bluuebunny/crossref_metadata_2025 huggingface dataset:
Utilization of Animal‐Protein and Plant‐Protein Supplements by Red Swamp Crayfish Procambarus clarkii Fed Formulated Diets1
Authors: Reigh Robert C. , Ellis Simon C.
Published: April 2007

A study was conducted to evaluate alternative protein supplements that could be used to reduce the cost of formulated crayfish diets. Red swamp crayfish Procambarus clarkii were held in the laboratory for 9 wk and fed 30% crude protein diets containing isonitrogenous mixtures of plant and animal protein in a 65:35 ratio. Combinations tested were: soybean meal/menhaden fish meal (SOY/FSH); cottonseed meal/menhaden fish meal (COT/FSH); soybean meal/meat and bone meal (SOY/MB); cottonseed mealheat and bone meal (COT/MB); soybean meal/meat and bone meal/ blood meal (SOYIMB‐B); and cottonseed meal/meat and bone meal/blood meal (COTIMB‐B). Comparison of crayfish weight gain, feed efficiency ratio, apparent net protein and energy retention, and body composition indicated that SOY/FSH was the best protein combination tested. Weight gain was reduced when cottonseed meal replaced soybean meal in diets that contained either fish meal or meat and bone meal. Feed consumption of crayfish fed SOY/MB‐B and COT/MB‐B was lower than that of crayfish fed other diets containing the same plant‐protein supplement and weight gain was lower in crayfish fed blood meal in all but one case. Differences in amino acid composition and amino acid availability of protein supplements, inhibitory effects of gossypol in cottonseed meal, and reduced consumption of diets containing blood meal could have contributed to diet effects. Results suggest that soybean meal is a better dietary protein source for crayfish than cottonseed meal, menhaden fish meal is better than meat and bone meal, and both fish meal and meat and bone meal are superior to a 60:40 meat and bone meal/blood meal mixture. However, cottonseed meal, meat and bone meal, and meat and bone meal/blood meal mixtures could be useful as lower‐cost alternatives to soybean meal and fish meal in diets for pond‐raised crayfish, since the apparent lower protein (amino acid) quality of these ingredients would be unlikely to depress growth of crayfish that have access to natural food in ponds.
Effects of Density Reduction and Supplemental Feeding on Stunted Crayfish Procambarus clarkii Populations in Earthen Ponds1
Authors: Jarboe Herman H. , Romaire Robert P.
Published: April 2007

Density reduction, supplemental feeding, and a combination of two treatments were evaluated as means to alleviate stunting of red swamp crayfish Procambarus clarkii in earthen ponds. Mean total yield of crayfish in low density control ponds averaged 1,218 kg/ha and was 1.5 to 2 times higher (P≤ 0.05) than either the high density control or treatment ponds. Mean individual harvest weight of crayfish averaged 15.1 g and did not differ among treatments. Mean total yield of crayfish in ponds receiving supplemental feed was 32% higher than non‐fed ponds (P≤ 0.05). Mean total yield and size of crayfish at harvest from reduced and non‐reduced treatments did not differ. Density reduction and supplemental feeding implemented in early April did not increase individual crayfish weight to the commercially desirable size of 20 g.
Economic Feasibility of Small‐Scale Sponge Farming in Pohnpei, Federated States of Micronesia1
Authors: Adams Chuck , Stevely John M. , Sweat Don
Published: April 2007

Interest exists in the commercial culture of sponges in the Pohnpei region of the Federated States of Micronesia. Sponge culture is appealing in that capital and labor investment is minimal. Investment requirements for a 0.4‐ha sponge farm totals $650. Average annual production costs total $500. The sponge farm yields 2,400 sponges per 0.4 ha annually. Annual net returns are approximately $1,744 per 0.134 ha component, beginning in Year 4. Profitability is most sensitive to changes in opportunity wage rate, survival rate, and market price. Commercial sponge farming in Pohnpei shows promise as a source of supplemental income.
Evaluation of Soil pH‐Percent Base Saturation Relationships for Use in Estimating the Lime Requirements of Earthen Aquaculture Ponds
Authors: Bowman James R. , Lannan James E.
Published: April 2007

The pH‐percent base saturation relationships of selected subsurface soil horizons were evaluated by fitting theoretical and empirical models to published soils data. The selected models were validated by fitting them to an independent set of data. The selected models did not fit the second set of data as well as the original data, but they provide initial approximations for use in cases when real values can't be measured. Possible reasons for the poorer fit to the second data set are discussed. One possibility for increasing the range of soils to which suitable pH‐percent base saturation models can be fit is to refine the soil classification system being used. Valid pH‐percent base saturation models can be combined with on‐site soil pH measurements and typical cation exchange capacity values to estimate aquaculture pond lime requirements on a broad range of soil types in the field i.e., without reliance on laboratory analyses.
Susceptibility of Three Penaeus Species to a Vibrio campbellii‐like Bacterium
Authors: Hameed A. S. Sahul
Published: April 2007

The susceptibility of larvae and post‐larvae of Penaeus indicus, P. monodon, and P. semisulcatlls to a Vibrio campbellii‐like bacterium was studied by immersion challenge. Exposure to bacteria caused up to 100% mortality, depending upon bacterial dose and time of exposure. Mortality rate was higher for nauplius and protozoeal stages than for mysis and post‐larval stages. Based upon LC50 values at different time intervals, P. monodon was found to be the most sensitive of the three shrimp species to this pathogen.
Physical and Chemical Characteristics of Bottom Soil Profiles in Ponds at Auburn, Alabama, USA and a Proposed System for Describing Pond Soil Horizons
Authors: Munsiri Prasert , Boyd Claude E. , Hajek Ben F.
Published: April 2007

Soil cores were taken from each of three, 2‐, 23‐, and 52‐yr‐old research ponds (650–1,010 m2area) at Auburn, Alabama. Many physical and chemical variables changed in intensity with increasing depth in cores. Compared to original compacted pond soil, sediment contained more moisture; had lower bulk density (<1.4 g/cm3); possessed higher percentages of silt and clay; had greater porosity, specific surface area, and cation exchange capacity; and contained greater concentrations of organic matter and nutrients. Sediment organic matter was highly decomposed as evidenced by low proportions (5–15%) of carbon and nitrogen associated with the light fraction (soil retained on a 53‐μm sieve). Sediment depth at 100‐cm water depth increased with pond age (11.7 cm, 28.3 cm, and 48.3 cm in 2‐, 23‐, and 52‐yr‐old ponds, respectively), but sediment composition did not change greatly over time. Successive layers in cores were as follows: 1) water near the soil‐water interface with a high concentration of solids; 2) high moisture content sediment with dry bulk density <0.3 g/cm3; 3) lower moisture content sediment with bulk density between 0.3 and 0.5–0.7 g/cm3; 4) rapid transition of bulk density from 0.5–0.7 g/cm3to 1.4 g/cm3; 5) original compacted soil with bulk density of 1.4–1.7 g/cm3. We propose that these five layers be referred to as F (flocculent layer), S (stirred or mixed sediment), M (mature, bulk, un‐mixed sediment), T (transitional layer), and P (original, undisturbed pond bottom) horizons, respectively. Superficial, oxidized sediment is termed an Sohorizon, and the reduced part of the S horizon is termed an Srhorizon. The upper part of the T horizon is an MT horizon when it is similar to the M horizon, or a FT horizon when it resembles the P horizon. A system for delineating horizons in pond soil profiles will be valuable in future attempts to classify pond soils.
Evaluation of Sperm‐Activating Solutions in Atlantic Salmon Salmo salar Fertilization Tests
Authors: Krise William F. , Hendrix Michael A. , Bonney Wayne A. , Baker‐Gordon Susan E.
Published: April 2007

The use of saline solutions was tested to determine their efficacy as replacements for ovarian fluid as sperm activators and to eliminate variability encountered with the use of Ovarian fluid. We tested fertilization rate of semen from eight males on Atlantic salmon Salmo salar eggs after five sperm‐activating solutions and a non‐activating saline were substituted for ovarian fluid. We used solutions shown acceptable for use with other salmonid species. The six solutions tested were a non sperm‐activating phosphate‐buffered saline (PBS, 7.2 g/L NaCl, 1.48 g/L Na2HPO4, 0.43 g/L K H2PO4), a Tris buffer (6.99 g/L NaCl, 3.63 g/L Tris and 2.42 g/L glycine), a Borax buffer (12.2 g boric acid/L in solution 1, 76 g disodium tetraborate/L combined 100:118, then 1 L combined with 3.7 L water and 18 g NaCl), and three solutions of 9.25 g/L (125 mM) NaCl buffered to pH 6.0, 7.5, and 8.9. The latter five solutions activated sperm immediately on contact, while PBS required additional water to activate sperm. The PBS solution was the least effective (mean percent eyed eggs 37.6%) for egg fertilization. The mean percent eyed eggs for the other five saline solutions (range 78% to 86%) were not significantly different. Sperm from one male provided significantly lower egg fertilization (39.6%) when compared with the other seven males (67.2–87.4% egg fertilization). Percent egg fertilization was not related to number of live sperm cells per egg. Our results show that osmotically‐balanced sperm‐activation solutions, even those with a pH range from 6.0 to 8.9 provide adequate media for fertilization of Atlantic salmon eggs. Fertilization in a deactivation saline and water reactivation of sperm resulted in low egg fertilization.
Optimum Density of Red Tilapia Oreochromis mossambicus×O. urolepis hornorum in a Pulsed‐Flow Culture System
Authors: D'Silva Aecio Moura , Maughan O. Eugene
Published: April 2007

Abstract.— Densities of 9 tilapia (hybrid Oreochromis mossambicus × O. urolepis hornorum)/m3 gave the highest production among five densities (1, 3, 6, 9, and 12 fish/m3) tested in a pulsed‐flow culture system. Culture of fish in irrigation ditches may have great potential for integrating fish farming with irrigated agriculture. Each 1,000 meters of ditch could potentially produce up to 1,400 kg of tilapia during a 112‐d growing season.
Growth Characteristics of a Neurotoxin‐Producing Chloromonad Fibrocapsa japonica (Raphidophyceae)
Authors: Khan Saleha , Arakawa Osamu , Onoue Yoshio
Published: April 2007

The effects of temperature, salinity, irradiance and pH on the growth of Fibrocapsa japonica (Raphidophyceae) were examined to determine how environmental factors affect the distribution of this species. Optimal growth was observed at temperatures of 15–25 C, salinities of 25–35 parts per thousand (ppt), irradiances of 60–140 μmol quanta/m2 per s and pH between 7.5–8.5. Growth did not occur at temperatures below 10 C or above 30 C nor at salinities below 15 ppt. Fibrocapsa japonica grew when subjected to irradiances of 20–180 μmol quanta/m2 per s, and could tolerate a pH range of 6.5–8.5.
Substitution of Cottonseed Meal for Marine Animal Protein in Diets for Penaeus vannamei
Authors: Lim Chhorn
Published: April 2007

Solvent‐extracted cottonseed meal was used in shrimp Penaeus vannamei diets at levels of 0, 13.3, 26.5, 39.8, 53.0 and 66.3%, substituting on an equal nitrogen basis for 0, 20, 40, 60, 80 and 100% of animal protein mix (53% menhaden fish meal, 34% shrimp waste meal and 13% squid meal). The feeds were formulated to contain 32% crude protein and 3,100 kcal metabolizable energy/kg. Each diet was fed to juvenile shrimp to satiation four times daily for 8 wk. Shrimp fed the three lowest dietary levels of cottonseed meal (0, 13.3 and 26.5%) had similar weight gain, feed consumption and survival. The performance of shrimp was adversely affected when diets containing more than 26.5% cottonseed meal, or 1,100 ppm free gossypol, were fed. Shrimp fed the diet with 39.8% cottonseed meal or 1,600 ppm free gossypol had depressed weight gain, reduced feed intake and high mortality. The groups receiving the two highest dietary levels of cottonseed meal lost weight by the end of week 4 and all shrimp in these treatments died within 6 to 8 wk. These adverse effects were probably due to the toxicity of free gossypol. Shrimp appeared to accumulate gossypol in the body as evidenced by light yellow‐green coloration in shrimp fed diets containing cottonseed meal.
Induced Meiotic Gynogenesis of Paddlefish Polyodon spathula
Authors: Mims Steven D. , Shelton William L. , Linhart Otomar , Wang Changzheng
Published: April 2007

Viable, diploid gynogenetic (gynogenotes) paddlefish Polyodon spathula were produced by activating eggs with ultraviolet‐irradiated shovelnose sturgeon Scaphirhynchus platorynchus spermatozoa and heat shocking. Without irradiation treatment, sturgeon spermatozoa appeared to activate the eggs (up to gastrulation), but did not result in any viable hybrids. Experiment 1 determined that heat‐shock treatment of 35 C for a 2‐min duration within the interval of 2–22 min post‐activation resulted in highest yield of gynogenotes (12–19%) from eggs incubated at 18 C. Experiment 2 applied the heat shock treatment at 35 C from 14.0 to 28.0 min in 2‐min intervals after activation at 18 C for a larger scale of gynogenetic production. Both experiments showed that the best yields of gynogenotes were obtained when the heat shock treatment occurred at 16, 18, and 20 min after activation. When these times were expressed in terms of τ0. units (duration of one mitotic cycle of synchronous cell division related to water temperatures), optimal activations were 0.26, 0.29, and 0.32τ0 (τ0@ 18 C = 63.5 min). Experiment 3 tested the utility of τ0. at two different pre‐shock incubation water temperatures of 18 C and 16 C, and determined that there was no significant interaction in percentage of viable gynogenotes between two different incubation temperatures and the mitotic intervals (0.21, 0.26, 0.31, 0.36, 0.41τ0) tested. Best survival of gynogenotes occurred when eggs held at either pre‐shock incubation water temperatures were shocked at 0.26τ0 All gynogenotes examined were histologically confirmed to have ovarian tissue and were determined to have similar oocyte development to that of normal female (control) paddlefish.
Effects of Temperature and Photoperiod on Reproduction of Female Yellow Perch Perca flavescens: Plasma Concentrations of Steroid Hormones, Spontaneous and Induced Ovulation, and Quality of Eggs
Authors: Ciereszko R. E. , Dabrowskl Konrad , Ciereszko A. , Ebeling J. , Ottobre J. S.
Published: April 2007

The involvement of photoperiod and temperature in the regulation of reproductive processes was investigated in female yellow perch. Initially, all fish kept indoors were exposed to the same water temperature (22°C) and photoperiod (15L:9D). By the end of August, following the first sampling, fish were submitted to different photothermal regimes. Group A3 was maintained under photothermal conditions characteristic for southern Ohio. Group B3 was submitted to a condensed light/temperature regime designed to accelerate photothermal changes. The mean gonadosomatic index in group A3 gradually increased throughout the experiment. Gonadosomatic index in group A3 was higher than that in group B3 from February through April. The highest plasma concentrations of estradiol in group A3 occurred in November and December and exceeded those in group B3. Plasma concentrations of testosterone in group A3 were highest in December and tended to be higher in October and April than in other months. There was no difference in plasma testosterone between groups A3 and B3 except in March when concentrations of this androgen were extremely high in group B3. Ovulation occurred earlier in B regime fish in comparison to that of A regime fish. However, egg quality of fish from regime B was lower than that of fish from regime A. We conclude that the condensed photothermal cycle is not an entirely effective method of inducing out‐of‐season spawning in female yellow perch. These data suggest that although the compression of the photothermal cycle slightly accelerated spawning, it also caused disturbances in patterns and levels of plasma steroids, diminished ovarian and hepatic growth, and reduced the quality of eggs. Thus, temperature and/or photoperiod may have only a modifying effect on the onset of perch spawning, but these environmental cues seem to markedly influence earlier stages of gonadal growth and development.
Dietary Supplementation of Terramycin and Romet‐30 Does Not Enhance Growth of Channel Catfish But Does Influence Tissue Residues
Authors: Rawles S. D. , Kocabas A. , Gatlin Delbert M. , Du W. X. , Wei C. I.
Published: April 2007

Two controlled feeding trials were conducted in which Terramycin and/or Romet‐30 were incorporated into either semipurified or practical diets to provide 25, 50 and 100% of the recommended dosages when fed to juvenile channel catfish at 3% of body weight per day. Data for 4‐wk and 8‐wk weight gain, feed efficiency, and survival of channel catfish fed the various diets were analyzed to determine if these responses could be enhanced by dietary inclusion of either or both antibiotics. In addition, 4‐wk and 8‐wk muscle samples from fish of each dietary treatment were analyzed by high performance liquid chromatography for oxytetracycline (OTC), ormetoprim (OMP) and sulfadimethoxine (SDM) residues. The performance of juvenile channel catfish was not enhanced by the inclusion of Romet‐30 or Terramycin in semipurified or practical diets. Moreover, fish performance tended to decrease relative to that of fish fed the control diet when antibiotics were supplemented in the diet. Residues of OTC, OMP and SDM in the fillets of catfish fed medicated diets generally increased in a time‐ and dose‐dependent fashion. Residue concentrations above the legal tolerance limit of 0.1 mg/kg were noted in most samples from fish fed diets medicated at 100% of recommended levels and in many of the samples from fish subjected to lesser dosages, particularly in those that had been fed diets with Romet‐30. Allowing catfish that were previously fed medicated diets a 3‐wk or 4‐wk withdrawal period effectively decreased the OTC, OMP and SDM contents of fillets to undetectable levels.
Comparison of Tilapia Monoculture and Carp Polyculture in Fertilized Earthen Ponds
Authors: Hassan Shafiqul , Edwards Peter , Little David C.
Published: April 2007

A comparison of a monoculture of Nile tilapia Oreochromis niloticus and a polyculture of carps (silver carp Hypophthalmichthys molitrix; rohu Labeo rohita; and mrigal Cirrhinus mrigala; ratio 4:3:3) was carried out in 200‐m2 earthen ponds fertilized with cattle manure and supplemented with inorganic fertilizer at 3‐kg nitrogen and 1.5‐kg phosphorus/ha per day. A control treatment of a tilapia monoculture without fertilizer inputs was included to assess the effect of pond basal fertility. Net yields of 23.5 kg/pond per 112 d (3.8 t/ha per 1 yr) in the tilapia monoculture and 19.2 kg/pond per 112 d (3.1 t/ha per yr) in the carp polyculture were not significantly different; net yields from unfertilized tilapia monoculture ponds were negative. In the carp polyculture, silver carp was the dominant species at harvest contributing 73% of the total net fish production compared to 9% and 19% by rohu and mrigal, respectively. Water quality data suggested that tilapia yields could have been further improved by increasing fertilization rate but that critical dissolved oxygen concentration constrained this option for carp polyculture.
Effects of Environmental Sodium Chloride on Percent Hatch, Yolk Utilization, and Survival of Channel Catfish Fry
Authors: Weirich C. R. , Tiersch T. R.
Published: April 2007

Abstract.— Only limited research has addressed the effect of salinity on hatching of channel catfish Ictalurus punctatus eggs, and no studies have evaluated the effect of salinity on fry development and survival. This study was undertaken to determine the effect of environmental sodium chloride (0, 1, 2, and 4 g/L. NaCl) on percent hatch, yolk utilization, and survival of channel catfish fry. Experiments were conducted in recirculating systems using seven egg masses (1–2 d old). Each egg mass was divided into smaller portions which remained undissociated or were dissociated with sodium sulfite (NaSO3). Eggs were incubated until hatching. Wet and dry weights were obtained for sacfry at 1 and 5 d post‐hatch to determine wet weight gain and dry weight loss, and fry were sampled 7 d after initiation of exogenous feeding to determine survival. Percent hatch, yolk utilization, and survival of fry hatched from undissociated eggs were greatest at 1 g/L NaCl. In addition, treatment of eggs with NaSO3 significantly reduced percent hatch at all NaCl levels. Although our results indicate that addition of NaCI to hatchery water supplies can increase production of channel catfish fry, additional research is needed before this practice can be recommended on a commercial basis.
A Comparison of Immersion, Immersion/Oral Combination and Injection Methods for the Vaccination of Channel Catfish Ictalurus punctatus Against Edwardsiella ictaluri
Authors: Thune Ronald L. , Collins Lisa A. , Penta Michael P.
Published: April 2007

Abstract.— Four different vaccination regimes, including non‐vaccinated controls (C), immersion/oral combination (IO). late immersion (LI), and injection (IJ), were evaluated for antibody production and protection from challenge in channel catfish Ictalurus punctatus that were hatched and raised in recirculating culture systems over a 28‐wk period. For IO, fry were vaccinated by immersion on day 12 post‐hatch and given an oral booster during week 10 post‐hatch. The LI and IJ delivered vaccine was also administered at week 10 post‐hatch. No titers were detected in the IO group prior to the oral booster at week 10. Mean titers rose sharply after the week 10 vaccinations in all treatment groups, maintained a high level for about 8 wk, and slowly declined over the next 4 wk. Injected fish had significantly higher titers during the primary response period than either LI or IO fish. There was no statistical difference in titers between LI and IO fish during the primary response. After an oral booster delivered during week 22, titers in LI and IO fish increased significantly at week 25, while titers in IJ fish declined despite the booster delivery. An immersion booster delivered during week 25 resulted in significant increases in titers in all vaccinated groups. Of multiple challenges, the only one not marred by concurrent columnaris infections revealed a low, but significant level of protection in IJ fish at 12 wk post‐vaccination.
Freshwater Crayfish Growth Under Culture Conditions: Proposition for a Standard Reporting Approach
Authors: Evans Louis H. , Jussila Japo
Published: April 2007

A review of approaches currently used to measure growth in freshwater crayfish under experimental and pond grow‐out conditions is presented. The review examined 206 papers on growth and production of freshwater crayfish of which 34 were selected for detailed investigation. Selection was based on the amount of information provided in the published report and on the species studied. The review was restricted to six crayfish species: Cherax tenuimanus (marron), C. destructor (yabbie), C. quadricarinatus (red claw), Procambarus clarkii (red swamp crayfish), Astacus astacus (noble crayfish), and Pacifastacus leniusculus (signal crayfish). Growth indices reported included instantaneous growth rate (IGR), absolute growth rate (AGR), slope of log weight against time (GRE) and specific growth rate (SGR, IGR100). Studies were performed for varying time intervals under a wide range of stocking densities. Most reports did not express growth rate as an index but simply reported growth in terms of initial and final weights. The range of approaches used to express growth performance in freshwater crayfish growth studies hinders comparisons of growth rate and production findings. It is suggested that the reports of studies of growth performance in cultured crayfish include a growth rate parameter as well as initial and final weights. SGR is recommended as the parameter of choice since it is based on an exponential growth trend which is typically observed in measurements of weight increase with time in cultured juvenile and early adult crayfish.
Effects of Dietary Nutrient Density on Water Quality and Growth of Red Drum Sciaenops ocellatus in Closed Systems
Authors: Jirsa D. O. , Davis D. A. , Arnold C. R.
Published: April 2007

A 10‐wk growth trial was conducted to determine the effects of dietary nutrient density (protein and energy) on the growth of red drum Sciaenops ocellatus and on water quality in closed recirculating systems. Four test diets, with increasing nutrient density, were formulated to contain 32%, 36%, 40%, and 44% protein and 3.4, 3.5, 3.6 and 3.8 kcal/kg energy, respectively. In addition to growth, total ammonia‐nitrogen (TAN), nitrite‐nitrogen, nitratenitrogen, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids, net solids accumulated and total phosphorus were measured periodically throughout the study. Significant differences in weight gain and total biomass corresponded to increasing dietary nutrient density. Feed efficiency ratios and protein conversion efficiencies increased with increasing nutrient density of the diet indicating the production of fewer waste products per unit gain. Accumulated waste (net solids accumulated expressed as g/kg of fish) decreased with increasing dietary nutrient density. Additionally, there was a significant decrease in COD and suspended phosphorus with increasing dietary nutrient density. TAN, nitrate‐N and BOD5 showed no significant trends presumably due to the ability of the biological filter to process these nutrients. Based on the observed results, manipulation of dietary nutrient density can reduce metabolic wastes and at the same time improve fish growth in an aquaculture system.
Effects of Added Substrate on the Production and Population Characteristics of Freshwater PrawnsMacrobrachium rosenbergiiin Ponds
Authors: Tidwell James H. , Coyle Shawn D. , Schulmeister Greg
Published: April 2007

The effects of added substrate on the growth and population characteristics of freshwater prawns raised in ponds were evaluated. Juvenile prawns (0.3 × 0.2 g) were stocked into six 0.04‐ha ponds at a density of 59,280/ha. In three randomly selected ponds artificial substrate was added sufficient to increase available surface area approximately 20%. Three control ponds received no added substrate. Added substrate consisted of PVC frames with horizontal plastic mesh and vertical suspended seines. Prawns were fed a commercial diet (32% protein) twice daily according to a computer‐generated feeding schedule. At harvest average individual weight, daily yield, and total yield were significantly higher (P < 0.05) in ponds with added substrate (37 g, 12.0 kg/ha per day, and 1,268 kg/ha, respectively). There was no significant difference in survival between treatments, averaging 59% overall. In ponds without substrate the number of small males (SM) was significantly higher and the number of orange claw males (OC) was significantly lower than in ponds with added substrate. Average individual weights of blue claw males, orange claw males, reproductive females, and virgin females were significantly higher (P × 0.05) in ponds with added substrate. Prawns raised in ponds containing added substrate had growth rates and population structures characteristic of prawns stocked at lower densities. Optimum relationships between stocking rates and amounts and types of added substrate should be evaluated as possible methods to increase production levels.
Effects of a Bacterial Inoculum in Channel Catfish Ponds
Authors: Queiroz Julio F. , Boyd Claude E.
Published: April 2007

A commercial bacterial Inoculum cultured on site called Biostart was applied to three channel catfish Ictalurus punctatus ponds at Auburn, Alabama, USA, three times per week from May until October 1996. There were few significant differences (P × 0.1) in concentrations of water quality variables between ponds treated with bacteria and control ponds. In addition, bottom soil carbon and nitrogen did not differ between treated and control ponds. However, survival and net production of fish was significantly (P × 0.1) greater in ponds that received the bacterial inoculum than in controls. The mechanism by which the bacterial treatment influenced fish survival cannot be explained from data collected in this study. Further studies of probiotics are needed to define the potential benefits of these treatments to aquacultural production and to determine their mechanisms of action in pond ecosystems.
Comparative Gametogenesis of Spisula solidissima solidissima and Spisula solidissima similis Cultured in Coastal Georgia
Authors: Walker Randal L.
Published: April 2007

Abstract— The reproductive cycle of two subspecies of surfclams, Spisula solidissimu solidissima and Spisulu solidissimu similis, cultured under similar nursery and field conditions were examined. Monthly gonadal examination showed that S. s. similis initiated gametogenesis, achieved mature status, and spawned earlier than S. s. solidissimu. S. s. similis spawned from January to June, while S. s. solidissimu spawned in May. S. s. similis exhibited an equal sex ratio; whereas, S. s. solidissima had significantly more males than females (1.00 M: 0.32 F). Implications for aquaculture development of surfclams are discussed.
Evaluation of Three In Vitro Enzyme Assays for Estimating Protein Digestibility in the Pacific White Shrimp Penaeus vannamei1
Authors: Lazo Juan Pablo , Romaire Robert P. , Reigh Robert C.
Published: April 2007

Abstract— In vitro enzyme assays are rapid, inexpensive techniques for estimating protein digestibility of feed ingredients. Three assays—the Lazo single‐enzyme assay with porcine trypsin; the Hsu multi‐enzyme assay with porcine trypsin, α‐chymotrypsin, and peptidase; and the Satterlee multi‐enzyme assay with porcine trypsin, α‐chymotrypsin, peptidase, and bacterial protease—were used to estimate relative protein digestibility (RPD) of selected feed ingredients used in diets for the Pacific white shrimp Penaeus vannamei. Ingredients tested were casein, gelatin, rice bran, shrimp meal, soybean meal, wheat gluten, and six varieties of fish meal. A highly significant, inverse, linear relationship existed between final pH in each of the enzyme assays and in vivo apparent protein digestibility of the ingredient in P. vannamei feeding trials. Ranking of RPD coefficients obtained in the Lazo single‐enzyme assay followed closely the ranking of published in vivo apparent protein digestibility coefficients for the same ingredients in P. vannamei digestibility trials. Results indicated that a single‐enzyme assay with porcine trypsin identified differences in protein digestibility of feedstuffs in vitro as well as the two multi‐enzyme assays tested. The porcine‐trypsin, single‐enzyme assay appears to be a potentially useful tool for evaluating protein quality and relative protein digestibility of feedstuffs for P. vannamei.
Observations on the Frequency of Claw Loss in the Crayfish Procambarus charkii
Authors: Powell Mickie L. , Hammer Hugh S. , Watts Stephen A.
Published: April 2007

Abstract— The incidence of claw loss in the crayfish Procambarus clarkii was surveyed in two ponds. Pond 1 contained rice forage, and crayfish were trapped and removed three times per week. Pond C48 contained no supplemental forage, and no trapping occurred in the pond. In March claw loss in both ponds was similar with 87–91% of the population having both claws intact. Males and females showed no difference in the incidence of claw loss in either ponds. By May the abundant rice forage present in pond 1 during March had been depleted; however, the physical appearance of pond C48 changed little. In May claw loss was greater in pond 1 than pond C48; both males and females in pond 1 had a higher incidence of claw loss (increasing from 13% to 37%) than those in pond C48 (increasing from 9% to 17%). Claw loss in pond C48 males did not increase significantly; however, female claw loss increased approximately two‐fold. In May hepatopancreas water content was significantly higher for crayfish from pond 1 when compared to pond C48, suggesting lower energy reserves. During times of environmental stress, such as decreased food availability, decreased structure, low oxygen or temperature extremes, regeneration may influence energy allocation to growth and possibly reproduction, especially if energy reserves are low. Thus, information on the incidence of claw loss and energy reserves in crayfish exposed to different pond conditions may be useful in the design of management strategies.
Consumption and Assimilation of Salmon Net Pen Fouling Debris by the Red Sea Cucumber Parastichopus californicus: Implications for Polyculture
Authors: Ahlgren Molly O.
Published: April 2007

Abstract Fouling debris composed of fish feces, excess fish food, algae, and other particulate organic matter can create environmental problems for aquaculture facilities that rear fish in ocean net pens. Accumulations of organic debris can clog the nets and restrict water circulation which in turn can stress fish. Experiments in which red sea cucumbers Parastichopus californicus were allowed to feed inside floating net pens at a salmon rearing facility in Southeast Alaska showed that sea cucumbers consumed fouling debris and cleared a significant amount of surface area on the nets (P < 0.0001). Sea cucumbers assimilated amino acids and other organic matter from fouling debris two to three times more efficiently than from their natural sediment diet. Muscle development of sea cucumbers consuming fouling debris inside the net pens was also significantly greater than that of sea cucumbers feeding in their natural environment (P < 0.0003). This work suggests that polyculture operations in which commercially important detritivores, like the red sea cucumber, are grown in net pens along with salmon could possibly convert the net from self‐fouling to self‐cleaning and could turn fouling debris into a marketable product (sea cucumber biomass).
Effect of Feeding Frequency and Romet‐Medicated Feed on Survival, Antibody Response, and Weight Gain of Fingerling Channel Catfish Ictalurus punctatus after Natural Exposure to Edwardsiella ictaluri
Authors: Wise David J. , Johnson Michael R.
Published: April 2007

Abstract The efficacy of restrictive feeding regimes and Romet®‐medicated feed (formulated at 40.5‐mg Romet‐30 premix/kg feed) fed at 2.0% body weight was evaluated under field trial conditions for the treatment of naturally induced Edwardsiella ictaluri infections in fingerling channel catfish. After detection of an Edwardsiella ictaluri epizootic, fish were fed medicated and non‐medicated feed every day, every other day and every third day for the duration of the experiment. In addition, experimental treatments also included fish that were completely withheld from feed and those provided Romet‐medicated feed for five consecutive days followed by non‐medicated feed fed daily. Feeding frequency and diet significantly affected survival and weight gain. Survival was greatest among fish that were completely withheld from feed or that were fed medicated feed every other or every third day. The use of non‐medicated feed every other or every third day was equally as effective for reducing Edwardsiella ictaluri associated mortalities as feeding Romet‐medicated feed on a daily basis. Feeding fish Romet‐medicated feed for five consecutive days was not an effective treatment. Agglutinating antibody titers against Edwardsiella ictaluri were significantly lower in all groups of fish fed Romet‐medicated feed for the duration of the experiment. These data indicate that feeding frequency is a primary factor affecting the severity of Edwardsiella ictaluri infection and that prolonged consumption of Romet‐medicated feed may suppress antibody production.
Management Strategies for Production of the Atlantic White Shrimp Penaeus setiferus as Bait Shrimp in Outdoor Ponds
Authors: Samocha Tzachi M. , Burkott Brent J. , Lawrence Addison L. , Juan Ya Sheng , Jones Edward R. , McKee David A.
Published: April 2007

Abstract The geographic distribution of the Atlantic white shrimp Penaeus setiferus is in coastal waters from New York to Florida and around the Gulf of Mexico. Beside its value to commercial fisheries, this shrimp is sold as bait for recreational fishing. Previous data suggest that demand for live bait shrimp cannot be satisfied by commercial fleets. A 120‐d trial was designed to study production of bait size P. setiferus at high densities in eight small outdoor ponds in south Texas. A 24–1 fractional factorial design was applied to study the effects of postlarval (PL) density (350 and 700 shrimp/m2), feed type (A and B), and water circulation methods (with and without airlift pumps or center pond dividers) on shrimp growth, survival and yield. No significant differences in survivals or yields were found between treatments (P = 0.2). Feed type (P = 0.011), airlift pumps (P = 0.021), and center dividers (P= 0.026), had significant impacts on shrimp growth rates. Density effect on growth was not statistically significant (P= 0.055). This study demonstrated that 6‐d‐old postlarvae can be stocked at 700 per square meter and reached a bait size (6.2 g) in 94 d with a 73.6% survival and a yield equivalent to 31,300 kg/ha when offered a commercial shrimp feed. A preliminary economic analysis based on this data suggests that operating a bait shrimp farm in Texas with two crops/yr will show profitability within 7 to 12 yr with an internal rate of return of 6.5 and 17.6%, respectively.
Lethal Low Dissolved Oxygen Concentrations for Postlarvae and Early Juvenile Penaeus setiferus at Different Salinities and pH
Authors: Martínez Evenor , Aguilar Miguel , Trejo Limber , Hernández Isaac , Díaz‐Iglesia Eugenio , Soto Luis A. , Sanchez Adolfo , Rosas Carlos
Published: April 2007

Abstract This study was undertaken to determine the effect of salinity and pH on tolerance to low dissolved oxygen concentration in postlarval (PL 12; 18 mg wet weight) and early juvenile (720 mg wet weight) Peneaus setiferus. Lethal levels of dissolved oxygen were determined in animals at four combinations of salinity and pH (36 and 15 ppt salinity and pH 6 and 8). For postlarvae, the 48‐h LC50 for dissolved oxygen was 1.27 mgO2/L at 15 ppt and pH8, and was significantly lower than that obtained in the other combinations of salinity and pH (P < 0.05). For juveniles, the 72‐h LC50 was 1.16 mg1L at 15 ppt and pH 8, and was significantly lower than that obtained in the other combinations of salinity and pH (P < 0.05). A significant interaction between salinity and pH was observed. These results suggest that the intensive culture of P. setiferus may be conducted at moderate salinity, where shrimp appear to be more tolerant of low concentrations of oxygen than at higher salinities.
A Comparison of Natural and Artificial Diets for Juveniles of the Australian Freshwater Crayfish Cherax destructor
Authors: Verhoef Geoffrey D. , Jones Paul L. , Austin Christopher M.
Published: April 2007

Abstract Growth rates of juvenile yabbies Cherax destructor fed a variety of natural and an artificial diet were compared under controlled conditions. Newly independent (stage 3) juveniles were reared individually in 1‐L pomades for 35 d. The best survival and growth were obtained on live zooplankton, frozen zooplankton, shrimp meal pellets and tubifex worms (survival, 100%; mean weights, 608, 444, 380 and 338 mg, respectively). Intermediate growth and survival was exhibited by crayfish fed chironomid larvae, snails and mussels (survival, 80–100%; mean weight, 138–169 mg). Juveniles fed trout muscle, beef heart and yabby tail gave very poor growth and survival (survival, 50–80%; mean weight, 50–55 mg). The use of shrimp meal pellets as a reference diet for juvenile yabbies is discussed.
Acute Effect of Ammonia and Nitrite on Respiration of Penaeus setiferus Postlarvae under Different Oxygen Levels
Authors: Alcaraz Guillermina , Espinoza Verónica , Vanegas Ceclilia , Carrara Xavier Chiappa
Published: April 2007

The white shrimp Penaeus setiferus is a potential species for culture in the Gulf of Mexico. It has been demonstrated that postlarval P. setiferus is a species sensitive to ammonia and nitrite. In this study, the effect of ammonia and nitrite on the oxygen consumption of Penaeus setiferus postlarvae subjected to different dissolved oxygen concentrations was investigated. Un‐ionized ammonia tended to reduce the oxygen consumption of P. setiferus postlarvae. The addition of 0.4 mg/L un‐ionized ammonia‐N modified the response of the postlarvae to lower dissolved oxygen levels. Exposure to 0.7 mg/L un‐ionized ammonia‐N caused severe effects on the respiratory rate and it was lethal at low dissolved oxygen concentrations. Nitrite exposure decreased the respiratory rate of post‐larvae in high dissolved oxygen concentrations, whereas postlarvae exposed to nitrite under hypoxic conditions showed higher oxygen consumption than unexposed animals. The decreases of the oxygen consumption induced by the interactive effect of ammonia or nitrite and low dissolved oxygen concentration indicate a harmful condition. The results indicate that P. setiferus postlarvae is a sensitive organism to the combined effect of un‐ionized ammonia or nitrite and low dissolved oxygen concentrations.
Wading Bird Depredations on Channel Catfish Ictalurus punctatus in Northwest Mississippi
Authors: Glahn James E , Reinhold David S. , Smith Patrick
Published: April 2007

We interviewed farm managers about their perceptions of wading bird problems and conducted preliminary surveys of wading bird populations at 67 randomly selected channel catfish Ictalurus punctatus pond complexes in northwest Mississippi during December 1995. At a subsample of 24 complexes and 10 other complexes previously surveyed in 1990, we surveyed wading bird populations bimonthly throughout the year in 1996 and observed great blue herons Ardea herodias and great egrets Ardea alba feeding at catfish ponds. Seventy‐five percent of farm managers questioned felt that wading birds were causing losses to their fish stocks, and 74% believed the problem was increasing. Consistent with interview results, 88% of the pond complexes surveyed had one or more wading birds present. Despite reported harassment programs by producers, great blue heron densities at 10 complexes previously surveyed in 1990 had increased by more than eightfold in 1996. Great blue heron densities varied with location, season and time of day, but the average 127‐ha farm supported about 78 herons and 56 great egrets. Despite similar populations, the potential impact of these two species was quite different. Live catfish, averaging 10.3 cm in length (circa 10 g) comprised only 8% of the egret diet by weight, and most of the fish were obtained from fingerling ponds during periods when these fingerlings may be weakened by the bacterial disease, enteric septicemia of catfish. In contrast, live catfish, averaging 16 cm in length (circa 34 g), comprised 44% of the great blue heron diet by weight. Herons foraged from both fingerling and food fish ponds, primarily in the early morning and evening. Based on average population densities and foraging rates, herons at the average 127‐ha farm in northwest Mississippi consumed 114,000 (circa 3,900 kg) catfish, annually. However, further studies are recommended to document production losses.
A Preliminary Study on the Effects of Salinity on Growth and Survival of MullowayArgyrosomus japonicusLarvae and Juveniles
Authors: Fielder D. S. , Bardsley W.
Published: April 2007

Abstract.—Tko experiments were conducted to determine the effects of salinity on growth and survival of mullowayArgyrosomus japonicuslarvae and juveniles. First, 6‐d‐old larvae were stocked into different salinities (5, 12.5, 20, 27.5 and 35 ppt) for 14 d. Larvae grew at all salinities, but based on results for growth and survival, the optimum range of salinity for 6‐d‐old to 20‐d‐old larvae is 5–12.5 ppt. During this experiment larvae held in all experimental salinities were infested by a dinoflagellate ectoparasite,Amyloodiniumsp. Degree of infestation was affected by salinity. There were very low infestation rates at 5 ppt (0.2 parasites/larva). Infestation increased with salinity to 20 ppt (33.1 parasites/larva), then declined with salinity to 35 ppt (1.5 parasites/larva). For the second experiment, juveniles (6.1 ± 0.1 g/fish) were stocked into different salinities (0.6, 5, 10, 20 and 35 ppt) for 28 d. Juveniles were removed from freshwater 3 d after transfer as they did not feed, several fish died and many fish had lost equilibrium. However, when transferred directly to 5 ppt. these stressed fish recovered and behaved normally. Trends in final mean weight and food conversion ratio of juvenile mulloway suggest that fish performed best at 5 ppt. Although salinity (5 to 35 ppt) had no significant (P >0.05) effect on growth, survival, or food conversion ratio of juveniles, statistical power of the experiment was low (0.22). Based on these results we recommend that mulloway larvae older than 6 d be cultured at 5 to 12.5 ppt. Optimum growth of juveniles may also be achieved at low salinities.
Production Characteristics of Pond‐Raised Channel Catfish Ictalurus punctutus Fed Diets With and Without Animal Protein for Three Growing Seasons1
Authors: Reigh Robert C.
Published: April 2007

An experiment was conducted to determlne the long‐term effects of an all‐plant‐protein diet on production characteristics (harvest yield, dressing percentage, and body composition) of catfish Ictalurus punctatus taken from top‐harvested, multiple‐stocked ponds over a 2.5‐yr period of continuous production. Fish in eight 0.08‐ha ponds were fed an extruded, 32% protein control diet (CON) containing animal and plant proteins, while fish in eight replicate ponds were fed an isonitrogenous diet containing only plant proteins, primarily from cottonseed meal and soybean meal (APP). Diets were fed once dally to apparent satiation during the growing season. Ponds were top‐harvested twice per year in the spring and fall and partially restocked after each harvest. CON‐fed fish received 13,335 kg of feed during the 2.5‐yr period. APP‐fed fish received 13,506 kg of feed. Total yields were 5,562 kg of CON‐fed fish and 5,840 kg of APP‐fed fish; average annual yields were 3,477 kgha per yr and 3,650 kgha per yr, respectively (P > 0.05). Feed conversion ratios, 2.5 for CON‐fed fish and 2.6 for APP‐fed Ash, did not differ significantly (P > 0.05). Live weights at harvest averaged 529 g (CON) and 481 g (APP), and were not significantly different. Dressing percentages were 59% for fish fed both diets (P > 0.05). APP‐fed fish had less (P < 0.05) visceral fat and less (P < 0.05) muscle lipid than CON‐fed fish. Results indicate that a lysine supplemented, all‐plant‐protein diet containing 40% cottonseed meal and 20% soybean meal is suitable for long‐term production of channel catfish in earthen ponds and such a diet can reduce the fat content of pond‐reared fish.