Florida Pompano Trachinotus Carolinus Research Articles

Performance of Larval Florida Pompano Fed Nauplii of the Calanoid Copepod Pseudodiaptomus pelagicus

AbstractThe Florida pompano Trachinotus carolinus is a highly prized marine fish species, the larviculture of which currently includes the feeding of live rotifers and nauplii of brine shrimp Artemia spp. However, no previous studies have evaluated the feeding of copepod nauplii. In this study, the growth and survival of Florida pompano larvae fed nauplii of the calanoid copepod Pseudodiaptomus pelagicus were compared with those of larvae fed the standard reference diet of enriched rotifers Brachionus plicatilis. Experiments were conducted during the first 7–9 d posthatch (DPH), a period preceding the provision of Artemia nauplii. Treatments included feeding only copepod nauplii during the first day, the first three days, and on all days, as well as copepod nauplii mixed with rotifers during the entire experiment. In addition, the dietary effects on larval fatty acid composition were examined. Feeding copepod nauplii at a density of 2.0–3.5 nauplii/mL during the first day or the first three days of feeding had advantages over feeding only rotifers. However, after approximately 3 DPH, increased quantities of nauplii were needed to provide sufficient nutrients for growth. This was demonstrated in larvae fed copepod nauplii for the entire trial, for which survival was significantly higher than for the other treatments but for which growth was significantly reduced. Larvae fed a mixture of rotifers and nauplii for the entire trial had survival similar to that of larvae fed only rotifers (∼40%); however, growth was greater in larvae fed the mixed diet, suggesting that there is a nutritional advantage to including copepods in the diet. Fatty acid analyses revealed that increased levels of docosahexaenoic acid were associated with larvae fed copepods, which probably contributed to the observed higher survival and growth. These results indicate that there are multiple benefits to feeding copepods to Florida pompano larvae.Received June 6, 2010; accepted August 10, 2010

Association of Mycobacteria in Recirculating Aquaculture Systems and Mycobacterial Disease in Fish

Mycobacterium marinum isolates cultivated from tissue containing granulomatous lesions in Florida pompano Trachinotus carolinus and from biofilm samples collected from their tank and water recirculating system had identical (L1 of 11 bands) repetitive-sequence-based polymerase chain reaction (rep-PCR) DNA fingerprints. A second M. marinum clone sharing 4 of 11 rep-PCR bands with the first clone was isolated from some fish tissues but not from system samples. Water samples yielded low numbers of colonies of mycobacteria (0.08-1.3/mL), but high numbers were recovered from biofilms (260-12,000/swab) and filters (63-21,000/ filter). Mycobacterium hemophilum, M. chelonae, M. trivale, M. gastri, and M. gordonae were isolated from system samples alone.

Amino Acid Availability of Soybean Meal for Florida Pompano

AbstractAvailability of amino acids in soybean meal was determined in a feeding trial with Florida pompano Trachinotus carolinus by using a standard digestibility marker method. Fecal samples were manually stripped from anesthetized fish to avoid contact with water and resultant leaching losses. Apparent amino acid availability coefficients (mean ± SD) for dehulled, solvent‐extracted soybean meal ranged from 78.4 ± 2.2% to 96.5 ± 1.0%. Apparent energy digestibility was 67.4 ± 0.8%. Apparent crude protein digestibility was 84.3 ± 0.5%.

Postmortem Length Changes in Six Florida Fish Species Stored on Ice

AbstractRepresentatives of six species of fishes belonging to the families Lutjanidae, Centropomidae, Pomatomidae, Scombridae, Carangidae, and Sciaenidae were stored on ice for 6 h after being euthanatized, in order to assess postmortem length changes. Standard length, fork length (where applicable), total length using the relaxed caudal fin method, and rigor mortis were measured immediately after deaths and at 30 min intervals thereafter. Two species, lane snapper Lutjanus synagris and common snook Centropomus undecimalis, showed an increase in mean total lengths during the first hour after death. Common snook continued to increase in mean total length for the duration of the study, while lane snapper subsequently decreased. Declines in mean standard, fork, and total lengths also were observed in bluefish Pomatomus saltatrix, Spanish mackerel Scomberomorus maculatus, and Florida pompano Trachinotus carolinus. Minimal changes in mean standard and total length were observed for spotted seatrout Cynoscion nebulosus. There was little direct correlation between rigor mortis and length variation for any of the studied species. The observed length changes may have implications for both law enforcement personnel and anglers.

Production Characteristics and Body Composition of Florida Pompano Reared to Market Size at Two Different Densities in Low‐Salinity Recirculating Aquaculture Systems

AbstractThe effect of culture density on production characteristics and body composition of Florida pompano Trachinotus carolinus reared to market size using recirculating aquaculture systems (RASs) maintained at a salinity of 5‰ was evaluated in a 110‐d growth trial (water temperature = 27.0–28.5°C). Juvenile Florida pompano (mean weight ± SE = 259.0 ± 3.0 g) were stocked into two tanks from each of four separate RASs at an initial nominal density of 6.5 (low density) or 13.0 kg/m3 (high density), equivalent to 200 and 400 fish/tank, respectively. After stocking, fish were fed a 4.7‐mm, floating pelleted diet (50% protein, 14% lipid) twice daily at a targeted daily feed rate of 3% body weight per day. At stocking and at 3‐week intervals thereafter, 10% of the fish population of each tank was sampled to determine production characteristics, including mean weight, weight gain, specific growth rate, absolute growth rate (AGR), feed conversion efficiency (FCE), biomass, and survival. At termination, fish in all tanks were harvested to determine production characteristics and samples were obtained to determine whole‐body composition, energy retention, protein efficiency ratio (PER), protein productive value (PPV), hepatosomatic index, gonadosomatic index, and fillet yield. Results indicated that final weight (570.0 g), weight gain (312.7 g), AGR (2.8 g/d), FCE (25.5%), PER (0.54), and PPV (11.5%) of fish reared at high density were significantly lower than those of fish reared at low density. No differences were observed between density treatments with respect to other measured variables. Additional studies must focus on the development of finishing diets for final stages of Florida pompano production to increase FCE and to determine optimal rearing densities. In addition, research to evaluate the potential of rearing pompano in RASs at salinities lower than 5‰, perhaps through environmental or dietary enhancement of critical ions, is warranted.

Effect of Feeding Strategies on Production Characteristics and Body Composition of Florida Pompano Reared in Marine Recirculating Systems

AbstractThe effect of feeding strategies on production characteristics and body composition of Florida pompano Trachinotus carolinus reared using marine recirculating systems was evaluated in three growth trials (water temperature, 27–29°C; salinity, 23–28‰). A commercial diet (53% protein, 13% lipid) was fed in each trial. In trial 1, mean final weight of juveniles fed 5% of body weight per day (bw/d) in two, three, or six feedings for 38 d was significantly greater than that of Florida pompano fed once daily. In trial 2, Florida pompano that were fed twice daily to apparent satiation (AS) were significantly larger after 54 d than fish fed a fixed ration of 5% bw/d, regardless of initial stocking density (1.3 or 2.6 kg/m3). In trial 3, mean final weight of Florida pompano fed to AS four times daily for 133 d was significantly greater than that of fish fed to AS twice daily. Feeding rate and frequency did not affect feed conversion efficiency or body composition and had minimal effects on specific growth rate. Market‐size pompano had dressed carcass yields greater than 70% and fillet yields greater than 45%. Juvenile pompano raised in recirculating systems in this study grew from an initial weight of 17 g to weights in excess of 450 g (market size) in 4–5 months and to weights in excess of 700 g in 8–9 months.

Acute tolerance of juvenile Florida pompano, Trachinotus carolinus L., to ammonia and nitrite at various salinities

The acute tolerance of juvenile Florida pompano Trachinotus carolinus L. (mean weight±SE=8.1±0.5 g) to environmental unionized ammonia-nitrogen (NH3-N) and nitrite-nitrogen (NO2-N) at various salinities was determined via a series of static exposure trials. Median-lethal concentrations (LC50 values) of NH3-N and NO2-N at 24, 48, and 96 h of exposure were calculated at salinities of 6.3, 12.5 and 25.0 g L−1 at 28 °C (pH=8.23–8.36). Tolerance of pompano to acute NH3-N exposure was not affected by salinity, with 24, 48 and 96 h LC50 values ranging from 1.05 to 1.12, 1.00 to 1.08 and 0.95 to 1.01 mg NH3-N L−1 respectively. Regarding NO2-N, tolerance of pompano to this environmental toxicant was compromised at reduced salinities. Median-lethal concentrations of NO2-N to pompano at 24, 48 and 96 h of exposure ranged from 67.4 to 220.1, 56.9 to 140.7 and 16.7 to 34.2 mg NO2-N L−1 respectively. The results of this study indicate that juvenile Florida pompano are relatively sensitive to acute NH3-N and NO2-N exposure, and in the case of the latter, especially at lower salinities.

Swimming Performance of Juvenile Florida Pompano after Sublethal Exposure to Ethylene Glycol and Methanol: Synergistic Effects

AbstractChemical additives for enhancing deepwater (>305‐m) petrochemical production, such as ethylene glycol and methanol, are used to prevent the formation of gas hydrates in deepwater wells and pipelines and pose threats to marine faunas. Juvenile Florida pompano Trachinotus carolinus were used in controlled experiments to test the effects of 3.0% (volume per volume) ethylene glycol, 1.07% methanol, and a combination of the two chemicals on the swimming performance of individuals. We quantified the sublethal effects of contaminants by comparing differences in pre‐ and postexposure critical swimming speeds (Ucrit) among treatment and control groups. In juvenile swimming performance tests, single exposure to ethylene glycol and to the combination of ethylene glycol and methanol significantly reduced mean Ucrit by 13.4% and 41.1%, respectively. No detectable difference in Ucrit was found for control groups or juveniles exposed solely to methanol. The sublethal effects of single exposures to ethylene glycol and methanol were increased synergistically more than threefold when juveniles were exposed to the contaminants in combination. The reduced ability to sustain high and prolonged performance levels could affect an individual's ability to avoid predators and feed effectively.

Toxicity and Sublethal Effects of Methanol on Swimming Performance of Juvenile Florida Pompano

AbstractDeepwater petroleum production requires that a number of additives, such as methanol, be transported offshore in large quantities, posing the risk of spills. Although these additives may not be highly toxic per se, it is important to evaluate and understand the risks to marine organisms, especially fishes that are often strongly associated with oil production facilities. We evaluated the toxicity and sublethal effects of methanol on the swimming performance of juvenile Florida pompano Trachinotus carolinus. A 24‐h static exposure test identified the median lethal concentration as 1.28% (volume per volume) at 30 practical salinity units and 25°C. The mean critical swimming speed (Ucrit) of juveniles (20.50 ± 4.59 g; mean ± SE) was evaluated before and after exposure to a 1.07% concentration and showed that Ucrit was significantly reduced (P < 0.0002) from 90.10 ± 1.35 cm/s to 84.20 ± 1.36 cm/s in postexposure trials. After exposure and a 17‐h recovery period in clean seawater, the mean 6.5% decline in performance of the treatment group contrasted sharply with a mean increase of 4.0% in the control group, indicating that conditioning, training effects, or both were significantly surpassed by the negative sublethal effects of methanol exposure.

Swimming Performance of Juvenile Florida Pompano Exposed to Ethylene Glycol

Abstract Exposure to ethylene glycol, an additive in petroleum production, may not be immediately lethal to fishes but does affect swimming performance. All life history stages of Florida pompano Trachinotus carolinus are at risk of exposure from spills in the coastal and deep waters of the northern Gulf of Mexico. Toxicity tests on juvenile fish and subsequent probit analysis identified the median lethal concentration (LC50) as 5.63% (volume per volume) at 30 practical salinity units and 25°C. Behavioral observations of treatment and control groups during 24-h exposure and 15-h recovery trials showed that 2.1% ethylene glycol was the lowest concentration at which individuals displayed lethargic behavior relative to controls after 24 h. Fish exposed to concentrations of 3.1% or less became lethargic or distressed relative to controls but showed signs of recovery after 15 h in clean seawater. The mean (±SE) critical swimming speed (U crit) of juveniles (23.1 ± 4.73 g) was evaluated before and after exposur...