Comparative fatty acid composition of eggs from wild and captive black sea bass, Centropristis striata L.

Lipid content, lipid class and fatty acid compositions were determined in eggs from wild and captive black sea bass, Centropristis striata L., from northern (New England) and southern (South Carolina) regions to determine the effects of diet on egg composition and fertilization success. The formulated diets fed to the northern captive (NC) fish were higher in total lipids (22%) compared with the cut fish and squid diet fed to the southern fish (SC; 3.3% lipid) and had a higher relative amount of linoleic acid (LA) and lower relative amounts of docosahexaenoic acid (DHA) and arachidonic acid (AA). These dietary differences were broadly reflected in the egg lipid composition. The LA levels were higher in all lipid classes in eggs of NC fish while AA levels were lower. The DHA was higher in the major polar lipids (PL) (phosphatidylcholine and phosphatidylethanolamine) of SC eggs compared with NC. Compared with wild fish, both captive groups produced eggs with PLs richer in LA and lower in DHA and AA. Over all fish groups, fertilization success was directly correlated with levels of DHA and AA in the PLs and was inversely correlated with LA levels.     

Tolerance of juvenile black sea bass Centropristis striata to acute ammonia and nitrite exposure at various salinities

ABSTRACT:   Experiments were conducted to determine the acute tolerance of juvenile (mean weight ± standard error, 9.9 ± 0.9 g) black sea bass Centropristis striata to environmental un-ionized ammonia-nitrogen (NH₃-N) and nitrite-nitrogen (NO₂-N) exposure at various salinities. Specifically, median lethal concentrations (LC50 values) of NH₃-N and NO₂-N at 24, 48 and 96 h of exposure were determined at salinities of 10, 20 and 30 g/L at 22°C. With the exception of LC50 values determined at 48 h, median lethal concentrations of NH₃-N to black sea bass were not influenced by environmental salinity; 24, 48, and 96 h LC50 values ranged from 0.81 to 0.85, 0.65–0.77, and 0.46–0.54 mg-NH₃-N/L, respectively. In contrast, tolerance of black sea bass to environmental NO₂-N was compromised at reduced salinities. Median lethal concentrations of NO₂-N to fish at 24, 48 and 96 h of exposure ranged from 288.3 to 429.0, 258.4 to 358.8 and 190.0 to 241.9 mg-NO₂-N/L, respectively. Results indicate that while juvenile black sea bass are relatively sensitive to acute NH₃-N exposure, they are highly resistant to NO₂-N exposure.     

Effects of shelter on growth and survival in age-0 black sea bass, Centropristis striata (L.)

Black sea bass Centropristis striata (L.) juveniles were reared in aquaria containing either shelter or no shelter to investigate the effects of shelter on growth and survival. The specific growth rates of juveniles were significantly higher in the sheltered aquaria. With shelter present, the average mortality of juveniles caused by agonistic behaviour was 44% compared with no mortality in the unsheltered aquaria. The results provide evidence that shelter is advantageous for growth, but not survival of black sea bass juveniles under culture conditions.     

The effects of temperature on sex differentiation and growth of black sea bass (Centropristis striata L.)

To examine the effects of temperature on sex differentiation in the black sea bass ( Centropristis striata L.), a protogynous hermaphrodite, juveniles (∼0.5 g) were cultured in recirculating systems at 17, 21 or 25 °C. Growth was assessed at 155, 182, 241 and 275 days post hatch and sex differentiation was determined histologically. No differences were found in the sex ratios of fish reared at different temperatures, but only 55–64% developed as females. Growth was significantly greater in males across all temperature treatments. These results suggest that black sea bass exhibit sexually dimorphic growth patterns and that female-specific sex determination can be disrupted in culture.     

Light intensity effects on early life stages of black sea bass, Centropristis striata (Linnaeus 1758)

The effects of four light intensities on growth and survival of first‐feeding stage black sea bass larvae Centropristis striata were investigated in a controlled‐environment laboratory. Fertilized eggs, obtained from LHRHa‐induced spawning of captive broodstock, were stocked (72 eggs L^?1) into twenty 15 L black tanks under light intensities of 100, 500, 1000 and 1500 lx, with five replicate tanks per treatment. The photoperiod was 12L:12D, the temperature was 20°C and the salinity was 35 g L^?1. Larvae were fed rotifers Brachionus rotundiformis from day 2 post‐hatching (d 2ph) at 5–10 rotifers mL^?1. Microalgae Nannochloropis oculata and Isochrysis sp. were added (1:1) daily to maintain a density of 300 000 cells mL^?1. Hatching success and larval growth and survival from d 2ph through d 15ph were monitored. Hatching success was 28–38% under all light intensities, and notochord length at hatching ranged from 2.8 to 3.0 mm, with no significant differences among treatments. By d 15ph, growth (mg wet weight) was significantly higher in the 1000 lx (0.914) and 1500 lx treatments (0.892) than in 100 lx (0.483), and a highly significant trend (P<0.01) towards increased survival with increasing light intensities was observed, from 1.3% at 100 lx to 13.9% at 1500 lx. Higher light intensities within the range of 100–1500 lx improved growth and survival of early larval black sea bass, suggesting that even higher light intensities may improve culture performance. This is consistent with conditions in shallow, near‐shore locations where eggs and larvae are distributed in nature.     

Effect of dietary lipid level on juvenile black sea bass Centropristis striata fed two protein sources

A 10-week feeding trial was conducted with juvenile black sea bass Centropristis striata fed isonitrogenous diets (46% CP) with four lipid levels (7, 10, 13 and 16%) to identify dietary lipid levels supporting maximum weight gain and efficiency. Menhaden fish meal (FM) and animal protein concentrate (APC) were used in a 2×4 factorial experiment to evaluate effects of protein quality and lipid level on production. Weight gain, thermal growth coefficient, protein and energy retention, proximate composition and hepatic indices were evaluated. Weight gain was higher (P<0.05) in FM treatments and no protein sparing effect was observed. All growth, efficiency and retention parameters, except apparent net protein utilization (ANPU) among FM diets, were independent of dietary lipid. Based on proximate composition, diets should be restricted to no more than 13% lipid in 46% CP diet, and can be reduced to 7% without loss of growth and efficiency. Second order polynomial regressions on ANPU indicated 10–12% dietary lipid in a 46% CP diet is appropriate depending on protein quality. Reducing dietary lipid in current commercial feeds fed to black sea bass could represent a substantial cost savings in feed production.     

A comparison of human chorionic gonadotropin and luteinizing hormone releasing hormone analogue for ovulation induction in black sea bass Centropristis striata (Linnaeus, 1758)

Mature black sea bass, Centropristis striata L. (200–800 g), were captured in coastal South Carolina during the spawning season and administered hormones for ovulation induction and strip spawning. During both study years, control groups of females were incorporated into the study design and administered sham injections containing physiological saline solution. In 2004, females received a single intramuscular injection of human chorionic gonadotropin (hCG) (330 IU kg⁻¹) (n=8) or two injections of hCG at 24‐h intervals (n=8). In 2005, females received a single injection of hCG (n=10) or an analogue of luteinizing hormone releasing hormone (LHRHa) (n=10). In 2004, all fish administered a single dose of hCG ovulated at least once. Six fish ovulated on two consecutive days and one fish ovulated on 3 days consecutively. In contrast, six of eight fish receiving two doses of hCG ovulated once, five ovulated on 2 days successively and three fish ovulated 3 days in succession. Of the fish that spawned, no differences were found in any reproductive parameters. In 2005, all fish administered hCG or LHRHa ovulated at least once. Three fish administered hCG ovulated twice, four fish ovulated on three consecutive days and one fish 4 days successively. All fish administered LHRHa spawned at least twice, six fish ovulated thrice and three fish ovulated 4 days, successively. A significant difference in fertility was found between hCG (75.6±11.4%) and LHRHa (55.6±27.4%). The results of this study indicate that both hCG and LHRHa are effective for ovulation induction in prespawning black sea bass.     

The use of clove oil, metomidate, tricaine methanesulphonate and 2-phenoxyethanol for inducing anaesthesia and their effect on the cortisol stress response in black sea bass (Centropristis striata L.)

Juvenile and adult black sea bass (Centropristis striata L.) were exposed to various concentrations of four anaesthetics to determine practical dosages for handling as well as for procedures such as bleeding, ovarian biopsy or tag implantation. In experiment 1, juveniles exposed to either 2.0 mg L^?1 metomidate, 15 mg L^?1 clove oil, 70 mg L^?1 tricaine methanesulphonate (TMS) or 200 mg L^?1 2‐phenoxyethanol (2‐PE) reached stage II of anaesthesia in 3–5 min and could be handled for weighing and measuring. All fish had completed recovery to stage III within 6 min. In experiment 2, the established concentrations of each anaesthetic were tested on juveniles to determine their ability to prevent a reflex to a subcutaneous needle puncture. All of the fish exposed to clove oil (20 mg L^?1) and 40% of the TMS‐treated (70 mg L^?1) fish reacted while none of the fish anaesthetized in metomidate (2.0 mg L^?1) or 2‐PE (200 mg L^?1) responded to the needle puncture. In experiment 3, metomidate (5.0 mg L^?1), clove oil (30 mg L^?1) TMS (125 mg L^?1) or 2‐PE (300 mg L^?1) were all effective for performing an ovarian biopsy or tag implantation on adults. In experiment 4, TMS (125 mg L^?1) exacerbated the cortisol response to a short handling stressor during a 30 min exposure. Fish anaesthetized in 2‐PE (300 mg L^?1), metomidate (5.0 mg L^?1) or clove oil (40 mg L^?1) had increased cortisol levels associated with the handling stressor but there were no further increases during the remainder of the experimental period. The results demonstrate that these anaesthetics are effective for sedation and anaesthesia of black sea bass and that the best choice is dependant upon the procedures to be performed.     

Effects of dietary protein and lipid levels on growth performance and body composition of black sea bass Centropristis striata (Linnaeus 1758) during grow-out in a pilot-scale marine recirculating system

The influence of four formulated practical diets, with different protein and lipid levels, on the growth and body composition of black sea bass ( Centropristis striata L.) pre-adults was evaluated in a pilot-scale marine recirculating system. Four test diets were prepared with a combination of two protein levels (44% and 54%) and two lipid levels (10% and 15%). The diets were as follows: low protein and low lipid (LP:LL; 44:10), low protein and high lipid (LP:HL; 44:15), high protein and low lipid (HP:LL; 54:10) and high protein and high lipid (HP:HL; 54:15). Fish (mean weight=75.5 g) were fed the respective diets for 90 days. For fish fed LP:HL, body weight gain was significantly ( P <0.05) higher than fish fed LP:LL. Increasing the protein level from 44% to 54% did not produce a significant effect on weight gain at high lipid level. A significant ( P <0.01) interactive effect between dietary protein and lipid levels on the growth and feed utilization was observed. Total lipid content in the whole body, muscle and liver was significantly affected by the dietary lipid levels. The results suggested that a combination of 44% dietary protein and 15% lipid was optimal for the growth of black sea bass.     

Dispersal of black sea bass (Centropristis striata) larvae on the southeast U.S. continental shelf: results of a coupled vertical larval behavior – 3D circulation model

In the marine environment, pelagic dispersal is important for determining the distribution and abundance of populations, as well as providing connections among populations. Estimates of larval dispersal from spawning grounds are important to determining temporal and spatial patterns in recruitment that may have significant influences on the dynamics of the population. We present a case study of the dispersal of Centropristis striata (black sea bass) larvae on the southeast U.S. continental shelf. We use a coupled larval behavior – 3D circulation model to compare the effects of the timing and location of spawning against that of larval vertical migration on larval dispersal. Using the results of field data on larval vertical distributions, we compare the dispersal of virtual 'larvae' which have ontogenetic changes in vertical behavior with that of particles fixed near the surface and near the bottom. Larvae were released at potential spawning sites four times throughout the spawning season (February through May) for 3 yr (2002–04) and tracked for the assumed larval duration (from 27 to 37 days including the egg stage). Results indicate that adult behavior, in the form of spawning time and location, may be more important than larval vertical behavior in determining larval dispersal on the inner- and mid- continental shelves of this region.     

Comparison of Four Commercial Diets and Three Feeding Rates for Black Sea Bass,Centropristis striata,Fingerlings

Abstract

A new demand for live black sea bass, Centropristis striata L., is emerging in the fish markets of the northeast United States and Canada. Aquaculturists need to know suitable commercial diets and feeding rates for growing black sea bass to increase profitability. In these experiments, four commercial diets and three feeding rates were compared for juvenile black sea bass (0.8-1.3 g). The diet experiment compared growth rates for fish fed four commercial diets, Rangen Trout and Salmon Starter (R), Nelson and Son's Silver Cup Trout Crumbles (SCT), Nelson and Son's Silver Cup Salmon Crumbles (SCS), and Zeigler Salmon Starter (Z). The feeding rate experiment compared growth rates for fish fed Zeigler Salmon Starter, at 2.5%, 5.0%, and 7.5% levels (dry weight of food/wet weight of fish). At the end of the diet experiment (18 weeks), Tukey's studentized range test (? = 0.05) showed that fish fed diet Z (14.5±0.92 g) were significantly larger than fish fed diet R (11.4±0.93 g). Diets Z and R both produced significantly larger fish than diets SCS (7.3±0.85 g) and SCT (4.5±0.29 g). At the end of the feeding rate experiment (10 weeks), Duncan's multiple range test (? = 0.05) showed that fish fed a 7.5% (4.61±0.24 g) rate and a 5.0% (4.49±0.24 g) rate were not significantly different in weight. Both of these treatments produced significantly larger fish than a feeding rate of 2.5% (3.59+0.21 g).     

Preliminary investigations on the effects of dietary lipid on the spawning performance and egg quality of black sea bass Centropristis striata L

Adult black sea bass Centropristis striata broodstock ( N =162) were fed three different dietary treatments: two commercially prepared diets with 45% protein and two different lipid levels (12% and 20%) (diets 1 and 2), and a diet of frozen Atlantic silversides Menidia menidia (SS, diet 3). Broodstock were held under controlled photothermal conditions and induced to spawn with an LHRHa pellet (72 μg kg⁻¹ bw). Dietary lipid had pronounced effects on spawning performance and egg quality. Diet 3 (SS) produced a significantly ( P <0.05) higher fertilization success (22.4%) than diets 1 (0.6%) and 2 (4.8%). The hatching success of fertilized eggs was similar in all diets (range=40–58.6%), but only two spawns from diet 1 (12% lipid) yielded viable yolk-sac larvae (YSL). Diet 3 (SS) also produced significantly more YSL per female (21.8 × 10³) than the diet 1 (0.3 × 10³). Eggs from diet 3 (SS) contained a significantly greater proportion of n-3 series fatty acids, with docosahexaenoic acid (DHA) as the largest fraction. Eggs from commercially prepared dietary treatments contained significantly more n-6 fatty acids. The poor spawning performance of fish fed diet 1 (12% lipid) may be related to higher levels of linoleic acid and lower levels of DHA in the diet.     

Phosphorus requirement of European sea bass (Dicentrarchus labrax L.) juveniles

A growth trial was conducted to estimate the phosphorus requirement of European sea bass juveniles. Six experimental isonitrogenous and isoenergetic semi‐purified diets (casein based) were formulated to contain 0.48%, 0.65%, 0.77%, 0.86%, 1.05% and 1.25% phosphorus (diets D1, D2, D3, D4, D5 and D6 respectively). Dicalcium phosphate was used as dietary phosphorus source. Twelve groups of 25 fish of 10 g initial body weight were allocated to 55‐L tanks in a thermoregulated water recirculating system. Each experimental diet was assigned to duplicate groups of these fish. The trial lasted for 10 weeks and fish were fed two times a day, 6 days a week, to apparent visual satiation. At the end of the trial, final weight of fish fed diet D1 was significantly lower than that of the other groups, except of fish fed diet D4. Mortality of fish fed diet D1 was significantly higher than that of fish fed the other diets, except for diet D6. Feed efficiency and protein efficiency ratios were significantly lower with diet D1 than with the other diets. Nitrogen retention (% nitrogen intake) of fish fed diet D1 was significantly lower than in the other groups, except that of fish fed diet D4. Energy retention (% energy intake) was not significantly different among groups. At the end of the trial there were no differences in whole body composition among groups. Whole body phosphorus content averaged 0.72% (on a fresh weight basis) and was not significantly affected by dietary phosphorus content. Phosphorus retention averaged 6.1 g kg^?1 weight gain and was not significantly different among groups. Phosphorus retention (% phosphorus intake) was significantly higher in fish fed diets D2 and D3 than in fish fed higher dietary phosphorus levels. Expressed per unit body weight per day, phosphorus retention was not significantly different among groups fed diets D2 to D6, while phosphorus losses linearly increased with dietary phosphorus intake. Results of this trial indicate that the phosphorus requirement of sea bass juveniles was satisfied with a diet containing 0.65% of phosphorus.     

Information on Selected Water Quality Characteristics for the Production of Black Sea Bass,Centropristis striata,Juveniles

Abstract

Recent interest in the culture of black sea bass, Centropristis striata, has led to questions regarding the environmental requirements of this species for economically-viable production. Here, we present the results of short-term laboratory studies on ammonia toxicity, nitrite toxicity and oxygen consumption rates. Fifty percent of the juveniles died when exposed to 0.7-0.8 mg/L un-ionized ammonia-N for 24 hours (25°C, 23 g/L salinity). All exposed fish survived exposure to ≤ 0.6 mg/L un-ionized ammonia-N for 10 days. Black sea bass juveniles survived 24-hours exposure to 250 mg/L nitrite-N when exposed in 12 or 20 g/L salinity. Fish exposed for 24 hours to nitrite in 35 g/L salinity died when exposed to 250 mg/L nitrite-N, but survived exposure to 100 g/L nitrite-N. All fish exposed to 50 mg/L nitrite-N for 10 days survived (salinities of 12, 20 and 35 g/L). Mean oxygen consumption rate was 0.09 mg/hour/g (25°C). Fish weight significantly affected oxygen consumption rate with larger fish consuming less oxygen per unit time on a weight-specific basis. No treatment effect was observed due to salinity or dissolved oxygen concentration. The information reported here in combination with previous reports provides insight into the environmental requirements of black sea bass culture.     

Effect of lordosis on the swimming performance of juvenile sea bass (Dicentrarchus labrax L.)

The critical swimming speed (U_crit, cm s⁻¹) value of normal juvenile sea bass (Dicentrarchus labrax) (64.7±6.33) was significantly higher than that of fish with lordosis (60.3±6.66) (P<0.05). Both normal fish and those with lordosis showed increased endurance with increasing length during exercise at a fixed water velocity of 50 cm s⁻¹. This speed was used to investigate the separation possibility of deformed specimen from the normal developed fish based on their swimming performance, and 28% separation was achieved without losing any normal fish by the end of the 10th minute. To achieve a better separation of the deformities from the normal, first grading of the juveniles and then a swimming endurance test is advised.     

Influence of tank volume on vitellogenesis and spawning performances in sea bass Dicentrarchus labrax L.

Sea bass, Dicentrarchus labrax (mean weight: 748±13 g), were maintained before and during vitellogenesis in 1, 3, 8, 16 and 32 m³ tanks, and then they were transferred to 2 m³ tanks, for the spawning season. During the first 2 months of the experiment, the growth rates were significantly lower in smaller tanks (1 m³). In August, the oocyte diameters were significantly lower in smaller tanks (1, 3 and 8 m³) than in larger (16–32 m³) tanks. At the end of the experiment, the fish mean weight in the 1 m³ tanks was significantly lower than in the 3 m³ tanks, but oocyte diameters and plasma oestradiol concentrations were not significantly different between the volumes. This shows a longer acclimation requirement in smaller volume rearing. Although all the females had not spawned, one spawn at least was collected in each volume. The variation in conditioning volume has not blocked the spawning process. The qualitative and quantitative characteristics of spawns were not significantly different between volumes. The conditioning volume of 3 m³ seems to be a minimal volume required to obtain good reproduction of sea bass.     

利用棉籽浓缩蛋白替代条纹锯鮨饲料鱼粉的潜力

通过10周生长实验评价了利用棉籽浓缩蛋白替代条纹锯鮨饲料鱼粉的潜力。采用单因素实验设计,设4个鱼粉替代水平。对照饲料(C)中鱼粉含量为35%,通过添加棉籽浓缩蛋白分别替代饲料C中鱼粉的40%(R40)、60%(R60)和80%(R80)。每个处理设3个重复。实验鱼初始体质量为(29.5±0.5) g。实验期间,每天分2次按饱食量投喂实验饲料。结果发现,利用棉籽浓缩蛋白替代饲料鱼粉对鱼摄食、生长、饲料利用效率、鱼体组成和养殖废物(氮、磷和碳)排放量无显著影响,但单位鱼产量鱼粉消耗量(RCP)随饲料鱼粉含量下降而降低。基于生长、饲料成本、饲料利用效率、对环境的影响和RCP进行综合分析,研究表明,投喂饲料R80时的养殖效益与投喂饲料R40和R60时存在较大差异,通过添加棉籽浓缩蛋白可将条纹锯鮨饲料鱼粉含量降低至7%。