Thesis (M.S.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 70-75). Also available via Humboldt Digital Scholar.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 73-82). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 98-104). Also available via the Internet.

Thesis (M.Sc.)--College of William and Mary. / Vita. Includes bibliographical references.

Hybrid striped bass (Sunshine Bass) were raised in an indoor recirculating aquaculture system incorporating concrete culture tanks, sump tanks, rotating biological contactors and liquid oxygen injection and underground U-tubes for aeration. Fish were anesthetized by two methods after harvest to reduce metabolic activity. Hybrid striped bass were either held in cooled water or water with elevated CO₂ levels prior to sacrificing and filleting. Control fish were filleted immediately or three hours after harvest. The objectives of this study were to determine the effects of these treatments on fillet quality and to develop indicators of quality and shelf life. All fillets were stored at 1-4°C and tested over a 14-day period. Analyses included aerobic plate count, pH determination, texture measurements (Instron), color measurements (L* a* b* scale) and sensory panel evaluations of cooked portions for appearance, taste, odor and texture. Fillets of the cooled water treatment group had the highest pH and were significantly less firm (Instron). Log phase growth and the time for spoilage levels of microorganisms to grow were delayed one day in the CO₂ fillets. In addition, the CO₂ treated fillets were generally rated higher in sensory attributes than the other fillets, especially late in the test period. / Master of Science

The comparative performance of striped bass Morone saxatilis (STB) and hybrid striped bass M. saxatilis x M. chrysops (HSB) was evaluated in Claytor Lake, Virginia. This study assessed: 1) habitat use versus habitat availability for STB and HSB; 2) seasonal movement patterns, movement rates, and emigration rates of STB and HSB; and 3) angler catch rates of STB and HSB in Claytor Lake. In general, STB and HSB used similar habitats throughout this study. However, HSB used warmer (2-3'aC) water than STB during spring of 2001 and 2002. During the summer months, fish selected the coolest water temperature available that contained adequate (> 2.0 mg/L) dissolved oxygen. Striped bass habitat was more degraded than HSB habitat during summer stratification of both years. Both moronids exhibited similar seasonal movement patterns. Upstream spawning migrations took place in March at 9-10'aC. Summer habitat was restricted to the lower 1/3 of Claytor Lake, whereas fish used the entire reservoir during other seasons. Minimum daily movement rates were similar between species and seasons (0.2-0.5 km/h). Hourly movement rates were also similar between species (0.2-0.3 km/h). One tagged fish from the reservoir was recovered below the dam, suggesting low rates of emigration. Poor tag return rates by anglers limited confidence in estimation of exploitation rates. However, based on estimated natural and handling mortality rates and tag-reporting rates, estimated annual fishing mortality was 26% for STB and 14% for HSB, lower than rates found in Virginia′s Lake Gaston and Smith Mountain Lake. / Master of Science

Since the introduction of hybrid striped bass M. chrysops x M. saxatilis to Claytor Lake, Virginia in 1993, relative abundance of striped bass Morone saxatilis has dropped disproportionately to stocking density. Potentially deleterious interactions between the two fishes that may limit recruitment to age 1 were considered in terms of trophic relationships, physiological indices of health, overwinter survival, and post-stocking predation. Both fishes preferred habitat types characterized by structure-free sand or gravel substrates, but striped bass and hybrid striped bass did not exhibit significant diet overlap during the growing season. At a total length of approximately 120 mm, the juvenile moronids shifted from a mixed diet of zooplankton and invertebrates to a diet comprised primarily of age-0 fishes. However, after becoming piscivorous striped bass preyed primarily upon age-0 alewife Alosa pseudoharengus, while hybrid striped bass consumed age-0 sunfishes. Striped bass achieved mean total lengths of 229 and 173 mm by the end of the growing season in 2001 and 2002, respectively. Stocked into the reservoir three months later than striped bass, mean hybrid striped bass total lengths reached 133 mm at the end of the 2002 growing season. Condition factor, relative weight, and lipid index values were low, but nearly equivalent for both striped bass and hybrid striped bass throughout this study. Overwinter starvation of smaller (< 150 mm total length) striped bass was observed for the 2001-2002 sampling season. Predation upon stocked fingerlings was not considered significant in limiting juvenile survival; only three fingerling moronids were found in the examination of stomach contents of 200 potential predators captured near stocking sites. It does not appear that resource competition with hybrid striped bass during the growing season resulted in increased overwinter mortality of juvenile striped bass. Delayed stocking of hybrid striped bass lessens the potential for trophic competition between striped bass and hybrid striped bass at this early life-stage. / Master of Science

A 10 x 10 factorial mating design and a ‘common-garden’ rearing approach were employed to examine genetic effects and heritability of growth, carcass-quality traits, and disease resistance, important production traits in the aquaculture of hybrid striped bass (♀ white bass, Morone chrysops, crossed with ♂striped bass, Morone saxatilis). Genotypes at four to ten nuclear-encoded microsatellites were used for parentage assignment and a general, linear-mixed model and a Restricted Maximum Likelihood (REML) algorithm were used to estimate variance components associated with dam, sire, and dam x sire interaction effects. Dam and sire effect on juvenile growth (weight, length and growth rates) were significant, whereas dam by sire interaction effect was not. Estimates of broad-sense heritability for growth, based on family means (h2 f), in dams ranged from 0.60 ± 0.20 to 0.82 ± 0.10 and in sires ranged from 0.43 ± 0.20 to 0.75 ± 0.18. High correlations were found between growth rates measured at two time intervals. Estimates of general combining ability for growth rates differed significantly among dams and among sires, whereas estimates of specific combining ability for each dam × sire combination did not differ significantly from zero. These results suggest that additive-effect genes contributed to the differences in juvenile growth. Dam and sire effect on fillet weight were significant; dam effect on liver weight and sire effect on total viscera weight were also significant. Dam and sire effect on hepatosomatic index and viscerasomatic index were significant, as was dam and sire interaction effect on viscerasomatic index. Phenotypic and genetics correlations between body weight and carcass-quality traits were high (0.85 - 1.00). Phenotypic correlations between body weight and standardized carcass-quality traits were positive but low, ranging from 0.07 to 0.19. Resistance to S. iniae was assessed in a challenge experiment, using the 10 dam x 10 sire factorial mating design. A significant effect of sire on resistance to S. iniae was found, and offspring from one sire had a 2.4 times higher probability of dying than offspring from the ‘average’ sire. Genetic effects on the immune-response parameters and on stress-response parameters assessed were non-significant.

The US hybrid striped bass (Morone chrysops x M. saxatilis) industry has been negatively impacted by infectious diseases because there are very few approved drugs and vaccines. Therefore, a series of experiments was conducted to explore the potential use of various dietary supplements including autolyzed brewers yeast, the commercial prebiotic GroBiotic®, oligonucleotides and levamisole for improvement of hybrid striped bass growth, immunity and resistance to disease caused by various pathogenic bacteria. In two trials with brewers yeast, fish fed diets supplemented with yeast at 2% generally showed enhanced weight gain and feed efficiency compared with those fed a basal diet. Brewers yeast also positively influenced resistance to S. iniae infection. In addition, results of immune response assays demonstrated that brewers yeast can be administered for relatively long periods without causing immunosuppression. GroBiotic® (Grobiotic) also resulted in significantly enhanced weight gain, innate immune responses and resistance of juvenile hybrid striped bass to S. iniae infection. An additional experiment with sub-adult fish showed significantly reduced mortality of fish fed a diet supplemented with GroBiotic® at 2% when subjected to an in-situ Mycobacterium marinum challenge. This is the first report of positive effects from dietary prebiotics for fish health management, although many fundamental questions should be pursued further. Dietary supplementation of a commercial oligonucleotide product (Ascogen P®) at 0.5% of the diet was shown to enhance resistance of hybrid striped bass against S. iniae infection and increased their neutrophil oxidative radical production. However, the effect on growth was marginal. Dietary levamisole supplementation at a low level (100 mg/kg) enhanced the growth and feed efficiency of juvenile hybrid striped bass. However, an elevated dosage (1000 mg/kg diet) strongly suppressed growth, feed intake and feed efficiency. Hypothesized beneficial influences, including antibody production and resistance to S. iniae and A. hydrophila were not substantiated. Although dietary levamisole increased fish macrophage respiratory burst, an in vitro study failed to show a direct effect on cultured macrophages. This suite of studies demonstrated the potential use of some dietary supplements to enhance hybrid striped bass production. Thus, immunonutrition represents a valuable strategy to apply in aquaculture.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 113 p. : ill. (some col.), col. map. Vita. Includes abstract. Includes bibliographical references.