, assessment of economics of the oyster fishery 

 over longer time frames would likely demonstrate higher 

 returns from practicing diver-harvesting, assuming that 

 this technique conserved reef structure. Diver-harvesting 

 also killed fewer of the oysters that remained on the bot- 

 tom, thereby sustaining future harvests better through 

 reduced wastage and by retention of more live oysters that 

 would produce more reef material. 



Although the relative advantage of diver-harvesting for 

 conserving reef structure is evident, the absolute conser- 

 vation of reef habitat under the various oyster harvesting 

 methods is not clear from our study. Our data on impacts 

 of diver-harvesting revealed slight declines in reef height, 

 but whether these same declines would apply to an older 

 reef, as opposed to a recently restored reef, is open to ques- 

 tion. The level of cementation that binds the shells of the 

 reef is not as great on recently restored reefs, making them 

 more susceptible to degradation with physical disturbance. 

 Our study measured only the immediate drop in reef eleva- 

 tion after fishing at a level that removed a large fraction 

 of legally marketable oysters. In a well-managed fishery, 

 this drop in reef elevation would represent virtually an en- 

 tire season's decline, after which substantial reef growth 

 would occur through recruitment and growth of smaller 

 oysters before a new harvesting season. Thus, a healthy 

 oyster reef may well be able to compensate for the modest 

 reduction in elevation caused by diver-harvesting. If so, 

 oyster reef sanctuaries now being created throughout the 

 Chesapeake Bay (Luckenbach et al., 1999) could conceiv- 

 ably be opened to diver-harvesting (without implements) 

 and still preserve the reef services to the ecosystem. This 

 possibility deserves to be evaluated in order to minimize 

 conflicts between the goals of restoring oyster reef habitat 

 for conservation purposes and restoring oyster reefs for 

 the restoration of lost fisheries. 



Application of the results of our gear comparisons to 

 management of oyster fisheries will likely encounter 

 some impediments. Although various artisanal fisheries 

 worldwide have employed free diving as a fishing tech- 

 nique and some modern fisheries, including the American 

 oyster fishery, involve the use of scuba, diving is not a skill 

 possessed by most oyster fishermen and probably is not a 

 method under consideration for oyster fishing in general. 

 In addition, the peak of oyster harvesting season on the 

 Atlantic and Gulf coasts is usually during winter months 

 (e.g., November-March) when water temperatures in 

 estuaries are quite low (0-10°C). Such conditions require 

 cold-water diving equipment (e.g., dry-suits), which will 

 further increase the cost of this new harvesting tech- 

 nique. Thus acceptance of diver-harvesting by the indus- 

 try would require training in diving skills and safety, 

 education and demonstration of the advantages of this 

 gear, and perhaps even investment of public funds to de- 

 fray costs of the transition from traditional dredges and 

 tongs to scuba or hookah. Because the gains of switching 

 to diver-harvesting accrue to the industry over the long 

 term, while individual fishermen who switch may suffer 

 economically in the short-term, gear choice represents a 



modified example of the tragedy of the commons (Ludwig 

 et al., 1993). Only when armed with some form of owner- 

 ship rights and an attendant long-term perspective would 

 an individual oyster fisherman choose to switch to diver- 

 harvesting. The precipitous declines of over 99 r < in oyster 

 landings in mid-Atlantic estuaries (Rothschild et al., 1994; 

 Lenihan and Peterson, 1998) mean that oyster fishermen 

 can hardly be expected to bear the costs of switching fish- 

 ing methods. Therefore, government intervention would 

 be required to convert subtidal oyster dredge and tong 

 fisheries into diver-harvesting operations for two reasons; 

 the need for compensation of start-up costs and the need to 

 overcome the tragedy of the commons. Given the dire state 

 of oyster fisheries today ( Rothschild et al., 1994 ), the habi- 

 tat destruction in these declines (deAlteris, 1988; Hargis 

 and Haven, 1998; Rothschild et al., 1994; Lenihan and 

 Peterson, 1998). the broad ecosystem services provided 

 by healthy oyster reefs (Jackson et al., 2001; Lenihan et 

 al. 2001), and the very real potential for restoring oysters 

 and their reefs (Luckenbach et al., 1999: Lenihan, 1999). 

 a mandate to switch fishing methods for subtidal oyster 

 fisheries could pay large dividends. 



Acknowledgments 



We thank Mike Marshall, Jeff French, and those many 

 NCDMF people working on deck for initially creating 

 experimental reefs to our specifications and for later 

 applying the experimental dredge harvesting treatment. 

 We thank Robert A. Cummings for applying the hand- 

 tonging treatment, and Jonathan H. Grabowski for help- 

 ing with diver-harvesting of reefs. This work was funded 

 by the North Carolina General Assembly through the 

 Cooperative Institute of Fisheries Oceanography (to C. H. 

 Peterson), and NOAA-Chesapeake Bay Program Oyster 

 Disease Program (to H. S. Lenihan, C. H. Peterson, and 

 F. Micheli) 



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