William H. Daniels

Protein and energy requirements of juvenile red drum (Sciaenops ocellatus)

Abstract Two studies were conducted to evaluate the effects of different dietary levels of protein and energy on growth and body composition of juvenile red drum ( Sciaenops ocellatus ) grown in a low salinity environment. In each experiment, increased dietary energy resulted in decreased growth, protein efficiency ratio, protein retention, and feed utilization. Whole body lipid tended to increase with increasing dietary lipid. Data from experiment 1 indicated that 35% protein and 1.70 × 10 4 kJ/g were adequate for good growth and high quality body composition (i.e., low fat and high protein) in red drum reared at 22–26°C. Red drum in the second study, reared at 26–33°C, grew best when fed to satiation on a 44% protein diet at dietary energy levels of 1.54 × 10 4 and 1.72 × 10 4 kJ/g. In addition, higher levels of dietary carbohydrate and lipid were associated with an increased hepatosomatic index.

Relative prawn production and benthic macroinvertebrate densities in unfed, organically fertilized, and fed pond systems

Abstract Relative prawn production rates in unfed, organically fertilized, and fed pond systems were evaluated. Populations of benthic macroinvertebrates that potentially serve as forage organisms in these systems were also evaluated and compared with ponds without prawns to evaluate forage preferences. Juvenile prawns (x = 0.36 ± 0.02 g) were stocked into nine 0.04 ha ponds at a density of 39 520 ha −1 . Prawns in three ponds were not fed, prawns in three ponds were fed a complete diet, and three ponds received organic fertilization. Three additional ponds (0.02 ha) served as controls (not stocked with prawns and received no nutrient input). Survival averaged 86%, overall, and was not significantly different among treatments. Average weights of prawns fed complete feed or raised in fertilized ponds (36 and 33 g, respectively) were not significantly different ( P > 0.05). Prawns in unfed ponds were significantly ( P ≤ 0.05) smaller (13 g). Average prawn yields in fed, fertilized, and unfed ponds (1261, 1056, 426 kg ha −1 , respectively) were all significantly different ( P ≤ 0.05). In ponds receiving no nutrient input, macroinvertebrate densities were significantly higher ( P ≤ 0.05) in ponds without shrimp (controls) than in those stocked with shrimp. In ponds stocked with shrimp, macroinvertebrate densities in fed and fertilized treatments were significantly greater ( P ≤ 0.05) than in the unfed treatment, but not significantly different ( P > 0.05) from each other. Insect taxa showed a greater negative response to prawn predation than non-insects. Non-insect taxa demonstrated a more positive response to fertilizer and feed than insects. Although prawn production in organically fertilized ponds was surprisingly high (>1000 kg ha −1 ), economic analysis demonstrated higher net returns when prawns were fed a prepared diet, principally due to the production of greater numbers of large, high value prawns.

Effects of complete and supplemental diets and organic pond fertilization on production of Macrobrachium rosenbergii and associated benthic macroinvertebrate populations

Growth and population characteristics of freshwater prawns, Macrobrachium rosenbergii, fed either a complete diet, a supplemental diet (with fish meal replaced and vitamin and mineral supplements deleted), or the supplemental diet with an adjunct organic pond fertilization regime were examined. Effects of these treatments on potential forage organisms (benthic macroinvertebrates) were also evaluated. Juvenile prawns averaging 0.46 ± 0.49 g were stocked into nine 0.02 ha earthen ponds at 39 520 ha−1. Treatments were evaluated in triplicate ponds. There were significant differences (P 0.05) between regression lines for prawns fed the complete diet and those fed the supplemental diet with an organic pond fertilization regime. At harvest, yield, survival, individual weight, and feed conversion averaged 943 kg ha−1, 76%, 31 g, and 3.9, respectively over the three treatments. Deletion of vitamin and mineral supplements and replacement of fish meal in prawn diets was associated with a significant reduction (P < 0.05) in total benthic macroinvertebrate populations, possibly due to increased predatory pressure by prawns. In ponds in which prawns were fed the supplemental diet, organic fertilization resulted in a significant increase (P < 0.05) in total benthic macroinvertebrates and a 15% increase in average prawn weight at harvest. Results indicate that prawns may increase predation when essential nutrients are deleted from prepared diets and that the supply of potential forage organisms may be increased by organic fertilization.

Pond production characteristics of freshwater prawns Macrobrachium rosenbergii as influenced by the stocking of size-graded populations of juveniles

Abstract A nursery-reared population of 50-day-old post-larvae of freshwater shrimp ( Macrobrachium rosenbergii ) averaging 0.16 ± 0.08 g was divided into three groups. Two groups were size-graded by passive passage through either a 0.64 or a 0.48 cm mesh. Prawns passing through the 0.64 cm mesh proportionately graded into two size groups, 30% upper (0.40 ± 0.13 g) and 70% lower (0.15 ± 0.06 g). Size groups resulting from the 0.48 cm mesh grading were 70% upper (0.21 ± 0.09 g) and 30% lower (0.10 ± 0.03 g). Earthen ponds (0.061–0.073 ha) were stocked at a density of 39530/ha in triplicate with individuals from one of each of the graded or ungraded groups. After a 125- to 138-day growing season, average harvest weight ranged from 24.3 g (ungraded) to 35.4 g (30% upper) and differed significantly among treatments. Growth rates were not significantly different. Samples of prawns removed from each pond were classified into 5 morphotypes: blue claw male (BC), orange claw male + no clawed male (OCNC), small male (SM), berried female + open female (BFOF), and virgin female (VF). Mean harvest weights of the BFOF and OCNC categories in the 30% upper treatment were significantly greater than those for all other treatments. Average yield for the 30% upper and 70% upper treatments (1106 and 884 kg·ha −1 , respectively) were significantly greater than that of the ungraded treatment (775 kg·ha −1 ). Differences in average harvest weight and total yield were achieved through changes in morphotype distributions. Calculated gross revenues in graded populations were 6–73% greater than that of the ungraded population.

Influence of water volume, surface area, and water replacement rate on weight gain of juvenile freshwater prawns, Macrobrachium rosenbergii.

Abstract The effects of combinations of water volume, bottom surface area, and water replacement rate on weight gain of juvenile freshwater prawns, Macrobrachium rosenbergii , were evaluated in two experiments. Prawns were fed a semi-purified diet and individually cultured in clear plastic containers, which were circular and slightly tapered. Each container received an independent water supply in a flow-through system. This design was used to evaluate weight gain in the absence of potentially confounding effects of tactile, chemical and visual stimuli. The first experiment was a 2×2×2 factorial design consisting of two levels of each of the three factors, water volume (1375 and 700 ml), bottom surface area (70.9 and 35.4 cm 2 ), and water replacement rate (86 and 44 min). After 60 days, weight gain of juvenile prawns (initially 221.8 to 227.0 mg) was significantly greater (232%) under conditions of both greater water volume and bottom surface area. Higher water replacement did not compensate for lower water volume. There was significantly more weight gain (149%) with greater bottom surface area at the lower rate of water replacement. However, at the higher rate of water replacement, greater bottom surface area did not result in a significant increase in weight gain. The second experiment was designed to determine at what point the reduction in growth identified in the first experiment became operative. It consisted of two treatments in which weight gain at low water volume and bottom surface area (750 ml and 78.5 cm 2 ) was compared to that at high water volume and bottom surface area (1300 ml and 147.4 cm 2 ) at equal rates of water replacement. Mean stocking weight of the prawns was 7.9 mg and the duration of the experiment was 143 days. Reductions in weight gain began to occur when a critical biomass density of approximately 500 mg/l was attained as reflected in significant differences in weight-frequency distributions between treatments at 90 days and thereafter. The response also reflects a previously identified relationship between maximum density and body size for aquatic animals. A culture volume that allows for maximum, density-independent growth of animals for all treatments is needed for experiments in which growth (weight gain) of crustaceans is used as a response variable to compare performance of different diets. Knowledge of the biomass density that causes growth reduction can be practically applied to establish selective harvest or stock manipulation strategies whereby overall production per unit of time or space can be increased. Alternatively, knowledge of this density threshold can be used to reduce growth rates and thereby assist in distributing production through time.

Aquaculture genomics, genetics and breeding in the United States: current status, challenges, and priorities for future research

Advancing the production efficiency and profitability of aquaculture is dependent upon the ability to utilize a diverse array of genetic resources. The ultimate goals of aquaculture genomics, genetics and breeding research are to enhance aquaculture production efficiency, sustainability, product quality, and profitability in support of the commercial sector and for the benefit of consumers. In order to achieve these goals, it is important to understand the genomic structure and organization of aquaculture species, and their genomic and phenomic variations, as well as the genetic basis of traits and their interrelationships. In addition, it is also important to understand the mechanisms of regulation and evolutionary conservation at the levels of genome, transcriptome, proteome, epigenome, and systems biology. With genomic information and information between the genomes and phenomes, technologies for marker/causal mutation-assisted selection, genome selection, and genome editing can be developed for applications in aquaculture. A set of genomic tools and resources must be made available including reference genome sequences and their annotations (including coding and non-coding regulatory elements), genome-wide polymorphic markers, efficient genotyping platforms, high-density and high-resolution linkage maps, and transcriptome resources including non-coding transcripts. Genomic and genetic control of important performance and production traits, such as disease resistance, feed conversion efficiency, growth rate, processing yield, behaviour, reproductive characteristics, and tolerance to environmental stressors like low dissolved oxygen, high or low water temperature and salinity, must be understood. QTL need to be identified, validated across strains, lines and populations, and their mechanisms of control understood. Causal gene(s) need to be identified. Genetic and epigenetic regulation of important aquaculture traits need to be determined, and technologies for marker-assisted selection, causal gene/mutation-assisted selection, genome selection, and genome editing using CRISPR and other technologies must be developed, demonstrated with applicability, and application to aquaculture industries. Major progress has been made in aquaculture genomics for dozens of fish and shellfish species including the development of genetic linkage maps, physical maps, microarrays, single nucleotide polymorphism (SNP) arrays, transcriptome databases and various stages of genome reference sequences. This paper provides a general review of the current status, challenges and future research needs of aquaculture genomics, genetics, and breeding, with a focus on major aquaculture species in the United States: catfish, rainbow trout, Atlantic salmon, tilapia, striped bass, oysters, and shrimp. While the overall research priorities and the practical goals are similar across various aquaculture species, the current status in each species should dictate the next priority areas within the species. This paper is an output of the USDA Workshop for Aquaculture Genomics, Genetics, and Breeding held in late March 2016 in Auburn, Alabama, with participants from all parts of the United States.Advancing the production efficiency and profitability of aquaculture is dependent upon the ability to utilize a diverse array of genetic resources. The ultimate goals of aquaculture genomics, genetics and breeding research are to enhance aquaculture production efficiency, sustainability, product quality, and profitability in support of the commercial sector and for the benefit of consumers. In order to achieve these goals, it is important to understand the genomic structure and organization of aquaculture species, and their genomic and phenomic variations, as well as the genetic basis of traits and their interrelationships. In addition, it is also important to understand the mechanisms of regulation and evolutionary conservation at the levels of genome, transcriptome, proteome, epigenome, and systems biology. With genomic information and information between the genomes and phenomes, technologies for marker/causal mutation-assisted selection, genome selection, and genome editing can be developed for applications in aquaculture. A set of genomic tools and resources must be made available including reference genome sequences and their annotations (including coding and non-coding regulatory elements), genome-wide polymorphic markers, efficient genotyping platforms, high-density and high-resolution linkage maps, and transcriptome resources including non-coding transcripts. Genomic and genetic control of important performance and production traits, such as disease resistance, feed conversion efficiency, growth rate, processing yield, behaviour, reproductive characteristics, and tolerance to environmental stressors like low dissolved oxygen, high or low water temperature and salinity, must be understood. QTL need to be identified, validated across strains, lines and populations, and their mechanisms of control understood. Causal gene(s) need to be identified. Genetic and epigenetic regulation of important aquaculture traits need to be determined, and technologies for marker-assisted selection, causal gene/mutation-assisted selection, genome selection, and genome editing using CRISPR and other technologies must be developed, demonstrated with applicability, and application to aquaculture industries.Major progress has been made in aquaculture genomics for dozens of fish and shellfish species including the development of genetic linkage maps, physical maps, microarrays, single nucleotide polymorphism (SNP) arrays, transcriptome databases and various stages of genome reference sequences. This paper provides a general review of the current status, challenges and future research needs of aquaculture genomics, genetics, and breeding, with a focus on major aquaculture species in the United States: catfish, rainbow trout, Atlantic salmon, tilapia, striped bass, oysters, and shrimp. While the overall research priorities and the practical goals are similar across various aquaculture species, the current status in each species should dictate the next priority areas within the species. This paper is an output of the USDA Workshop for Aquaculture Genomics, Genetics, and Breeding held in late March 2016 in Auburn, Alabama, with participants from all parts of the United States.

Optimum Ratio of Dietary Protein to Energy for Red Crayfish (Procambarus clarkii)

Abstract Six experimental diets were formulated with protein-to-energy (P:E) ratios ranging from 57 to 160 mg protein/kcal. The diets, which were fed to juvenile red crayfish, contained either 20, 30, or 40% crude protein and 2.5 or 3.5 kcal of total energy per gram of diet. As dietary energy increased, growth of crayfish fed the 30% protein diets decreased, but growth of crayfish fed the 40% protein high-energy diets increased. In general, the percentage of body protein (wet weight) decreased as dietary energy increased. Crayfish fed low-energy (low-fat) diets had lower percentages of body fat. Also, body fat tended to decrease as dietary protein increased. Best growth and protein deposition were observed in crayfish fed a diet with a P:E ratio of 120 mg protein/kcal; this diet contained 30% crude protein and 2.5 kcal/g dietary energy.

Production of Gulf Killifish in the Black Belt Region of Alabama Using Saline Groundwater

Abstract The Gulf killifish Fundulus grandis, commonly called the bull minnow, mudminnow, or cacahoe, is a popular live bait along the Gulf of Mexico coast in the United States. Although culture techniques for Gulf killifish have been established for more than 30 years, this species is not commonly produced. Suitable coastal areas are thought to be one of the limitations. Low-salinity groundwater occurs in much of the United States, including portions of the Alabama Black Belt region; however, the relative abundance of minerals in the water varies. Spawning success was compared among Gulf killifish held in saline groundwater (salinity = 4.2–11.1‰) from four inland sites and in 5‰ synthetic seawater. Gulf killifish production (fry to subadult) was compared between two sites of similar salinity but with different mineral profiles (site A had 4.0‰ salinity and received water from a fertilized source pond; site B had 3.2‰ salinity and received water with no fertilizer additions); initial stocking densities in...

A standardized comparison of semi-intensive pond culture of freshwater prawns Macrobrachium rosenbergii at different latitudes: production increases associated with lower water temperatures

Abstract This study was conducted to evaluate the effects of different ambient water temperatures on growth and population structure of freshwater prawns raised under standardized culture conditions. Juvenile prawns averaging 0.26 ± 0.14 g were stocked into seven 0.04 ha ponds at two study sites. Three ponds were located in Kentucky (KSU:latitude 38 °12′) with seasonal water temperatures averaging 24–26 °C. Four ponds were located in Mississippi (MSU:latitude 33 ° 28′) with a seasonal average of approximately 30 °C. Prawn stocking, sampling, and harvest dates were identical at both locations. Juvenile prawns were single source and were harvested from the same nursery tank for stocking at both locations. The diet used at both sites was from a single production run and was stored under refrigerated conditions. Prawns at both sites were fed twice daily according to a computer generated feeding schedule. Beginning approximately 8 weeks prior to harvest, sampled prawns were also individually identified according to sexual morphotype. At harvest (117 days after stocking) all prawns at both sites were counted, morphotyped, and weighed. Prawn weights were higher at the more northerly site at all samples after 42 days post-stocking. When sampled 64 days post-stocking (5 August) no sexually mature male or females were found. Mature morpho-types were first captured in the Day 83 sampling (25 August). In the Day 106 sampling (16 September), there were no significant differences ( P > 0.05) in numbers or weights of the three male morphotypes between sites. However, among females there were significantly fewer ( P P P P > 0.05) between the two sites in prawn survival (83%), average weight (35 g), and feed conversion (2.3). Production was significantly greater ( P ≤ 0.01) at KSU (1261 kg ha −1 ) than MSU (1091 kg ha −1 ) largely reflecting higher average weights of some morphotypes and slightly higher survivals. Differences in proportions and sizes of female morphotypes probably indicate delayed sexual maturation at the more northerly site, prolonging somatic growth which normally ceases when food energies are redirected to reproductive activities.

Simulating the economic viability of crawfish production: A two‐stage modeling approach

Abstract The purpose of this study was to determine if raising eastern white river crawfish (Procambarus acutus acutus) in the Mid‐Atlantic region year‐round is economically feasible. The possibility for economic success, or even survival, was examined with the use of a two‐stage dynamic‐stochastic simulation modeling framework. Six simulation models were specified in ProModel 4.0 to mimic crawfish farms with different components. Information collected from the ProModel experiments were then used in @Risk, a Microsoft Excel add‐in, in order to determine the economic viability of crawfish farms using capital budgeting methods. Results suggest that crawfish farming in the Mid‐Atlantic region can be feasible assuming optimal farm size and production conditions are attained along with adequate consumer demand.