Growth And Survival Of Striped Bass And Striped Bass Xwhite Perch Hybrids

Experiments comparing growth and survival of striped bass (Morvne saxatilis) and striped bass4? X white perch (M. americana) chybrids indicated the hybrids were hardier than striped bass under the same experimental conditions. Striped bass exhibited health problems and resulting mortality which were not evident in the hybrids. Overall survival of striped bass in 2 replicate experiments was 42.5% after II months. whereas that of the hybrids was 84.2%. Striped bass and hybrid growth patterns were similar, but striped bass grew somewhat more rapidly than the latter. Mean specific (instantaneous) growth rates were roughly similar throughout the study. with the major differences occurring during the first 4 months. At 17 months of age the mean hybrid fork length was 227.50101 (range. 167 to 282 0101). This length was approximately equivalent to that of wild populations of white perch with 4 to 8 annuli and to that of mid-Atlantic striped bass with 2 annuli, but was substantially less than that of fresh-water and more southern populations. Hybrid length-weight equations were intermediate between those of striped bass and white perch. Salinity experiments demonstrated that both small (mean fork length, 43 mm) and large (mean fork length. 279 mm) hybrids can survive and grow for indefinite periods at salinities of 18 to 25 0/00 with no signs of stress. We believe that the hybrid may be suitable as a supplement to natural populations of striped bass and white perch in estuaries.

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