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Along the Atlantic coast black sea bass occur from the Gulf of Maine to Florida and support important commercial and recreational fisheries. Interest in commercial production of black sea bass has increased in recent years due to high demand and limited seasonable availability. Efforts towards large-scale production have been hampered by a high incidence of early larval mortality. Two of the most important environmental variables affecting hatchery production of marine finfish larvae are temperature and salinity. In the wild, larval black sea bass are found in waters with temperatures of 12–24 C and salinity levels of 30–35 ppt. Studies were conducted to define the temperature and salinity ranges that support growth and development of black sea bass during early life stages. Three developmental phases were investigated: 1) fertilization to hatch: 2) hatch through yolk sac absorption: and 3) during the initial exogenous feeding stage (5–14 days post hatch: DPH). Fertilized eggs were obtained by manual spawning of fish following administration of LHRHa. Fertilized eggs were transferred to 300-mL glass Petri dishes or 500-mL beakers to assess the effects of salinity and temperature through hatch and yolk sac absorption, respectively. To determine environmental effects on growth and survival during initial exogenous feeding 400 actively feeding larvae were cultured in green water and fed enriched rotifers for a 9-d period. For investigation of the effect of salinity, sea water (35 ppt) was diluted gradually to 15, 20, 25, and 30 ppt and maintained at 21 C. For examination of the effect of temperature, seawater was adjusted from 21 C to 12, 15, 21, 27, or 30 C at a rate of 3 C/h. No eggs hatched at 12 C or when salinity was maintained at 0 or 5 ppt. Hatching was uniformly high (≥ 85%) at temperatures between 15 and 27 C and at salinities ≥ 15 ppt. Survival through yolk sac absorption was greatest at temperatures between 18 and 27 C and at salinities ≥ 20 ppt. Survival through first feeding stage was highest at temperatures ≥ 18 C and 30 ppt salinity. Larval growth through first feeding was not significantly affected by salinity level but did increase with rearing temperature. The results indicate that survival and development of black sea bass during early life stages are most favorable at temperatures >18 C with salinity levels approaching full strength seawater.

The objective of this project was to determine if a low-cost biosolar filter system, based on microbial mats and fluidized sand filters, could be used for a greenhouse recirculating black sea bass ( Centropristis striata ) mariculture project. Microbial mats are stratified microbial communities, composed of a complex of bacteria and dominated by photoautotrophic cyanobacteria, which can transform nitrogenous wastes into cellular protein and rapidly metabolize other fish wastes. The microbial mats also provided an excess of oxygen for the nitrifying bacteria on the fluidized sand filters, providing favorable conditions for ammonia removal. The filter system was altered after it was found that microbial mat surfaces became covered with fish wastes, which resulted in oxygen-production decreases and ammonia-concentration increases. The modification included delivering the fish wastewater under the mats, rather than on the surface, thus depositing solids beneath the photosynthetic surfaces. Instead of pellets, live tilapia ( Oreochromis sp.) juveniles were used as food which decreased the amount of solid wastes produced. Water and sludge from the fish tank were drained by gravity from the bottom of the fish tanks into the microbial mat trays at a rate of 7 l/min. Stable functioning mats provided high oxygen levels, supported the nitrifying bacteria and removed wastes produced by the black sea bass. Oxygen concentrations ranged from 6 to 10 mg/l and total ammonia concentrations remained below 1 mg/l. During the 9th month there was a steady fish growth, little buildup of solids and the fish tank remained clear. The mean weights of the 15 fishes increased from 161±45 to 215±72 g, and to 337±99 g after 2, 4, and 9 months, respectively.

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 consumi...

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 black sea bass Centropristis striata has recently gained popularity in the live seafood markets of the northeastern United States. Fish farmers need instruction on optimizing environmental parameters for the growth of black sea bass. In this study, optimal temperature and salinity were determined experimentally for the growth of juvenile black sea bass (initial mean weight, ∼9.2 g). The temperature experiment compared growth at temperatures of 15, 20, 25, and 30°C; the salinity experiment compared growth at 10, 20, and 30‰ salinities. Both of these experiments were performed in closed aquaria. At the end of the temperature experiment (6 weeks), Tukey's Studentized range test (α = 0.05) showed that fish reared at 25°C were significantly larger than those reared at 20°C and 30°C. All of these temperatures produced significantly larger fish than did the 15°C treatment. At the end of the salinity experiment (12 weeks), Tukey's Studentized range test (α = 0.05) showed that salinities of 20‰ and 30...

Black sea bass (Centropristis striata) are territorial fish and cannibalism is a concern when rearing juveniles in intensive systems. Three studies were conducted to provide information for development of suitable tank nursery systems for juvenile black sea bass (3.6–4.5 cm; 0.8–1.7 g). Studies were performed at the Marine Resources Research Institute, Charleston, SC, using 1.5-m diameter × 0.8 m deep tanks connected to recirculating seawater systems. The studies examined growth and survival at different stocking densities, selection and utilization of habitats, and, effects of water velocity on positioning and movement of fish. In study 1, fish were stocked at biomass densities of 126.7, 253.3, and 506.7 Wm3 and reared for 56 days with no habitats. No difference in growth was detected although fish reared at the lower densities had significantly lower mortality (mean 7.9%) as compared to those at the highest density (28.0%). At the highest density, cannibalism appeared to be a substantial cause of mortality. In study 2, three habitat types were used, (1) two-tier structure constructed from plastic grating with 15 mm square openings (volume = 0.015 m3); (2) PVC pipe bundle (volume = 0.004 m3); (3) rock aggregate (volume = 0.008 m3). Of the habitats, the most utilized habitat (62.9%) was the two-tier layered structure that allowed movement in all directions. The next utilized type was the pipe bundle (25.6%) with the openings inhabited by the largest juveniles in each tank. Overall, a mean of 18.2% of the fish were observed using habitats. Study 3 examined water velocities ranging from 0.01 to 0.12 m/sec. Most fish became concentrated in the tank bottom area having a water velocity in the range of 0.040.09 m/sec. At these velocities there were few aggressive interactions. Smaller fish inhabited the areas outside this velocity range. At the higher velocities, the small fish swam vigorously to maintain their position in the water column. At the low velocities, sporadic incursions of larger fish occurred presumably to attempt to cannibalize or to defend territory. Results from these studies help to define characteristics of nursery systems for rearing juvenile black sea bass.

A study to determine the effects of four stocking densities on growth and feed utilization of wild-caught black sea bass Centropristis striata was conducted in a pilot-scale recirculating tank system. The outdoor system consisted of 12 insulated fiberglass tanks (dia. = 1.85 m; vol. = 2.17 m3) supported by biological filters, UV sterilizers, and heat pumps. Subadults (N= 525; ×± SD = 249 ± 16.8 g) were stocked at densities of 4.6 fish/m3 (1.18 kg/m3), 16 fish/ m3 (3.91 kg/m3), 25.3 fish/m3 (6.83 kg/m3), and 36 fish/m3 (7.95 kg1m3), with three replicate tanks per treatment. Fish were grown under 35 ppt salinity, 21-25 C, and under ambient photoperiod conditions. A commercial flounder diet containing 50% protein and 12% lipid was hand-fed twice daily to satiation for 201 d. Mean (range) total ammonia-nitrogen, 0.61 (0-2.1) mg/L, nitrite-nitrogen, 0.77 (0.04-3.6) mg/L, and nitrate-nitrogen 40.1 (0-306) mg/L were significantly higher (P 0.05) in growth (RGR = 196.8-243.1%; DWG = 2.55-2.83 g/d; and SGR = 0.55-0.61%/d), coefficient of variation of body weight (CwtV., = 0.24-0.25), condition factor (K = 2.2-2.4), feed consumption (FC = 1.45-1.65%/d), and feed conversion ratio (FCR = 1.45-1.52) among stocking densities. Final biomass densities on day 201 reached 3.48, 12.0, 21.1, and 27.2 kg/m3 at stocking densities of 4.6, 16, 25.3, and 36 fish/m3, respectively. Survival (83.8-99.1%) did not differ among treatments. Apparent net protein retention (ANPR) was significantly higher (P 0.05) in apparent net energy retention (ANER = 55.9-59.1 %) among stocking densities. Final whole body protein (15.3-16.3%) and lipid (23.1-26.4%) levels did not differ significantly (P > 0.05) among treatments. The results demonstrated that growth, survival, and feed utilization were not impaired under stocking densities ranging from 4.6-36 fish/m3 (3.48-27.2 kg/m3), despite a slight reduction in water quality at the higher densities. In addition, growth variation and final whole body protein and lipid levels were not influenced by these densities. The results suggest that black sea bass are tolerant of crowding and moderate variations in water quality during intensive culture in recirculating tank systems and that higher stocking densities are possible.

The black sea bass is a high-value marine serranid and is a prime candidate for intensive cultivation. Reliable methods for controlled spawning are needed to accelerate the development of hatchery technologies that result in mass production of healthy juveniles. During 1998–2001, spawning studies were conducted at The University of North Carolina at Wilmington (UNCW) and at the South Carolina Department of Natural Resources (SCDNR), Charleston, using pelleted luteinizing hormone releasing hormone analogue (LHRH-a). From April through July 2001, 28 vitellogenic-stage females, with mean oocyte diameters (MOD) ranging from 277–448 μm, were implanted with a 95% cholesterol-5% cellulose pellet containing LHRH-a (-50 μg/kg body wt) at UNCW. In 10 individual spawning trials, females with MOD of 305–448 μm and maximum oocyte diameter × 475 μm spawned volitionally beginning 2–3 d post-implantation (PI) and continued spawning over an average of 1.9 d (range = 1–4 d). Individual females released a mean total of 149,000 eggs (117,000 eggs/kg) with a mean buoyancy rate of 40.5% (floaters). Fertilization and hatching rates were 98% and 27.2% of floaters, respectively, yielding 14,600 yolksac larvae/female (12,600 yolksac larvae/kg body wt), and overall egg viability averaged 8.9%. In eight group spawning trials (2–3 females/group), average performance of females, including fecundity (103,800 eggs/female; 105,500 eggs/kg body wt), buoyancy rate (42.5%), fertilization and hatching rates (97.7% and 24.3% of floaters), numbers of yolksac larvae produced (10,900 yolksac larvae/female; 10,100 yolksac larvae/kg body wt), and overall egg viability (10.6%) was comparable to what was seen in individual spawning trials. From 1998–2000, a total of 58 vitellogenic stage (70% of oocytes 500 pm) females were implanted with pelleted LHRH-a (-50 μg/kg body wt) in nine group spawning trials (2–19 females/group) at SCDNR. Volitional spawning typically began 18–42 h PI and recurred every 1–3 d for an average duration of 9 d. Female groups released a mean of 560,000 eggs (84,000/female; 132,000/kg body wt) over the spawning period, with mean buoyancy rate of 25.7% floaters. Fertilization and hatching rates were 17.7% and 11.6 % of floaters, respectively, yielding 4,300 yolksac larvae/female (4,600 yolksac larvae/kg body wt). Overall egg viability was 2.9%. Captive wild-caught black sea bass were induced to undergo repetitive volitional spawning by implantation of pelleted-LHRH-a, consistent with a multiple clutch group synchronous pattern of ovarian development. Group spawning appears to be a practical way to compensate for variable fecundity and egg viability of individual females. Research is needed to identify optimum hormone treatments and eligibility requirements.

The black sea bass, Centropristis striata, is a potential candidate for commercial aquaculture in the United States. One of the most significant constraints limiting commercial production of black sea bass is the lack of a reliable supply of eggs and larvae. A narrow window of annual spawning prevents year-round availability of juveniles for grow out. The present study reports on the use of photoperiod manipulation to alter the timing of spawning in C. striata and increase availability of larvae. Adult black sea bass were maintained under a simulated natural (SNP) or an accelerated long day (ALD) photoperiod regimen. Water temperature was adjusted from 14 to 20 °C to correspond to seasonal changes in daylength. Reproductive development was monitored by histological analysis of gonadal biopsies and plasma levels of sex steroids (estradiol-17β, testosterone and 11-ketotestosterone). Females in both regimens were induced to spawn by implantation of 25 μg luteinizing hormone-releasing hormone analogue (LHRHa) when follicle diameters exceeded 500 μm. Acceleration of the photoperiod advanced the annual cycle of circulating gonadal steroids in both sexes without altering the profile. The onset of spermiation in males was unaffected by photoperiod manipulation, but follicle growth and spawning in females were advanced approximately 2 months by exposure to the ALD regimen. Of interest, the ALD photoperiod regimen accelerated the time frame of sexual succession from female to male without reducing the mean volume of eggs produced per female. These findings suggest that photoperiod manipulation can be used to alter the timing of reproduction in black sea bass and increase the supply of eggs for commercial aquaculture.

During 1978–1998, 80,558 black sea bass Centropristis striata were caught with blackfish and chevron traps off eastern Florida, Georgia, South Carolina, and North Carolina at depths ranging from 9 to 55 m. Black sea bass were found to live for at least 10 years, but most were ages 1–5. There were latitudinal differences in the size at age, significantly larger size at age occurring in the southern segment (31°20′N to 32°40′N) than in the northern segment (32°41′N to 34°00′N). Males were found in all size-classes and age-classes and were most frequently encountered at sizes greater than 220 mm standard length (SL) and greater than age 4 in the southern segment and at sizes greater than 240 mm SL and greater than age 5 in the northern segment. Sexual transition and maturity of females occurred at smaller sizes and younger ages in the southern segment than in the northern segment. Probit analysis indicated that between 1978–1982 and 1987–1998 the size at 50% maturity (L 50) for females fell from 137...

Subtidal accumulations of oyster shell have been largely overlooked as essential habitat for estuarine nekton. In southeastern U.S. estuaries, where oyster reef development is mostly confined to the intertidal zone, eastern oyster (Crassostrea virginica) shell covered bottoms are often the only significant source of hard subtidal structure. We characterized and quantified nekton use of submerged shell rubble bottoms, and compared it to use of intertidal reefs and other subtidal bottoms in the North Inlet estuary, South Carolina. Replicate trays (0.8 m2) filled with shell rubble were deployed in shallow salt marsh creeks, and were retrieved after soak times of 1 to 25 days from May 1998 to March 2000. Thirty six species of fishes, representing 21 families, were identified from the 455 tray collections. Water temperature, salinity, soak time and the presence of a shell substrate all affected the catch of fishes in the trays. Catches during the warmer months were two to five times greater than those during the winter. Fishes were present in 98% of the trays with an overall average of 5.7 fish m−2. The assemblage was numerically dominated by small resident species including naked goby (Gobiosoma bose), oyster toadfish (Opsanus tau), and crested blenny (Hypleurochilus geminatus). Transient species accounted for 23% of all individuals and 62% of the total biomass due to the presence of relatively large sheepshead (Archosargus probatocephalus) and black sea bass (Centropristis striata). Both the transient and resident species displayed distinct periods of recruitment and rapid growth from April to October. Lower abundances of juvenile gobies and blennies during 1998 were attributed to long periods of depressed salinity caused by high rainfall associated with El Nino conditions in spring. Crabs and shrimps, which were often more abundant than the fishes, accounted for comparable biomass in the tray collections. In comparisons of subtidal tray and trawl catches, trays yielded 10 to 1,000 fold higher densities of some demersal fish groups. Comparisons of intertidal and subtidal gear catches indicated that many species remain in the subtidal shell bottom at all stages of the tide. This study suggests that subtidal shell bottom may be essential fish habitat for juvenile seabass, groupers, and snappers and that it may be the primary habitat for a diverse assemblage of ecologically important resident fishes and crustaceans. Given the high levels of nekton use and the areal extent of oyster shell bottoms in eastern U.S. and Gulf estuaries, increased attention to protection and restoration of these areas appears justified.

The effects of four practical diets on growth, feed utilization, and body composition of wild-caught juvenile and subadult black sea bass Centropristis striata (316 ± 113 g =±± SD) were compared for 221 d in a recirculating tank system consisting of 12 2,660-L tanks. Salinity averaged 33.5 ppt and temperature averaged 20.9 C but vaned from 12 to 27.1 C. Diets differed in crude protein (CP) and crude lipid (CL) as follows: 1) low CP (44.0%), low CL (11.4%) trout diet; 2) low CP (44.8%), high CL (15.0%) trout diet; 3) midlevel CP (47.9%), midlevel CL (12.8%) Bounder diet; and 4) high CP (53.9%), high CL (15.1%) marine finfish diet. Energy: protein ratios (E: P) were 44.6, 45.3, 41.8, and 39.1 W/g. Survival to 221 d on all diets was 100%. Significant (P < 0.05) differences in growth rates were observed among diets. Final weights were higher for midlevel and high CP diets 3 and 4 (1,051 and 1,013 g) than for low CP diet 1 (873 g). Relative growth rate (RGR, % total increase in weight), specific growth rate (SGR, % increase in body weight/d), and daily weight gain (DWG, g/d) were higher for higher CP diets 3 and 4 (RGR = 223 and 221; SGR = 0.53; DWG = 3.28 and 3.16), than for low CP diet 1 (RGR = 181; SGR = 0.47; DWG = 2.54). There were no significant differences between initial and final whole body protein and fiber content among diets. Lipid and gross energy levels significantly increased (P < 0.0001) in all treatments while moisture levels significantly decreased (P < 0.001). Although these differences were not significant, feed conversion ratio (FCR = dry weight fed/wet weight gain) was lower for fish given midlevel CP diet 3 (1.49) and high CP diet 4 (1.52) than for those fed low CP diets 1 and 2 (1.60 and 1.62). Protein efficiency ratios (PER = weight gain/weight protein fed) (1.43 to 1.24), apparent net protein retention (ANPR = weight protein gain/weight protein fed) (20 to 25%), and apparent net energy retention (ANER = energy gain/energy fed) (53.3 to 56.8%) were not significantly different among treatments. The midlevel CP (50%), midlevel CL (12%) diet maximized growth rates and was also significantly less expensive per kg fish weight produced ($1.40) than the high CP diet ($1.94) which produced the second highest growth rates. These results demonstrated that wild-caught black sea bass can be successfully reared in recirculating tanks from juvenile to marketable sizes with high survival and with good feed conversion and growth on commercially prepared diets with a wide range of protein and lipid levels.

Black sea bass fisheries in the Middle Atlantic have traditionally used fish traps without escape vents that required sorting the catch by size after hauling the trap. The need to reduce discard mortality and increase the yield per recruit in sea bass fisheries prompted an investigation into the effectiveness of escape vents in the traps. An array of experimental traps using one of four escape vents openings (sizes of 2.86 cm ×14.6 cm , 3.18 cm ×14.6 cm , 3.49 cm ×14.6 cm , or 3.81 cm ×14.6 cm ) was fished from May to November 1994. Use of escape vents significantly (p 2.86 cm ×14.6 cm , which produced the highest ratio of legal- to sub-legal-sized sea bass. The catch of legal size sea bass was reduced in number by 3% whereas the catch of sub-legal fish was reduced to 72%. Seasonal changes in catch occurred among all vent sizes, which followed the traditional pattern of highest landings in the fall prior to the fishes migration to the outer continental shelf. The use of escape vents should result in relatively small short-term economic losses to fishermen while increasing the efficiency of fishing practices and increasing long-term yields from the fisheries.

In this study, we applied systematic adaptive cluster sampling (SACS) to assess the abundance of black sea bass Centropristis striata on hard bottom habitats in the Mid-Atlantic Bight (MBA; USA). We used a remote underwater video system to obtain video recordings of black sea bass from 25 June to 6 August 2013 within a 25-square nautical mile (nmi2) sampling region. Data in the form of fish counts were collected from video recordings and used to estimate parameters including sample means and population totals of black sea bass for two adaptive cluster sampling estimators and a single systematic sampling estimator. The precision and relative efficiencies of the parameter estimates were also calculated and compared. In total, two adaptive cluster samples were encountered within the sampling region. Sample means and population totals were largest for the systematic sampling (SS) estimator while the adaptive sampling estimators produced parameter estimates with the lowest variances and highest precision. Our results indicated that SACS was more efficient and advantageous with respect to sampling costs [i.e., sampling time (hours) and travel distance (kilometers)] than SS alone for assessing the abundance of clustered populations of C. striata on hard bottom habitats in the MBA.

We cloned two cDNAs for two gonadotropin-releasing hormones, GnRH2 (chicken GnRH-II) and GnRH3 (salmon GnRH), respectively, from the black sea bass (Centropristis striata). Black sea bass are protogynous hermaphroditic teleosts that change from females to males between 2 and 5 years of age. Similar to other GnRH precursors, the precursors of black sea bass GnRH2 and GnRH23 consisted of a signal peptide, decapeptide, a downstream processing site, and a GnRH-associated peptide. Our analyses failed to identify GnRH1. GnRH3 precursor transcript was more widely distributed in a variety of tissues compared with GnRH2. Further examination of GnRH expression and gonadal histology was done in black sea bass from three different size groups: small (11.4–44.1 g), medium (179.4–352.2 g) and large (393.8–607.3 g). Interestingly, GnRH3 expression occurred only in the pituitaries of males in the small and medium groups compared with expression of GnRH2. Future functional studies of the sea bass GnRHs will be valuable in elucidating the potential underlying neuroendocrine mechanisms of black sea bass reproduction and may ultimately contribute to management advances in this commercially important fish.

Black Sea Bass (Centropristis striata) in the mid-Atlantic Bight undertake seasonal cross-shelf movements to occupy inshore rocky reefs and hardbottom habitats between spring and fall. Shelf-wide migrations of this stock are well documented, but movements and home ranges of fish during their inshore residency period have not been described. We tagged 122 Black Sea Bass with acoustic transmitters at a mid-Atlantic reef to estimate home-range size and factors that influence movements (>400 m) at a 46.1-km2 study site between May and November 2003. Activity of Black Sea Bass was greatest and most consistent during summer but declined rapidly in September as water temperatures at the bottom of the seafloor increased on the inner shelf. Black Sea Bass maintained relatively large home ranges that were fish-size invariant but highly variable (13.7–736.4 ha), underscoring the importance of large sample sizes in examination of population-level characteristics of mobile species with complex social interactions. On the basis of observed variations in movement patterns and the size of home ranges, we postulate the existence of groups of conspecifics that exhibit similar space-use behaviors. The group of males released earlier in the tagging period used larger home ranges than the group of males released later in our study. In addition, mean activity levels and the probability of movement among acoustic stations varied among groups of fish in a complex manner that depended on sex. These differences in movement behaviors may increase the vulnerability of male fish to passive fishing gears, further exacerbating variation in exploitation rates for this species among reefs.

The salinity and temperature tolerances of black sea bass Centropristis striata juveniles (46 ± 10.3 mm total length [mean ± SD]) were estimated to assist in decisions concerning location of culture facilities and types of production systems. At 21°C, all exposed fish survived for 7 d in salt concentrations of 10, 20, or 35 g/L. All fish exposed to salt concentrations of 5 g/L died within 3 d. Temperature extremes were estimated after acclimation of fish to 24–25°C. Half of the juveniles exposed to a gradual increase (+0.65°C/d) or decrease (–0.51°C/d) in temperature (at a nominal salt concentration of 20 g/L) were dead when the water temperature reached 33.3°C and 3.7°C, respectively. Results of this study indicate that this species requires saline water at or above a salt concentration of 10 g/L and that it may not be practical to keep black sea bass over winter or over summer in shore-based outdoor facilities located in temperate climates.

Winter mortality has been hypothesized to select for large body size in young-of-the-year (YOY) fishes, yet substantiation of winter mortality and its cause(s) are available for few estuarine or marine species. We examined seasonal length distributions of wild populations of four common marine species, black sea bass (Centropristis striata), tautog (Tautoga onitis), cunner (Tautogolabrus adspersus), and smallmouth flounder (Etropus microstomus), and mortality (i.e., frequency of death), growth, and behavior of their YOY in the laboratory at ambient winter temperatures (mean 7°C, range 2–13°C) during a 135-day period (December 1992 through mid-April 1993) to establish potential causes of their mortality in the field. Young-of-the-year black sea bass experienced 100% mortality when water temperatures decreased to 2–3°C in February, emphasizing the importance of winter emigration from estuaries in this southern species. The low mortality of two labrid species, YOY tautog (14%) and YOY cunner (3%), was consistent with their northern distribution and year-round occurrence in estuarine and nearshore coastal waters. Laboratory mortality of YOY smallmouth flounder (33%) was higher for small (

Northern-stock black sea bass Centropristis striata demonstrated upper and lower median lethal temperatures of 33.6°C and 2.7°C, respectively, when temperatures were increased or decreased at a rate of approximately 0.5°C per day. The temperature for optimal growth was 25.6°C. This work, along with information in the literature, indicates that thermal tolerances and preferences do not differ greatly between the northern and southern stocks of black sea bass.

Although some anglers regularly deflate swim bladders of demersal fishes being released, it is not known whether this practice actually increases postrelease survival of reef fishes. Benefits of deflating the swim bladder of black sea bass Centropristis striata and vermilion snapper Rhomboplites aurorubens before release were evaluated; survival of fishes deflated with one of two tools was compared to survival of nondeflated controls. Capture depths were 20–22 m, 29–35 m, and 43–55 m. Fishes were deflated with a 16-gauge hypodermic needle (99 black sea bass, 64 vermilion snapper) or with a Sea Grant tool consisting of a sharpened stainless steel canula (119 black sea bass, 64 vermilion snapper). Deflated fish were held in cages and observed in situ for 24 h. Controls (108 black sea bass, 89 vermilion snapper) were first segregated in a live well and then held in situ for 24 h in cages. Deflation, especially with the hypodermic needle, provided very significant reductions in mortality of black sea...

Cross-frontal transport associated with upwelling conditions was responsible for modifying ichthyoplankton distributions across the inner continental shelf waters o⁄ the Chesapeake Bay during late August 1988. Two ichthyoplankton assemblages characteristic of the Chesapeake Bay plume and inner-continental shelf waters were defined using multivariate analysis. Members of the plume assemblage (Anchoa spp., Menticirrhus spp., and Micropogonias undulatus) were not retained within the Chesapeake Bay plume, but were instead advected 60 km onto the shelf within a low-salinity water mass. A second assemblage, dominated by several shelfspawned taxa including Etropus microstomus, Prionotus spp. and Centropristis striata was distributed across the shelf. Atlantic croaker, M. undulatus, previously thought to be shelfspawned exhibited a length-frequency distribution that increased from inshore to o⁄shore, and paralleled that of Anchoa spp. This cross-shelf distribution, and the abundance of small ((3.5 mm), pre-flexion larvae inshore suggests that M. undulatus spawned near the plume front and were subsequently transported o⁄shore with the plume assemblage. A mechanism for rapid cross-frontal transport is described. These findings suggest that the transport and recruitment patterns previously described for this taxon in Chesapeake Bay need to be re-examined. Larval survival and recruitment success of shelf-spawned estuarine species, like M. undulatus, are likely tied to oceanographic conditions on the inner shelf related to upwelling and downwelling conditions and plume dynamics, rather than to simple, wind-driven recruitment mechanisms. ( 1999 Elsevier Science Ltd. All rights reserved.

Tag–recapture experiments of black sea bass Centropristis striata (Linnaeus) were conducted in the Great Bay estuary in southern New Jersey U.S.A. to examine habitat fidelity, movements, and growth for recently settled individuals in the first summer ( n =337, 34–106 mm TL ) and the following spring ( n =367, 43–111 mm TL ) in order to determine the temporal and spatial patterns of habitat use. During the 15-month (March 1992–July 1993) study, there were 225 recaptures of 180 fish up to 121 d after their initial release. Recapture frequency was high (31%) for fish released in spring and summer and recently settled fish (21%) released in summer and indicated a high degree of habitat fidelity for both of those age groups during those seasons. Almost all recaptures (99%) were made within 30 m of the release site, and of the 35 fish that were recaptured at least twice, 46% were recaptured at the original capture site. Growth, based on recaptured fish, was fastest during the summer (0.74 mm d −1 ), but averaged 0.45 mm d −1 from spring through fall. The low rate of recapture, as well as shorter recapture intervals, during the fall are consistent with a movement into the ocean at that time. Estimates of total loss (=mortality+emigration) of young-of-the-year released in summer were higher during the first 18 days (0.187 d −1 ) following their release than during subsequent days (0.013 d −1 up to day 88), and averaged 0.033 d −1 for the summer and early fall. In summary, some proportion of the juvenile black sea bass population is resident in polyhaline, subtidal estuarine habitats in the summer and in the spring when they are growing the fastest. As a result, habitat-specific responses during these periods may have important implications for survival and subsequent recruitment to the adult population for this species.

Un protocole a ete developpe pour l'incubation des follicules ovariens de Centropristis striata provenant de femelles dont la ponte a eu lieu en conditions de laboratoire. Les follicules isoles ont subi la maturation apres 15-24 h d'incubation a 25°C et dans un milieu Leibovitz L-15 a 75% contenant relativement de faibles doses d'hormone chorionique humaine gonadotrope (hCG) et d'extrait pituitaire homologue (50% de reponse avec approximativement 2 IU/ml et 0,02 d'equivalent pituitaire par ml respectivement. Durant la maturation in vitro, les follicules ont subi une augmentation remarquable de volume (environ 340%), ceci est lie a la proteolyse des plus grosses proteines du vitellus de l'ovocyte. La maturation des follicules depend de leur taille entre 400 a 600 μm de diametre, avec une reaction maximum entre 530 et 600 μm. La reponse a l'hormone hCG n'est pas inhibe a des temperatures d'incubation comprises entre 15 et 28°C mais le delai necessaire aux follicules pour atteindre 50% de maturation est correle negativement avec des hausses de temperatures (r 2 = 0.97; p ≤ 0,01). Cependant les plus gros follicules (530-600 μm) ne subissent pas de maturation avec des doses fortes (1 μg/ml) de steroides connus pour induire la maturation chez les teleosteens (MISs) 17,20b-dihydroxy-4-pregnen-3-(17,20β) et 17,20β,21-trihydroxy-4-pregnen-3-(20βS) meme apres une premiere incubation des follicules avec 10 IU/ml hCG durant 1, 3 ou 6 h. Ces observations montrent que les follicules de C. striata sont tres sensibles a l'augmentation des doses de gonadotropine et la sensibilite a cette hormone est hautement dependante de leur taille dans une gamme de tailles reduites. Ces resultats preliminaires suggerent egalement que 17,20β et 20βS ne sont pas des steroides majeurs (MIS) induisant la maturation pour cette espece.

The effective use of artificial reefs to enhance populations of black sea bass Centropristis striates along the Atlantic coast of North America requires an understanding of the species' habitat requirements, including food. We examined the diets of adult black sea bass collected from two artificial reefs off New Jersey during August–October 1993 to assess the importance of reef epifauna to the predator. One reef was mature and colonized by an epifauna typical for this habitat in the area. The other reef, 20 km away and in a similar environment, was new and uncolonized by this epifauna. There was no significant difference between reefs in black sea bass diets, which were dominated by early benthic instar, juvenile rock crabs Cancer irroralus. Most of the prey, including the rock crabs, were not specifically associated with the reefs or can be equally common off the reefs. These results and those from similar studies indicate that black sea bass use reefs for shelter but may not depend on the reef-...

Experimental data on photoreceptor cells and visual pigments are the basis for model calculations performed to assess photoreceptor quantum catches under disparate irradiance conditions. Three unrelated species of fish--black sea bass (Centropristis striata), sea raven (Hemitripterus americanus), and adult winter flounder (Pseudopleuronectes americanus)--are considered. In each case, receptor type quantum catches are compared for various water types and depths. By associating the habit and habitat of an organism with the physical properties of its photoreceptors, quantum-catch ratios are found as possible criteria in the selection of pigment peaks (lambda max). In addition to integrated ("total") quantum catches by the receptor types, rates of quantum catches are determined as a function of wavelength. The latter functions are replotted as pairwise difference spectra. These, in turn, are used to assess the ability of receptor types to participate in wavelength discrimination.

A 16-year time series of research trawl catches, commercial landings, and effort data were used to evaluate two areas protected from mobile gear fishing off Cape Cod, Massachusetts, and assess effects of the spring otter trawl fishery for longfin squid Loligo pealeii on local abundance of finfish frequently caught as bycatch. Catch rates were compared between a seasonal closure, a permanent closure, and adjacent waters open to mobile gear fishing. Winter flounder Pleuronecles americanus and scup Stenotomus chrysops were more abundant in the two protected areas. Black sea bass Centropristis striata and windowpane Scophthalmus aquosus were more abundant in the seasonal closure but not in the permanent closure. Abundance indices of summer flounder Paralichthys dentatus and longfin squid were not significantly different between the seasonal closure and the exploited area but both species were less abundant in the permanent closure. Little skate Raja erinacea were more abundant in areas open to trawli...

Throughout the nineteenth and first half of the twentieth centuries, fleets of fishing vessels 20 to 35 ft in length sailed daily, weather permitting, from the South Carolina port of Charleston to coastal offshore waters. Sailing out of sight of land with no navigational aids, the fishermen's reputation as skilled navigators, and a source of high‐quality fresh fish during periods when refrigeration was unavailable, won them the respect and admiration of the community. Known as the “mosquito fleet”; and sailing as a unit, their main objective was the blackfish banks located up to 10 to 15 mi offshore. Depending on season and depth, commonly captured inshore species included whiting (Menticirrhus americanus), summer trout (Cynoscion regalis), croaker (Micropogonias undulatus), and bluefish (Pomatomus saltatrix); deeper‐water species included blackfish (Centropristis striata), porgy (Calamus leucosteus), bastard snapper (Pagrus pagrus), and grunt (Haemulon plumieri). Reports of the fleet fishing bla...

The molecular forms of gonadotropin-releasing hormone (GnRH) in brain-pituitary extracts were determined for snook Centropomus undecimalis and black sea bass Centropristis striata. The extracts were analyzed in both isocratic and gradient high performance liquid chromatography (HPLC) programs. Eluted fractions were tested in radioimmunoassays with 4 different antisera made against 3 distinct GnRH peptides. Results show that snook contain 3 forms of GnRH, all of which are present in males and females irrespective of the stage of the reproductive cycle. Larger quantities of these GnRH peptides are present in snook in the nonreproductive phase than in snook in the reproductive phase. One form of snook GnRH is immunologically and chromatographically similar to salmon GnRH, and a second form is similar to chicken GnRH-II. However, the third snook GnRH appears to be distinct from the 7 known forms of the vertebrate hormone. In contrast, sea bass contain only the salmon GnRH-like and chicken GnRH-II-like forms of GnRH and, hence, appear to match the more usual pattern of GnRH peptides in teleosts. We speculate that one of the GnRH genes was duplicated and then altered in a fish ancestral to snook but not sea bass, even though both species of fish are in the recently evolved Perciformes order.

Fish community composition on natural hard bottom reef areas off the cots of Maryland and northern Virginia was investigated by examining the species composition and seasonality of catch of the most frequently caught species from the black sea bass (Centropristis striata) trap fishery. Hard bottom areas were sampled with wooden fish traps from April to early December 1987. Mean catch per trap and total length were determined for the most commonly caught species. Black sea bass comprised over 96% of the catch overall. The other abundant species were: spotted hake (Urophycis regia), tautog (Tautoga onitis), red hake (Urophycis chuss), conger eel (Conger oceanicus), scup (Stenotomus chrysops), and ocean pout (Macrozoarces americanus). The catches of each species fluctuated through time, apparently as a result of seasonal migration patterns. Most species appeared to migrate inshore in the spring and offshore in the autumn. Ocean pout had not previously been reported to occur south of Delaware and was most abundant during the time of the coldest temperatures. The fish community on hard bottom areas in the Middle Atlantic Bight (MAB) had not been adequately described previously owing to the limitation of trawl nets sampling rough bottom. The hard bottom reef fish community differs considerably from that reported from South Atlantic Bight reef areas as well as from smooth bottom areas on the MAB continental shelf. The present study also provides data to compare with future studies on fish communities inhabiting artificial reefs.

We tested the hypothesis that black sea bass Centropristis striata captured and released by anglers experience zero mortality. Black sea bass captured by hook and line in Nantucket Sound, Massachusetts, were tagged and held in wire cages on site for 48 h. Hook location and physical condition were recorded for each fish. Concurrently, black sea bass used as controls were collected from commercial fish pots, tagged, and held under similar conditions. A preliminary experiment established that neither tagging nor densities up to 12 fish per cage caused mortality. During the 48-h posthooking period, 3 of the 64 fish tested died, resulting in an estimated hooking mortality of 4.7%. The three fatalities were among five fish hooked in the esophagus. We concluded that survival is high among small caught-and-released black sea bass (

The hypothesis was tested that black sea bass Centropristis striata north of Cape Hatteras, North Carolina, were morphologically homogeneous and therefore constituted a single stock. Meristic and morphometric data were analyzed with multivariate analysis of variance and principal components analysis. Significant differences were found throughout the geographic region, most notably between samples from Virginia and Massachusetts. The meristic comparisons provided greater separation between geographic areas than did morphometrics. Results of the analysis can be attributed to environmentally induced phenotypic differences, but further research on spatial and temporal segregation will be necessary to determine if these local groups constitute separate genotypic entities.

Serum levels of 17 beta-hydroxy-4-androstene-3,11-dione (11-KT) and testosterone in the protogynous black sea bass, Centropristis striatus fluctuate annually, correlated with the breeding season. Although serum 11-KT levels in both males and females exhibit seasonality, serum estradiol-17 beta concentrations cycle annually only in the females. Throughout the year, serum estradiol levels in males (127 +/- 56 pg/ml, mean +/- SD) were significantly (P less than 0.05) less than levels in breeding (3,930 +/- 1,390 pg/ml), or nonbreeding females (261 +/- 62 pg/ml). In all female sea bass not undergoing sexual succession, histological examination of the ovary revealed only spermatogonia or ongoing spermatogenesis restricted to the posterior male lamellae; a duct system was nonexistent. In female fish undergoing sexual succession, ovarian tissue was always nonvitellogenic and regressing. Breeding females were not observed to undergo gender change. During sexual succession in the postspawning period, male tissue spread into neighboring female lamellae containing oocytes, gradually replacing them and other female tissue. A male duct system developed on the surface. At any time of year, black sea bass undergoing sexual succession had serum estradiol levels (79 +/- 19 pg/ml) which were significantly less (P less than 0.05) than concurrent female serum estradiol levels. A chi-square test demonstrated that serum estradiol levels in these intersex animals were not significantly different from those of males. The possibility is discussed that sexual succession results from inhibition of ovarian tissue response to steroidogenic gonadotropin.

Twenty-two fish aggregation devices were deployed in 14 m of water off South Carolina. Species composition and abundance were determined by diver visual census on eight occasions from May through November, 1985. A total of 21 families and 36 species of fishes was observed at 121 stations. Pelagic fishes dominated the fauna with a 99.3% relative abundance, and Decapterus punctatus accounted for 97.6% of the individuals. Caranx crysos, Diplectrum formosum, Decapterus punctatus, Centropristis striata and Monacanthus hispidus were the most frequent species. Total fish abundance, number of species and abundance of four of the six most common species were significantly affected by season. Hurricane activity may have caused a significant drop in pelagic fish abundance at the FADs in July. No significant correlations among species abundances were found after removal of season and FAD type effects. Spatial zonation and seasonal occurrence patterns suggest some competition among pelagic fishes. Several factors that regulate FAD faunal abundance and composition are hypothesized, including: juvenile fish availability, availability of shelter, availability of adequate food resources, interspecific and intraspecific competition, severe sea conditions, and sporadic intrusions of large predatory fishes. It is hypothesized that the abundances of benthic and pelagic FAD fishes are correlated and that there is a direct or indirect energetic link between shallow water pelagic and benthic fish assemblages near FADs.

To assess the influence of zoogeographic factors and life-history parameters (effective population size, generation length, and dispersal) on the evolutionary genetic structure of marine fishes in the southeastern USA, phylogeographic patterns of mitochondrial DNA (mtDNA) were compared between disjunct Atlantic and Gulf of Mexico populations in three coastal marine fishes whose juveniles require an estuarine or freshwater habitat for development. Black sea bass (Centropristis striata), menhaden (Brevoortia tyrannus andB. patronus) and sturgeon (Acipenser oxyrhynchus) samples were collected between 1986 and 1988. All species showed significant haplotype frequency differences between the Atlantic and Gulf, but the magnitude and distribution of mtDNA variation differed greatly among these taxa: sea bass showed little within-region mtDNA polymorphism and a clear phylogenetic distinction between the Atlantic and Gulf; menhaden showed extensive within-region polymorphism and a paraphyletic relationship between Atlantic and Gulf populations; and sturgeon exhibited very low mtDNA diversity both within regions and overall. Evolutionary effective sizes of the female populations (N f (e)) estimated from the mtDNA data ranged fromN f (e) = 50 (Gulf of Mexico sturgeon) toN f (e) = 800 000 (Atlantic menhaden), and showed a strong rank-order agreement with the current-day census sizes of these species. The relationship betweenN f (e) and the estimated times of divergence (t) among mtDNA lineages (from conventional clock calibrations) predicts the observed phylogenetic distinction between Atlantic and Gulf sea bass, as well as the paraphyletic pattern in menhaden, provided the populations have been separated by the same long-standing zoogeographic barriers thought to have influenced other coastal taxa in the southeastern USA. However, vicariant scenarios alone cannot explain other phylogenetic aspects of the menhaden (and sturgeon) mtDNA data and, for these species, recent gene flow between the Atlantic and Gulf coasts is strongly implicated. These data are relevant to management and conservation issues for these species.

Three trap types were compared for effectiveness in the capture of demersal reef fishes off the Atlantic coast of the southeastern United States. A series of trials indicated that the chevron or “A” design was most effective overall and for species of commercial and recreational interest in terms of both total weight and numbers of individuals, and that the differences in effectiveness were not due to differences in methods of baiting the traps. Superiority of the chevron design, the largest of the traps, was apparent for all species but one ( Centropristis striata ) even after standardizing catch by trap volume.

Partial sequences of 16S and 12S mitochondrial ribosomal DNA were used to examine the phylogenetic relationships of the primarily eastern Pacific genus Paralabrax (Perciformes: Serranidae) and allied taxa. Paralabrax is considered a basal serranine, which is itself considered the basal subfamily in the Serranidae. Multiple serranines reported closely related to Paralabrax from the genera Serranus, Hypoplectrus, Cratinus, and Centropristis were used as outgroups. Species from the remaining two subfamilies, Epinephilinae and Anthiinae, of the Serranidae were also used in the analyses. The tree of the Serranidae was rooted with the families Polyprionidae and Priacanthidae. Paralabrax, the Serranidae, and the Serraninae were monophyletic in this study. Serranus was found to be paraphyletic. Centropristis, formerly considered the sister taxon to Paralabrax, was not closely related in these analyses. Cratinus agassizii, a monotypic genus from the eastern Pacific, was found to be the sister taxon to Paralabrax. There is greater resolution for intergeneric and subfamily relations than interspecific relationships. A single most parsimonious tree for the interspecific relationships of Paralabrax and allied taxa is proposed. This proposed molecular phylogeny is consistent with known biogeographic processes in the eastern Pacific.

We examined the community structure of fish and selected decapod crustaceans and tested for within estuary differences among habitats at depths of 0.6 m to 7.9 m, in Great Bay and Little Egg Harbor in southern New Jersey. Several habitat types were identified a priori (e.g., eelgrass, sea lettuce, and marsh creeks) and sampled by trawl (4.9 m headrope, 19-mm mesh wings, 6.3-mm mesh liner), monthly, from June 1988 through October 1989. Repetitive (n=4) 2-min trawl tows were taken at each habitat type from 13 locations. The fishes and decapod crustaceans collected were typical of other Mid-Atlantic Bight estuaries but varied greatly inseasonal abundance and species. In the years sampled, bay anchovy (Anchoa mitchilli) was the dominant species (50.5% of the total number), followed by spot (Leiostomus xanthurus) (10.7%), Atlantic silverside (Menidia menidia) (9.7%), fourspine stickleback (Apeltes quadracus) (5.9%), blue crab (Callinectes sapidus) (4.6%), and northern pipefish (Syngnathus fuscus) (4.2%). The biota were examined by multi-dimensional scaling (MDS) for habitat associations and “best abiotic predictor” of community structure. Percent silt combined with salinity was the most important abiotic determinant of the faunal distributions among habitats. Temperature was a major factor influencing seasonal occurrence of the biota but had less effect on habitat comparisons. The analysis confirmed the distinct nature of the assemblages associated with the habitats, that is, eelgrass, upper estuary subtidal creeks, channels, and open bay areas. Several species were associated with specific habitats: for example,A. quadracus andS. fuscus with eelgrass, clupeids with subtidal creek stations,L. xanthurus with marsh channels, and black sea bass (Centropristis striata) and spotted hake (Urophycis regia) with sponge-peat habitat. Species richness appeared to be positively related to habitat structural heterogeneity. Thus, the best predictors for these estuarine fish and decapod crustacean assemblages were seasonal temperature, percent silt and salinity combined, and the physical heterogeneity of the habitat.

Black sea bass in the Middle Atlantic Bight spawn in the summer, at depths of 18 to 45 m, primarily from Virginia to Montauk, Long Island. Young of the year become demersal at 13–24 mm total length and enter estuarine nursery grounds. In fall black sea bass migrate south and offshore to the Chesapeake Bight where the entire population spends the winter. Larger and older fish move offshore sooner than do young of the year and winter in deeper water (73–165 m). Black sea bass may tolerate temperatures as low as 6 C but are captured in larger numbers and more frequently in waters 9 C and above. In the spring sea bass migrate inshore and to the north; adults to their coastal spawning areas, juveniles to estuarine nursery areas (including lower Chesapeake Bay). In recent years, the commercial catch per effort of sea bass has dropped and the fishery lands fewer large and medium size fish. Concurrently domestic trawling effort has decreased somewhat whereas effort by the recreational, foreign trawl, and...

The five principal food finfishes that made up more than 50% of the total catch of food finfishes in the Middle Atlantic region, from New York to Virginia, about 25 years ago were: Atlantic croaker (Micropogonias undulatus), weakfish (Cynoscion regalis), scup (Stenotomus chrysops), summer flounder (Paralichthys dentatus), and black sea bass (Centropristis striata). Of these, only black sea bass had not clearly declined in abundance up to that time. Subsequently, the Middle Atlantic region has shown the greatest proportional decline in landings and their total value of any coastal region of the United States, except for the Great Lakes. From 1929 to 1983, 16 different species ranked among the top five by weight. Whereas abundance of many species changed from natural causes, the major species also suffered from overfishing. In their place, new species of lesser value such as silver hake (Merluccius bilinearis) have been harvested more effectively. Even with these additional species the total catch ...

1. 1. Tissue extracts were prepared from black sea bass kidney, liver, brain, red blood cells and muscle; each of the extracts was analyzed for the following glutathione (GSH)-dependent enzyme activities: Se-dependent and Se-independent GSH-peroxidases, GSH reductase, γ-glutamyl cysteine synthetase, GSH-S-transferase and γ-glutamyl transpeptidase. 2. 2. Each of the black sea bass tissues possessed an active complement of GSH-metabolizing enzymes in a relative distribution similar to that reported for other species including mammals. 3. 3. Tissue GSH concentrations were of the same magnitude as those reported for mammalian tissues.

Several experiments were conducted with pinfish, Lagodon rhomboides (L.). and black sea bass, Centropristis striata (L.), to determine the practicality of using the rate of loss of 65Zn to estimate the metabolic rate of fish under natural conditions. No significant correlations were found between this and oxygen consumption, feeding rate, fish size, or temperature. Restricting fish movement had no consistent effect on zinc loss nor did elevated levels of inorganic zinc in the diet. Because of the lack of positive results, we concluded that the rate of loss of 65Zn is not a practical method for estimating field metabolism of fish.

Mortality rates were estimated from catch curves of black sea bass (Centropristis striata) caught with traps off South Carolina and Georgia in June-July 1978, April-May 1979, and September 1979. Depth of collection ranged from 20 to 46 m. The estimated annual instantaneous rate of fishing mortality in depths less than 30 m was approximately 0.53, while that in depths greater than 30 m was 0.30. Size composition of black sea bass caught in summer over heavily fished artificial reefs was much smaller than that of fish from lightly fished sites, although age composition was virtually identical. For lightly fished sites, size composition of black sea bass in summer was similar to that of fish caught in winter. Size composition (by weight) of commercial catches varied considerably by area, but overall was close to an estimated optimum of 29% small, 23% medium, and 48% large black sea bass. Effects of 203-mm, 229-mm, 254-mm (total length) size limits for all fishermen and a combination 203-mm commercia...

The risk (per caput attack rate) of occupying discrete spatial locations within a school of 25 Atlantic silversides, Menidia menidia , under attack by a black seabass, Centropristis striata , was determined. When available, stragglers were attacked more frequently than the school and suffered a significantly higher risk in comparison to school members. Within the school, central silversides suffered the most attacks and sustained a significantly higher percentage of the risk, as compared to peripheral silversides. This finding contradicts theoretical models of the relative benefit of occupying a given location within an animal aggregation and seems to be explicable in terms of predator attack modes and school size.

1. Black sea bass were injected i.p. with Na 2 SeO 3 (Se-75). A GSH-dependent peroxidase was extracted from the liver via differential centrifugation and gel filtration chromatography. 2. Sea bass liver GSH-peroxidase eluted coincidently with Se-75 and was estimated to have a molecular weight of 72,000. 3. The nature of the selenium-protein bond in the peroxidase was investigated by dialysis vs sodium selenite, glutathione (a sulfhydryl reagent) and alkali. It was concluded that the Se-75 was associated with the peroxidase through a non-sulfhydryl linkage likely to be a C—Se bond. 4. This study confirms that Se is found in a GSH-peroxidase fraction isolated from black sea bass and suggests that Se may play an important role in marine fish.

1. The process of digestion (in vivo and in vitro) upon the chemical form of intrinsic cadmium (Cd) in oysters was examined. 2. Analyses of stomach contents of adult black sea bass (Centropristis strial), 6 hr after consuming oysters previously exposed to Cd, indicated that Cd was associated with five protein fractions having approximate molecular weights of > 160,000, 74,000, 38,000, 11,000 and

Black sea bass, Centropristis striata, were fed shrimp containing [14C]benzo[a]pyrene (200 ppb) in the presence and absence of cadmium (10 ppm) for 10 days. Concentrations of cadmium in muscle tissue were significantly higher when both cadmium and benzo[a]pyrene were ingested simultaneously by the fish. Results indicate that selected tissue concentrations of total benzo[a]pyrene compounds (parent and metabolites) were not affected by the presence of cadmium. The bile contained the majority of benzo[a]pyrene found for all treatments. Ingestion of both contaminants had no effect on hepatic benzo[a]pyrene hydroxylase activity. Histological evidence from the feeding study demonstrated the presence of subcellular inclusions in the intestinal columnar cells and the combined effects of both contaminants appeared greater than either alone.

Black sea bass,Centropristis striata, were daily force-fed capsules containing oyster,Crassostrea virginica, tissues previously exposed to109Cd in the presence and absence of14C-naphthalene (NPH). Black sea bass were sacrificed at 24, 72, and 336 hr, and values for radioactivity associated with Cd and total NPH compounds (including NPH cellular metabolites) determined for various tissues and body fluids. Results indicated that concentrations of tissue Cd were significantly higher when both Cd and NPH were ingested simultaneously. Tissue concentrations of total NPH compounds were generally not affected by the presence of Cd.