Acute and Sublethal Effects of Ammonia on Striped Bass and Hybrid Striped Bass

Bioassays in static water (mean ± SD; temperature, 20–22 C; pH, 8.2–8.4; alkalinity, 205 ± 10 mg/L CaCO₃; total hardness, 220 ± 10 mg/L CaCO₃) were used to determine median lethal concentrations (LC₅₀) of un-ionized ammonia (NH₃-N) for striped bass Moronc saxatilis and hybrid striped bass M. saxatilis × M. chrysops. The 96 h LC₅₀ for striped bass was 1.01 ± 0.24 mg/L NH₃-N₃ and was significantly higher than the LC₅₀ for hybrid striped bass (0.64 ± 0.05 mg/L NH₃-N). The effects of sublethal ammonia were evaluated after fish were exposed for 96 h to 0.0, 0.25, or 0.5 mg/L NH₃-N or to additional exposure to oxygen depleted water (about 2.0 mg O₂/L). Plasma ammonia of striped hass did not change as sublethal ammonia increased, but exposure to oxygen depletion caused a decrease in plasma ammonia. In contrast, plasma ammonia of hybrid striped bass increased as environmental ammonia increased, and increased further after exposure to oxygen depletion. Plasma cortisol levels of striped bass were significantly higher and more variable than cortisol levels of hybrid striped bass; additional exposure to oxygen depletion increased this variability, but these responses may be due to the stress of handling and confinement. Mean differences also existed between species for hemoglobin and hematocrit, while differences in variability occurred for osmolality and oxygen depletion rates. Striped bass tolerated ammonia better than hybrid striped bass but were more susceptible than hybrid striped bass to the additional stress of oxygen depletion. Most changes in physiological characteristics were relatively independent of environmental ammonia, but they were affected by oxygen depletion challenge.     

Oxytetracycline Residue in Hybrid Striped Bass Muscle

Hybrid striped bass ( Morose saxatilis male × M. chrysops female) were injected with 25 and 50 mg oxytetracycline (OTC) per kg of fish. Rate of elimination of OTC from muscle tissue and inhibition of bacteria by muscle injected with OTC were studied. OTC residue in muscle of fish injected with 50 mg OTC/kg fish was much higher (P < 0.01) than that in fish injected with 25 mg/kg and took a longer time to clear from the muscle. In fish injected at 25 mg OTC/kg of fish, OTC was completely eliminated from muscle in 24 d; the rate of elimination constant (β) was 0.278/day and the half-life (t_1/2) 2.5 d. In fish injected at 50 mg OTC/kg of fish, the OTC was not depleted in fish muscle until 32 d after injection; the rate of elimination constant 13 was 0.265/day and the half-life was 2.6 d. No statistical difference was found in muscle OTC residue between male and female fish. Size of fish (16.5 to 21.5 cm and 21.6 to 25.5 cm) made little difference in OTC residue in muscle. Muscle removed from fish injected with 25 mg/kg OTC 12 d after injection inhibited the growth of Vibrio anguillarum, V. ordalii and Aeromonas hydrophila in cultures.     

Production Characteristics of Striped Bass × White Bass and Striped Bass × Yellow Bass Hybrids

The potential for commercial culture of hybrid striped bass is promising in many areas of the United States. While several different striped bass hybrids are candidates for culture, differential performance has not been thoroughly evaluated. Comparative performance of two striped bass hybrids was evaluated in six, 757–1, fiberglass tanks receiving a continuous flow of ambient pond water for 397 d. Three replicate tanks were stocked with 50 fingerlings (66 fish/m³) of either striped bass female × white bass male (mean weight 23 g) or striped bass female × yellow bass male hybrids. Fish were fed a 35% protein ration throughout the study, and weight was recorded for all fish at stocking and at 21-d intervals. White bass hybrids grew significantly faster (0.94 g/d) than yellow bass hybrids (0.59 g/d). Survival to harvest averaged 65% and 44% for yellow bass and white bass hybrids, respectively. A significant difference from the expected 1:1 sex ratio occurred for yellow bass hybrids (100% female), but not for white bass hybrids (56% female). Mean condition factor, 1.63 and 1.39, and fillet percentage, 30.7% and 28.4%, was significantly higher for white bass hybrids compared to yellow bass hybrids.     

Performance of Domesticated Striped Bass Morone saxatilis, Palmetto Bass and Backcross Hybrid Striped Bass (Sunshine Bass ♀× Striped Bass ♂) Raised in a Tank Culture System

Abstract— Grow-out performance of striped bass Morone saxatilis , palmetto bass ( M. saxatilis ♀ × M. chrysops ♂ ) and backcross hybrids [sunshine bass ♀( M. chtysops ♀ × M. saxatilis ♂) × M. saxatilis ♂] was examined in a two-part study. During part I fish (mean weight = 20.1 g) were stocked at a density of 56 fish/m³ in 1.8-m³ cylindrical fiberglass tanks connected to a central biological filter. Fish were fed a 38% protein trout ration daily and the study duration was 273 d. At harvest, no differences ( P > 0.05) in mean weight or feed conversion were detected among the fish types. However, there were differences in specific growth, with the striped bass having a significantly higher growth rate than the palmetto bass and the backcross hybrids being intermediate. The condition factor (K) for striped bass was also significantly lower (1.2) than that recorded for either of the other two groups. In addition, survival of striped bass (91%) was significantly higher than that of backcross hybrids (74%), while survival of palmetto bass (87%) was intermediate. The survival of backcross hybrids was adversely impacted by an infestation of the dinoflagellate Amyloodinium sp . During part II stocking density in each tank was reduced to 19 fish/m³. The study lasted 104 d. At harvest, no differences were detected in weight, survival, or feed conversion. However, there were significant differences in specific growth, length and K. Striped bass and backcross hybrids gained weight faster than palmetto bass. Length and K were inversely related with all groups being significantly different. Striped bass had the largest TL and the lowest K while, palmetto bass were the shortest with the highest K.     

Economies of Pond Size for Hybrid Striped Bass Growout1

The objective of this study was to evaluate the relationship of pond size and hybrid striped bass growout profitability as an alternative source of farm income in the Mid-Atlantic region. A dynamic, whole farm, Montdarlo capital budgeting simulation model (AQUASIM) and stochastic dominance with respect to a function technique were used to analyze the economics of hybrid striped bass growout from phase II to market production stage for eight farms categorized by pond sizes. Three scenarios are assumed to examine the effects of pond-size dependent changes in feed conversion efficiency and fingerling survival rates on discounted after-tax net present values and probabilities of economic survival and success. Optimal pond sizes were found to be in the 2.5 acre to 10 acre range.     

杂交条纹鲈含肉率及鱼肉营养成分分析

报道了杂交条纹鲈含肉率及鱼肉营养成分的测试结果。该鱼含肉率为71．96％，鱼肉蛋白质的含量为17．89％，脂肪为8．64％；17种氨基酸的总量为17．10％，其中7种必需氨基酸含量为6．63％；4种鲜味氨基酸总量为7．18％，其中谷氨酸2．87％、天冬氨酸1．75％、甘氨酸1．25％、丙氨酸1．31％；并与其它养殖鱼类的营养成分进行了比较。     

Increased Growth and Production of Striped Bass × White Bass Hybrids in Earthen Ponds

Four 0.1 hectare earthen ponds were stocked with 16,500 hybrid striped bass (female Morone saxatilis × male M. chrysops ) per hectare on 22 June 1982. Mean weight at stocking was 5.2 g ± 0.10 SE. Fish were fed to satiation two or three times daily with a dry commercial salmonid diet, and the ponds were aerated mechanically during periods of low dissolved oxygen during warm weather. Survival at harvest on 6 March 1983 averaged 84.7%, and mean weight of the fish was 170.2 g ± 2.66 SE. Average weights of fish from individual ponds ranged from 149.0 to 189.7 g. The ponds were restocked on 1 April 1983 with 10,000 fish per hectare averaging 193.6 g. Ten months later, average survival in 3 ponds was 83.9% (range, 81.3–87.0%) and mean weight was 656.3 g ± 5.51 SE. Average weights of fish from individual ponds ranged from 632.5 to 690.7 g. All fish in one pond died in June as a result of an aerator failure. Standing crop at harvest in the three remaining ponds averaged 5, 504 kg/ha (range, 5,247–5,765 kg/ha). Improvements in culture techniques resulted in approximately a 138% increase in production per hectare over that reported in a prior study. Results demonstrated that hybrid striped bass offer considerable potential for commercial aquaculture in warm temperate latitudes of the United States.     

Experimental and Practical Diet Evaluations with Juvenile Hybrid Striped Bass1

Culture of hybrid striped bass has been expanding in the United States and further growth has been predicted, however, several problem areas exist, including a lack of nutritional information. This series of studies offered reciprocal cross juvenile hybrids several of the commercially available feeds and several different types of purified experimental diets. Weight gain and feed efficiency of fish fed the commercially available feeds formulated to meet the general requirements of salmonids were better than fish fed feeds formulated to meet the nutritional requirements of catfish. Experimental diets containing casein as the primary protein source were unpalatable regardless of the level of fish oil added (6 or 12%) but were accepted if 10% menhaden fish meal was added. Addition of lower levels of fish meal resulted in decreasing degrees of acceptance. Thus, the minimum level of fish meal that elicited a feeding response appeared to be between 510% of the dry diet. A crystalline amino acid test diet was palatable, and weight gain of fish fed that diet was 65–91% of the weight gain recorded for fish fed the positive control diets. Addition of L-arginine, L-methionine or L-cystine to a purified diet containing casein did not result in dietary acceptance. Whole-body proximate composition offish revealed a general trend toward increased lipid levels with increasing levels of dietary lipid. All fish exhibited microvessicular hepatopathy, regardless of diet fed. Hepatocytes contained both glycogen and lipid in the cytoplasm.     

Acceptance and Consumption of Food by Striped Bass and Hybrid Larvae

Food acceptance, consumption and weaning times were investigated for striped bass ( Morone saxatilis ) and hybrid striped bass ( M. saxatilis × M. chrysops ) larvae. Experimental treatments consisted of: control groups of striped bass (SC) and hybrids (HC) fed Artemia nauplii; hybrids fed formula food (HF); and hybrids weaned from Artemia nauplii to formula food at 11–15 days (HF₁), and 18–22 days (HF₂) posthatch. The formula diet did not support growth and resulted in total mortality of the HF hybrids by the third week posthatch. HF₁ fish had significantly slower growth and lower survival than HF₂ of HC. The HF₂, HC and SC groups had similar growth and survival, which indicated no heterosis in hybrids. There were no differences in Artemia nauplii consumption by the SC and HC groups. Daily consumption increased exponentially for both groups (0.8 to 50–60 cal/day/larva between 7 and 30 days posthatch). Weight specific consumption (WSC) decreased initially and then increased for both groups. A mean WSC of 58% (range of 24–83%) was found for the combined SC and HC groups. Food conversion ratio, growth efficiency, caloric efficiency, and productive protein values were similar for striped bass and hybrid larvae.     

Texture and Flavor of Hybrid Striped Bass Fed Soybean Meal Diets

Baked fillets from hybrid striped bass (Morone saxatilis x M. chrysops) fed varying amounts of soybean meal and raised in ponds or tanks were evaluated for flavor and texture. Using a triangle test, panelists were able to discriminate between fillets from fish fed soybean meal in the diet as compared to fillets from fish fed only fish meal with respect to flavor and texture in most comparisons. In paired comparison tests, panelists described fillets from fish fed soybean meal as less dry or tough compared to fish-meal-fed fish. In addition, panelists were able to discriminate between fillets from fish raised in ponds compared to those raised in tanks, regardless of diet. However, in a limited test, panelists found no differences in the acceptability of fillets with respect to flavor and texture. Data showed that soybean meal in the diet of hybrid striped bass had a significant discernible effect on flavor and texture of fillets, but this effect was not important in acceptability of the fillets.     

杂交条纹鲈苗种培育技术试验

根据对引进的美国杂交条纹鲈的生长发育需求及生理生态要求和食性，应用我国池塘精养技术，肥水培育苗种，进行调控水质，培养天然饵料，精心投喂，科学管理，经1年饲养管理，共出塘鱼种26000余尾，平均全长达14．0cm，平均尾重31．9g，成活率达22．7％。得出初步的苗种培育技术。     

美国条纹鲈的池塘养殖技术

美国条纹鲈，学名海鲈(Morone saxatilis)．又名美洲狼鲈、条鲈、线鲈、淡水石斑等，隶属于鲈形目，鳍鲈科，狼鲈亚科，是一种溯河性鱼类，为美国的传统养殖鱼类。该鱼生长速度快，对环境的适应性强，尤其是对盐度及水温的适应范围广，适合于在淡水及咸淡水水体中养殖。其肉质细嫩鲜美，营养丰富，可与我国名贵的鳜鱼相媲美。美国     

条纹石鱼旨生物学的初步研究

简单介绍了条纹石鱼旨的形态特征、食性、繁殖习性等生物学。     

Genetic Effects and Estimates for the Heritability of Size in Fingerling Hybrid Striped Bass Reared Indoors

Hybrid striped bass fingerlings were grown in replicated indoor tanks for 42 days to evaluate progeny performance of two growth-related traits. Analysis of variance demonstrated significant differences in length and weight of fingerlings among paternal and maternal half-sib families and high estimates of heritability for dams and sires. Based on significant sire and dam effects and high heritabilities, a substantial portion of the selection differential could be expected to be gained in offspring from selected pure-line parents. As demonstrated by these results, a breeding program could be used to select parental lines that produce faster growing hybrid offspring.     

Lethal Effects of Elevated pH and Ammonia on Early Life Stages of Hybrid Striped Bass

Hybrid striped bass larvae (striped bass, Morone saxatilis, ♀ x white bass, M. chrysops, ♂) are often stocked into fertile culture ponds. High rates of photosynthesis may result in elevated pH which can be lethal to fry and can affect the toxicity of ammonia. Six-hour static toxicity tests were performed on hybrid larvae of various ages to determine the toxicity of elevated pH and the effects of elevated pH on ammonia toxicity. Six-hour mortality threshold pH's with no measurable ammonia were estimated for various age larvae and found to be between pH's 9.8 and 10.2 for D2 (Dl is day of hatch), between 9.0 and 9.4 for D4, between 8.8 and 9.2 for D13, and between 9.2 and 9.4 for D20 fish. The addition of 0.7% NaCl had no effect on the toxicity of elevated pH to D2 or D4 fish but caused a significant reduction in the mortality of Dl3 and D20 fish exposed to high pH. The tolerance to elevated pH decreased as ammonia concentration increased. Sub-lethal un-ionized ammonia concentrations increased the toxicity of elevated pH, suggesting an interaction of pH and un-ionized ammonia toxicity.     

Apparent Problems and Potential Solutions for Production of Fingerling Striped Bass,Morone saxatilis

Data on production of fingerling striped bass, Morone saxatilis, in 103 ponds at 17 hatcheries in 1988 were related to information on management practices and water qualities. Production was highly variable, with a median of 50,000/ha. No survival was evident in 12% of ponds; numbers harvested exceeded 250,000/ ha in 5% of ponds. Best survival resulted when larvae were stocked within 2 days after pond filling was started and at hatcheries with relatively low application rates of fertilizers during the prestocking interval. No survival was evident in ponds with pH >9.0 in the week after stocking. High pH's and probably toxic concentrations of un-ionized ammonia were related to water being in ponds for too long prior to stocking and to high applications of fertilizers. Examination of samples of larvae collected at stocking and the week after stocking documented a problem with swim bladder inflation. When larvae were stocked at D5 or D6 (Dl is day of hatch), inflation success averaged 91%: when stocked at ≥D7. inflation success averaged 60%. Measures proposed to improve production include: (1) Stock larvae prior to the critical period of swim bladder inflation(D4-D5). (2) Start filling ponds as close to stocking as is feasible (filling can be completed after stocking). (3) If the concentration of available nitrogen is low, apply no more than 300 µg/L of nitrogen in the prestocking interval. (4) Add phosphorus as needed, but avoid pH>8.5 until larvae are D14.     

The Cryopreservation of Striped Bass Morone saxatilis Semen

Abstract.— Two experiments were designed to improve upon existing methods for cryopreserving striped bass Morone saxatilis , semen. In the first experiment, two extenders, two cryoprotectant concentrations, and two freezing rates were evaluated on the basis of post-thaw semen motility after 1, 7, and 30 d of storage at −196 C. Semen samples cryopreserved at a freezing rate of −40 C/m resulted in a significantly higher percentage of motile sperm ( P < 0.001) and longer duration of spermatozoa motility ( P < 0.001) than samples cryopreserved at a freezing rate of -30 Chin. Also, the cryoprotectant dimethyl-sulfoxide yielded a significantly higher percentage of motile sperm ( P < 0.001) and longer duration of spermatozoa motility ( P < 0.001) when a 5% concentration was used instead of 7.5%. In the second experiment, the two extenders from Experiment I were re-evaluated and a new extender, which was a modified version of Extender 1, was tested. The samples were cryopreserved at -40 C/min with 5% DMSO and thawed in a 25 C water bath. Spermatozoa motility and fertilization ability were evaluated, and semen cryopreserved in Extender 2 yielded the longest duration of spermatozoa motility ( P < 0.001). the highest percentage of motile sperm ( P < 0.001). and the highest percentage of fertilized eggs ( P < 0.002) in comparison to Extenders I and 3.     

Effects of Dietary Carbohydrate: Lipid Ratio on Growth and Body Composition of Hybrid Striped Bass

A study was conducted to determine the ability of juvenile hybrid striped bass, Morone crysops ♀× M. saxatilis ♂ , to utilize dietary carbohydrate and lipid for energy. Four semipurified diets containing 35% crude protein were formulated to be isocaloric with various levels of dextrin and menhaden fish oil 50 the carbohydrate: lipid ratio (CHO:L) ranged from 2510 to 42:2.5. Diets were fed in triplicate to groups of hybrid striped bass initially averaging 1.5 g/fish in 38 L aquaria receiving a constant supply of hard (> 180 mg/L as CaCO₃) freshwater for a period of eight weeks. Weight gain, feed and protein efficiencies were similar among all dietary groups. Hepatosomatic index (liver weight × 100/body weight), muscle ratio (whole muscle weight × 100/body weight) and condition factor were also similar, while intraperitoneal fat (IPF) ratio (IPF weight × 100/ body weight) was significantly ( P × 0.05) increased as CHO:L decreased. Proximate composition of muscle did not show any effects of diet. However, dry matter and lipid of whole-body increased significantly as CHO:L decreased; conversely whole-body protein was significantly reduced. Moreover, liver glycogen significantly increased as CHO:L decreased. These data indicate hybrid striped bass are able to efficiently utilize carbohydrate for energy; and dietary lipid, which generally caused increased lipid deposition in various tissues, could be partially replaced with carbohydrate to improve fish quality and productivity.     

Seasonal Variations in Fatty Acids of Striped Bass Morone saxatilis

The polyunsaturated fatty acids of the n-3 family associated with fish and fish oils have been shown to have beneficial effects on prevention of heart disease in humans. However, in considering the potential health benefits of fish oil in human health, it is important to realize that the fatty acid composition and total lipid content of fish vary greatly. These variations may be due to species differences or variations within a species due to temperature, diet, developmental stage, sex or seasonal differences. The purpose of the study described here was to determine the effects of season, size class, and sex on the Occurrence of individual fatty acids in striped bass (Morone saxrrtilis). Fish were collected in June, July, August, September, and October. Filets with skin were analyzed for total lipid content. Methyl esters of fatty acids were separated and identified using capillary gas chromatography. Total mean lipid varied from as low as 12% to as high as 30%. There were no significant changes in total crude lipid content due to month collected or sex. However, total lipid content of filets increased significantly (P ≤ 0.05) as size increased. The fatty acids 18:1n–9 and 16:0 made up the majority (62%) of the fatty acids present in any season, size class, or sex. The monounsaturated fatty acids dominated in all fish. There were no significant differences in individual fatty acids due to sex. However, fish size had a significant influence on fatty acid composition. Overall, saturated fatty acids decreased as size increased, while polyunsaturated fatty acids increased or remained constant. There were no significant changes in mean percent saturated or monounsaturated fatty acids with respect to month when controlling for size. However, total percent polyunsaturated fatty acids decreased significantly in October compared to August and September. This overall decrease was due mainly to a decrease in 22:6n–3. Conversely there was a significant increase in 16:11n–9 in October. All other fatty acids remained constant. When data from this study were compared to fatty acid data from the literature, striped bass was not as good a source of 20:5n–3 and 22:61n–3 as sardines, anchovies or mackerel.