| Abstract: | In 1978 a cooperative pilot study was initiated by the Marine Resources Research Institute and DØMSEA Farms, Inc. to examine the feasibility of rearing striped bass (Morone saxatilis) x white bass (M. chrysops) hybrids to marketable pan-size in estuarine net-pens. The first study was begun in July 1978 when a total of 1,070 hybrid fingerlings (mean weight, 1.7 g) were stocked in 3.05 × 2.44 × 1.83 m deep net-pens moored to a commercial marina dock on the Stono River near Charleston, S.C. During the first month these fish suffered a 76% mortality, apparently as a result of feeding only a dry salmon ration. Thereafter, the remaining fish were fed the dry ration mixed approximately half-and-half with ground fish. At the end of one year, these fish had attained a mean weight of 523.0 g, with 74.6% survival. A second experiment was begun in July 1979 when 900 hybrid fingerlings (mean weight, 3.0 g) were stocked in each of three 3.05 × 2.44 × 1.83 m net-pens at the marina (stocking density, ?66 fish/m3). The fish were fed a mixture of dry salmon feed and ground fish throughout. At the end of one year, survival and weight averaged 88% and 310.2 g, respectively. Biomass in the pens at this time averaged 16 kg/m3. Little growth or active feeding occurred at temperatures < 15°C. In contrast, salinity variations had no apparent effect on growth. However, a period of decreasing salinity in early spring coincided with an outbreak of a bacterial disease (cf. Vibrio anguillarum) among striped bass fingerlings reared in adjacent pens. Fish which had been treated with a vaccine solution did not succumb to the disease, while approximately 50% mortality occurred among non-vaccinated fingerlings. |
