Effects of Salinity on Reproduction and Survival of the Calanoid Copepod Pseudodiaptomus Pelagicus

Four experiments were conducted on the calanoid copepod, Pseudodiaptomus pelagicus, to determine the effects of salinity on survival, development time, reproductive output, and population growth in order to define the optimal salinity for culture. To determine the appropriate experimental salinity range we exposed nauplii and adults to abrupt salinity changes from 35 g/L to 5, 10, 15, 35, 42, and 48 g/L at 30 °C and determined survival after 24 hours. The second experiment stocked early stage nauplii into 1 L beakers after which they were cultured using standard procedures for 10 days at six salinities (10, 15, 20, 25, 30, 35 g/L); from this survival, sex ratio, time to maturation, and fecundity were measured. The third experiment evaluated the effects of salinity on brood size, brood interval, and nauplii production by stocking individual adult pairs and monitoring nauplii production daily for 10 days. The fourth experiment determined the effects of salinity on population growth and composition of the population produced by stocking 10 adult pairs and culturing them until five days after the first mature adults were observed. Results from the abrupt salinity change experiment showed nauplii survival decreased following abrupt changes in salinity from 35 g/L to \u3c 15 g/L and \u3e 35 g/L. Additionally, adults do not tolerate rapid changes in salinity from 35 g/L to \u3c 15 g/L but are rather tolerant of changes in salinity up to 48 g/L. Survival from early nauplii to adult was not significantly affected by salinity but survival declined at 35 g/L. Time to first maturation and maturation of the entire population was significantly influenced by salinity and took from 6.3 to 9.5 days. In the individual paired adults experiment, salinity significantly affected nauplii production by affecting brood interval and brood size. The percentage of ovigerous females peaked at 20 g/L and declined at salinities above and below this value. When developing production objectives, aquaculturists must consider salinity because of its numerous effects on the culture of P. pelagicus. The optimal salinity range to achieve high survival and the greatest nauplii production is 15–25 g/L

Stress Survival in Larvae of Florida Pompano (Trachinotus carolinus) Fed Enriched Rotifers (Brachionus plicatilis) and Nauplii of the Calanoid Copepod (Pseudodiaptomus pelagicus)

The Florida pompano, Trachinotus carolinus, is a highly prized marine fish whose larviculture includes the feeding of live rotifers and brine shrimp nauplii. In a previous study, growth and survival of pompano larvae fed nauplii of the calanoid copepod, Pseudodiaptomus pelagicus, were compared to those of larvae fed enriched rotifers, Brachionus plicatilis. There were advantages to including the copepod in the larvae diet. The current study examines the stress tolerance of such larvae. Two trials were conducted: for seven (trial 1) and nine (trial 2) days post-hatch. Larvae were fed diets that included enriched rotifers and/or P. pelagicus nauplii and subjected to varying durations of air exposure (‘sieve stress’). Larvae fed copepods exhibited significantly greater stress tolerance than larvae fed only enriched rotifers. In trial 1, stress tolerance increased as the number of days on which copepods were fed increased. It is possible that stress tolerance improved because of a better nutritional profile of the copepod nauplii

Effects of temperature on reproduction and survival of the calanoid copepod Pseudodiaptomus pelagicus

Four experiments were conducted on the calanoid copepod, Pseudodiaptomus pelagicus, to determine the effects of temperature (24, 26, 28, 30, 32, and 34 °C) on survival, development time, reproductive output, and population growth in order to define the optimal temperature for culture. The first experiment stocked early stage nauplii into 1 L beakers and cultured them using standard procedures until five days after the first mature adults were observed; from this survival, sex ratio, time to maturation, and fecundity were measured. The second and third experiments evaluated the effects of temperature on nauplii production by stocking individual pairs and 25 pairs of adults, respectively; in both experiments nauplii production was determined daily for 10 days. The fourth experiment determined the effects of temperature on population growth and composition of the population produced by stocking 10 adult pairs and culturing them for 10 days at six temperatures. Results indicate survival from early nauplii to adult was significantly affected by temperature and those cultured from 24–30 °C had the highest mean survival. Time to first maturation and maturation of the entire population was significantly influenced by temperature and took from 6.8 to 12.8 days. Temperature significantly affected nauplii production in both individual and groups of paired adults. Temperature affected the mean daily nauplii production by decreasing the brood interval but did not affect the mean brood size. The number of nauplii produced by 25 adult pairs was significantly influenced by temperature; the optimal temperature was 27.5 °C at which 1861 nauplii were produced. The distribution of developmental stages in the population was also affected by temperature; at lower temperatures the population consisted of a greater proportion of nauplii while at 32 °C the population was comprised of more advanced staged individuals. When developing production objectives, aquaculturists must consider temperature because it has multiple effects on the culture of P. pelagicus. The optimal temperature range to achieve high survival and the greatest nauplii production is 26–30 °C. To maintain long-term stock cultures the best temperature may be 24 °C to slow maturation and growth while 28–32 °C may be used to maximize nauplii production by decreasing time to maturation and decreasing brood intervals

Culture of Pinfish at Different Stocking Densities and Salinities in Recirculating Aquaculture Systems

There is great demand for marine baitfish in U.S. coastal states. The supply of marine baitfish in the United States is almost completely wild caught, and this fishery is seasonal and inconsistent. Aquaculture may be able to consistently supply marine baitfish for anglers. Two experiments were conducted to evaluate the effects of stocking density and salinity on the growth and survival of pinfish Lagodon rhomboides cultured in recirculating aquaculture systems. For the stocking density experiment, juvenile pinfish were stocked (50, 200, 400, and 600 fish/m3) into 1,600-L circular tanks in three identical recirculating systems with a salinity of 27 g/L and were cultured for 82 d. Mean survival was not statistically different among densities and ranged from 94.3% to 99.18%. Daily growth of pinfish ranged from 0.35 to 0.39 g·fish−1·d−1. Mean percent weight gain ranged from 624% to 690% and followed a density-dependent trend. Final total length followed a density-dependent pattern, with each increasing density exhibiting statistically significant decreases in length. Mean feed conversion ratio (FCR) ranged from 1.70 to 1.89. In the salinity experiment, juvenile pinfish were stocked at a density of 120 fish/m3 into 1,600-L tanks within four identical recirculating systems and were cultured for 65 d. Treatment salinities were 9 or 27 g/L; each salinity level was maintained in two systems. Two size-classes were stocked separately into two tanks within all four systems, resulting in four replicates per treatment. Mean survival was not significantly different among treatments and ranged from 98.2% to 99.9%. Mean percent weight gain ranged from 234% to 284%, with no significant differences between salinities. Mean FCR ranged from 2.5 to 3.1 and did not significantly differ between salinities, although fish in the small size-class converted feed more efficiently than those in the large size-class. Pinfish show great potential as a new aquaculture species and can be successfully cultured in recirculating systems at stocking densities of 600 fish/m3 and at a salinity as low as 9g/L

Evaluation of nutritional and environmental variables during early larval culture of pigfish Orthopristis chrysoptera (Linnaeus)

Pigfish (Orthopristis chrysoptera Linnaeus) are a commonly used baitfish in the southeastern United States. Aquaculture methods for broodfish spawning and juvenile grow-out have been developed but there is still a paucity of information regarding larval culture methods. Five, short duration (10 days) experiments were conducted to determine effective strategies to yield high larval survival and growth during early development. Experiment one examined the rotifer enrichments Ori-Green, DHA Protein Selco, and AlgaMac 3050 as well as a non-enriched control along with corresponding fatty acid levels in the enriched rotifers and pigfish larvae. Experiment two evaluated three, once daily feeding frequencies of either 5, 10 or 20 rotifers mL−1. Experiment three compared feeding 20 rotifers mL−1 once daily to feeding 5 rotifers mL−1 twice daily. Experiment four examined four different larval stocking densities: 50, 75, 100, or 125 larvae L−1. Experiment five examined green water strategies using either live Tahitian strain Isochrysis galbana (Parke) or Nannochloropsis oculata (Hibberd) paste at either 250 000 or 500 000 cells mL−1 as well as a clear water control. Results indicated rotifer enrichment with DHA Protein Selco and green water application using live T-ISO at 500 000 cells mL−1 had the highest survival of pigfish during early stages of larval culture. A once daily rotifer feeding regime of 20 rotifers mL−1 and stocking density of 50 larvae L−1 also improved survival. These results provide producers with methods to improve efficiency for pigfish larval culture and provide researchers with new foundational data, such as potential fatty acid requirements

Performance of Larval Florida Pompano Fed Nauplii of the Calanoid Copepod \u3ci\u3ePseudodiaptomus pelagicus\u3c/i\u3e

The 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