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Research
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Virginia Sea Grant funded research Developing, assessing and managing a fishery for cownose ray, Rhinoptera bonasus, in Chesapeake Bay John M. Hoenig The purpose of this project is to obtain information necessary for developing, assessing and managing a fishery for cownose rays. 1) Obtain estimates of abundance. 2) Determine migration patterns and overwintering grounds. 3) Determine whether cownose rays produce one or two litters per year. 4) Estimate growth rates and longevity. 5) Synthesize life history information to produce management recommendations. An aerial survey will be used to estimate abundance of cownose rays. Migration patterns will be determined from "pop-up" satellite tagging studies. Rays will be sampled on their wintering grounds to determine reproductive activity. Growth and longevity will be determined from vertebral growth rings. Life table analysis and other models will be used to determine sustainable harvest rates. Cownose rays are now viewed as an economic nuisance to the shellfish industry and a potential impediment to oyster restoration in Chesapeake Bay. At the same time, rays present an opportunity to develop a new fishery. The history of exploitation of elasmobranch species like rays is replete with examples of boom and bust fisheries due in large part to the low intrinsic rate of population increase of elasmobranches. Thus, with care, a sustainable fishery can be developed for cownose rays but in the absence of life history information we could easily create a new conservation problem by overfishing the resource. |
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Virginia Sea Grant • Virginia Institute of Marine Science |
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