bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphorus Budgets for Channel Catfish Ponds Receiving Diets with Different Phosphorus Concentrations
Authors: Gross Amit , Boyd Claude E. , Lovell Richard T. , Eya Jonathan C.
Published: April 2007

Phosphorus budgets were prepared for channel catfish Ictalurus punctatus ponds at Auburn, Alabama, that received one of five diets ranging from 0.60 to 1.03% phosphorus. Fish production did not differ (P > 0.05) among diets. There were few differences among treatments with respect to soluble reactive phosphorus, total phosphorus, and chlorophyll a concentrations or gross primary productivity. Phosphorus loss in effluents when ponds were drained for harvest did not differ among treatments (P > 0.05). Phosphorus removed from ponds in fish at harvest and the amounts of phosphorus adsorbed by bottom soils increased as dietary phosphorus concentration increased (P < 0.05). Low‐phosphorus diets did not decrease phytoplankton productivity or improve effluent quality. Uptake of phosphorus by bottom soils is a major factor controlling phosphorus concentrations in pond water. Low‐phosphorus diets can be beneficial in catfish pond management by reducing the phosphorus load to bottom soils and conserving their ability to adsorb phosphorus.
Stunting of Coho Salmon Oncorhynchus kisutch Parr Rearedin Wastewater‐Seawater Ponds
Authors: Allen George H.
Published: April 2007

After entering saline water coho salmon Oncorhynchus kisutch parr often cease to grow (stunt) and many stunts eventually die. Stunted coho parr occurred in an experimental wastewater‐seawater smolt production system constructed in 1971 on the northern arm of Humboldt Bay, Arcata, California, USA. In 1991 many stunted parr (1990 brood) were noted during transfer of juveniles from a 0.02‐ha shaded pond used for summer rearing (July‐December) to a 0.15‐ha unshaded pond used in winter‐spring rearing (January‐May). The cohort suffered a 42% mortality during summer rearing in low salinity water (7 ppt) but deaths due to stunting could not be estimated. When the summer parr were transferred for winter rearing to 15 ppt salinity water, a total mortality of 15% was nearly all related to stunting. A small sample of stunted, but otherwise normal‐appearing, parr found in smolt out‐migrant traps was retained for an additional year of rearing (February 1992—January 1993). There was a 29% survival in these stunts, with survivors attaining an average fork length of 16 cm (range 12–21 cm). The survivors exhibited parr, pre‐smolt, and “smolt‐like” external appearances. Five groups of 1990‐brood smolts were released into Humboldt Bay. They had rates of return to their point‐of‐release (South Pond) similar to other brood years released from the Arcata ponds and other northern California hatcheries. This suggested that whatever produced stunting in the 1990 brood acted independently of endocrinological or physiological factors that produce mortalities in smolts after entering saline water.
Evaluation of Trap Density and Type for Harvesting Crawfish Procambarus spp. from Small Ponds
Authors: Huner Jay V.
Published: April 2007

Harvested crawfish were stocked into 0.15‐ha earthen ponds in March and May at rates of 114, 227, and 455 kg/ha to evaluate the effects of trap density, 27 and 54 traps/ha, on their recapture over 14 d following 3 d of acclimation. Two‐funnel, stand‐up pillow traps and three‐funnel pyramid traps were compared. About 39% and 55% of stocked crawfish were recovered in March and May, respectively. There was considerable growth of those crawfish. Overall catch with both trap densities was equivalent in March but the higher trap density caught 1.3 times more crawfish in May. Pyramid traps caught 1.5–1.9 times more crawfish than pillow traps.
Enrichment of Rotifers Brachionus plicatilis with Eicosapentaenoic Acid and Docosahexaenoic Acid Produced by Bacteria
Authors: Lewis Tom , Nichols Peter D. , Hart Piers R. , Nichols David S. , McMeekin Tom A.
Published: April 2007

Abstract— Two bacterial strains, rich in either eicosapentaenoic acid [EPA, 20:5(n‐3)] (Shewanella gel‐idimarina ACAM 456) or docosahexaenoic acid [DHA, 22:6(n‐3)] (Colwellia psychroeryrhrus ACAM 605) were tested for their ability to enrich rotifers Erachionus plicatilis in these polyunsaturated fatty acids. Rotifers were exposed for 24 h to each bacterial strain and to a mixture of the two strains. They were then harvested and their fatty acid compositions were analysed and compared to those of rotifers that had been either starved or fed yeast Saccharomyces cerevisiae or microalgae Tetraselmis suecica in 2‐L glass flasks. Exposure to 1.4 × 109 cells/ml of the EPA‐producing bacterium only resulted in rotifer EPA levels increasing from 0.1% to 1.2% of total dry weight (%dw). Similarly, following exposure to 1.0 × 109 cells/mL of the DHA‐producing bacterium only, rotifer DHA levels increased from below detection to 0.1% dw. When exposed to a mixture of the two bacterial strains, containing 7.0 × 108 celldml of the EPA producer and 5.0 × 108 cells/mL of the DHA producer, the rotifers’final EPA and DHA levels were 0.5% dw and 0.3% dw respectively. Although feeding strategies need refining, these results show, for the first time, that rotifers can be enriched with DHA from bacteria, and that rotifers can be enriched simultaneously with both DHA and EPA from different bacterial strains.
Progress in Controlled Maturation and Spawning of Summer Flounder Paralichthys dentatus Broodstock
Authors: Watanabe Wade O. , Ellis Eileen P. , Ellis Simon C. , Feeley Michael W.
Published: April 2007

Abstract— Wild‐caught, adult summer flounder Paralichthys dentatus (avg. wt. = 740 g; range = 264–1,540 g; N= 60), collected in northeastern US coastal waters during October 1994, were transported to Vero Beach, Florida in March 1995 and held in 2.6‐m3 indoor tanks through November 1995 under two artificial photothermal regimes: (1) natural regime, simulating natural habitat conditions; and (2) accelerated thermal regime, with seasonal temperature changes advanced by one month. A third group of fish was held in outdoor tanks under ambient photothermal conditions. Under all photothermal conditions, onset of vitellogenesis was associated with declining daylength and temperature, beginning in the accelerated group, then progressing to the natural and the ambient groups. From 20 September to 28 November 1995, 23 vitellogenic stage females from the accelerated and natural regimes were implanted with a cholesterol‐cellulose pellet containing LHRH‐a (100 μg/kg body wt). Females with initial mean oocyte diameters ranging from 258–456 μm spawned voluntarily 2.5–5.5 d postimplantation, while no maturational response was obtained from females with mean diameters ranging from 165–231 μm. Two females were spawned twice during the study period by LHRH‐a pellet implantation. Infrequent, natural spawning without hormone intervention was also obtained. Females released from 22.7–396.9 × 103 eggs on the first day of spawning, with fertilization and hatching rates of 0–93.470 and 0–81.1%, respectively.
Accumulation of Chemical Elements in Texas Shrimp Pond Soils
Authors: Ritvo Gad , Dixon Joe B. , Lawrence Addison L. , Samocha Tzachi M. , Neill William H. , Speed Michael E
Published: April 2007

Abstract—This study evaluated changes in chemistry of shrimp pond soils over one production cycle. Several soil nutrients, pH, organic matter, and total soluble salts were analyzed in the upper 10 cm of pond‐bottom soil on two Texas shrimp farms in two consecutive years. Soil concentrations of S, P, Ca, Mg, K, Na, Mn, and Zn increased from one year to the next, S increased by 400 ppm. Organic matter did not accumulate. The pH decreased in all pond soils, owing perhaps to the oxidation of organic matter and/or inorganic compounds. There was no statistical difference in shrimp yield between the two consecutive years. These results indicated that the accumulation of S and soluble salts derived from seawater and feed should be monitored and evaluated to prevent excessive chemical element loading of pond soil and discharge water.
Evaluation of a Methyl Anthranilate‐Based Bird Repellent: Toxicity to Channel Catfish Ictalurus punctatus and Effect on Great Blue Heron Ardea herodias Feeding Behavior
Authors: Dorr Brian , Clark Larry , Glahn James E , Mezine Igor
Published: April 2007

Abstract— We evaluated the methyl anthranilate‐based bird repellent, ReJeX‐iT TP‐40™ (TP‐40), for 1) its toxicity to channel catfish fingerlings (catfish), Ictalurus punctatus; 2) its effect on great blue heron (heron), Ardea herodias feeding behavior; 3) its efficacy in reducing heron predation on catfish; and 4) its effects on catfish growth. TP‐40 effectively maintained MA concentrations near the water's surface and below toxic levels for catfish in the water column. Water samples collected from 0.03 and 0.35 m below the surface of catfish rearing tanks (6,664 L) treated at application rates up to the equivalent of 200 kg/ha contained less than 5 ppm active ingredient, which is less than the no observable effect limit for catfish fry. No treatment‐related mortality of catfish was observed. Handling times of catfish fingerlings captured by herons from tubs treated with TP‐40 initially increased at application rates of 19.6 kgha or greater but decreased as a function of the number of catfish captured. Under simulated aquaculture conditions, TP‐40 did not affect the number of catfish eaten by herons from ponds treated at surface application rates of 0, 2, 22, and 220 kglha. TP‐40 had no affect on the time herons spent handling live or dead catfish. Ponds treated with TP‐40 at 220 kgha had a 46% increase in visibility (secchi disk method) and a 58% reduction in total suspended solids, suggesting the formulation was phytotoxic. TP‐40 did not affect fish growth. Analysis of individual behavior showed that herons may have habituated or become indifferent to the effects of the repellent after repeated exposure. Under the conditions of the study, herons did not maintain their body weight unless catfish were made available by disease or supplemental feeding, suggesting that herons may be inefficient at capturing healthy catfish. Surface applications of TP‐40 at 20 to 220 kg/ha were not effective in limiting predation by herons.
Ineffectiveness of Water Circulation for Golden ShinerNotemigonus crysoleucasProduction in Ponds
Authors: Stone Nathan , Rowan Martha
Published: April 2007

Abstract—Continuous aeration at 0.5–0.9 kWha during summer months increasingly has become a baitfish industry practice, with aerators also serving as water circulators. Our study examined the impact of circulating pond water on golden shinersNotemigonus crysoleucasproduced by typical commercial practices. Ponds (0.04‐ha) were circulated with 0.25‐kW pumps during two consecutive summers. In the first trial juvenile golden shiners were stocked at 282,800/ha and treatment ponds circulated from 0900–1600 h. In the second trial, stocking rate and daily hours of circulation were increased (800,600 fishha and 24 h, respectively). After 56 d (trial 1). gross yields (mean ± SE) were 771 ± 69 and 668 ± 44 kgha for control (uncirculated) and circulated ponds, respectively. Second trial gross yields (63 d) were 1,330 ± 70 and 1,177 ± 61 kgha for the control and circulated treatments, respectively. While circulated ponds showed a reduction in stratification based on temperature and dissolved oxygen profiles, there were no significant differences in golden shiner growth, yield or survival. Under the conditions of our trials, water circulation was an ineffective culture practice.
Delivery of Bioencapsulated Oxytetracycline to the Marine Shrimp Penaeus monodon
Authors: Roque A , Turnbull J. F. , Gomez‐Gil B.
Published: April 2007

Abstract Post larvae of shrimp Penaeus monodon were fed Artemia sp. enriched with oxytetracycline (OTC). The amounts of this antibiotic in the Artemia sp., the shrimp, and the water of the experimental system were measured by radial diffusion bioassay. The results indicated that 11% of the OTC was taken up by the Artemia sp. After 8 d of being fed OTC‐enriched Artemia sp., the shrimp were found to contain 3.12 μg OTC/shrimp, which is twelve times greater than the average minimum inhibitory concentration (MIC) cited in the literature for sensitive strains of Vibrio spp. The recommended therapeutic dose for treatment of bacterial infections is four times the MIC.
Age‐Related Sperm Quality of Captive Striped Bass Morone saxatilis
Authors: And Verapong Vuthiphandchai , Zohar Yonathan
Published: April 2007

Three groups of captive‐reared striped bass Morone saxatilis ages 1, 3 and 12 yr, were examined for age‐related changes of sperm characteristics including short‐term storage. All groups had similar ranges of the following parameters (mean× SEM): expressible milt (5.6× 0.5 mI/kg body weight (BW) to 7.5× 2.1 mL/kg BW), percentage of motile sperm (55× 6% to 60× 2%), duration of sperm motility (69× 3 sec to 72× 5 sec) and percentage of viable sperm (91× 2% to 93× 2%). Compared to the 1 and 12‐yr‐old fish, the 3‐yr‐old fish produced the greatest number of spermatozoa (1,190× 370× 109 spermatozoa/kg), sperm concentration (120× 8 × 109 spermatozoa/mL) and spermatocrit (74× 4%). In addition, during short‐term storage at 4 C, extender‐preserved sperm samples of the 3‐yr‐old group showed a significantly higher (P < 0.05) percentage of motile sperm and duration of sperm motility, compared to the other two groups. This suggests that short‐term storage may be affected by the age of the male fish. Sperm longevity of the 3‐yr‐old group was successfully maintained for as long as 15 d, longer than that of the 1‐yr‐old group (9 d) and 12‐yr‐old group (7 d). Overall, the 3‐yr‐old fish appeared to have superior sperm quality than the 1 or 12‐yr‐old fish based on higher sperm production and increased sperm longevity.
Acute Toxicity of Ammonia and Nitrite to White Shrimp Penaeus setiferus Postlarvae
Authors: Alcaraz Guillermina , Chiappa‐Carrara Xavier , And Verónica Espinoza , Vanegas Ceclilia
Published: April 2007

Penaeus setiferus postlarvae were exposed to acute levels of ammonia, nitrite, and to a mixture of both by a short‐term static method, The 24h, 48‐h and 72‐h LC50 values for un‐ionized ammonia were 1.49, 1.21 and 1.12 mg/L NH3‐N (un‐ionized ammonia as nitrogen), and 11.55, 9.38 and 8.69 mg/L ammonia‐N (un‐ionized plus ionized ammonia as nitrogen). The 24‐h, 48‐h and 72‐h LC50 values for nitrite were 268.06, 248.84 and 167.33 mg/L nitrite‐N (nitrite as nitrogen). Nitrite was much less toxic than ammonia. The joint effect of ammonia and nitrite on the postlarvae was synergistic at 48‐h exposure and antagonistic after 72 h. Postlarvae of P. setiferus may be considered as organisms sensitive to ammonia and nitrite.
Feeding Levels of the Southern Brown Shrimp Penaeus subtilis in Response to Food Dispersal
Authors: Nunes Alberto J. P. , Parsons G. Jay
Published: April 2007

The development of efficient feed management strategies in shrimp farming involves the investigation of aspects related to time of feed distribution, feeding rates, feeding frequency, and feed dispersal methods. This work examined the feeding levels of Penaeus subtilis in response to food dispersal method under semi‐intensive culture conditions. The study consisted of two treatments: 1) a uniform feed dispersal over the culture area, and 2) concentration of feed in 0.2‐m2 circular feeding trays. For each, three 105‐m2 rectangular enclosures were installed in a single shrimp grow‐out pond and stocked with P. subtilis at a density of 14.29 postlarvae/m2. Shrimp were fed daily at 0600, 0930 and 1430 h and sampled 30 min after feed distribution at 12‐d intervals. After collection, shrimp weight was determined, their stomachs dissected and weighed. A total of 2,160 stomachs of P. subtilis were collected during a 89‐d rearing cycle. Relative occurrence of artificial versus natural food in stomach contents was determined by stable carbon isotope mass spectrometry. Density of polychaetes in the substrate was monitored at each sampling period. After harvest, sediment samples were collected for physical and chemical analyses. In general, differences in shrimp growth between feeding methods were not significant. Final shrimp survival rates were between 69.0 ± 6.9% and 71.9 ± 3.7%. Stomach content weight of P. subtilis was significantly higher when feed was broadcast than for feed concentration. Average stomach content weight remained constant throughout the rearing cycle, although progressive increases in feed Occurrence were detected in P. subtilis diet. No periodicity in food intake along sampling periods could be related to increases in shrimp carapace length. Food intake was significantly lower at 0600 h than at 1430 h and at 0930 h, respectively. In both treatments, over half of the food contained in the stomach contents of shrimp was derived from artificial food. Sediment chemical analysis indicated statistically lower levels of sodium in the pond bottom of concentrated treatment. However, no short‐term detrimental effects were detected on sediment chemical quality. Results indicated that feed broadcasting resulted in a greater access and a higher consumption of food among the cultured shrimp population, a lower number of empty stomachs, and a greater occurrence of artificial food in P. subtilis stomach contents.
Growth and Mineral Absorption by Striped Bass Morone saxatilis Fed a Plant Feedstuff Based Diet Supplemented with Phytase
Authors: Papatryphon Elias , Howell Rachel A. , Soares Joseph H.
Published: April 2007

Two experiments were conducted to determine the effects of phytase on growth, apparent phosphorus (P), calcium (Ca), iron (Fe), zinc (Zn), magnesium (Mg), and copper (Cu) absorption, and apparent protein digestibility by striped bass Morone saxatills fed a high phytate diet. In experiment one, four diets with graded levels of phytase supplementation, 0, 500, 1,000, and 2,000 phytase units/kg of diet (PUkg), and a diet supplemented with inorganic P (positive control, total P, 0.73%; phytin P, 0.35%) were assigned to duplicate tanks, and were fed to fingerling striped bass for 16 wk. A digestibility trial was conducted at weeks 16–18, using 0.5% Cr2O3 as an indigestible marker in the diets. Phytase was sprayed post‐extrusion on the basal diet (P‐total, 0.58%; P‐phytin, 0.35%). Experiment two consisted of a 2‐wk digestibility trial with three treatments: 0 (basal; total P, 0.73%; phytin P, 0.34%), 1,000, and 2,000 PU/kg, assigned to four, three and three replicate tanks respectively. Each tank contained an average of 20 striped bass (mean weight: 400 9). The diet used was similar to the basal in experiment one, which was modified to have low essential trace mineral concentrations, in order to increase the sensitivity of the assay. In experiment one, significant improvements (P≤ 0.05) in growth, feed conversion ratios, and vertebral and scale ash concentrations of fish at the end of the experiment were achieved with either added inorganic P or increasing phytase supplementations. Results from both digestibility trials indicated that P absorption was improved with the addition of at least 500 PUkg. Absorptions of Ca and Fe were significantly increased (P≤ 0.05) and Zn absorption marginally improved (P≤ 0.06) when at least 2,000 PU/kg was supplemented to the diet. Protein digestibility, Mg and Cu absorption were not significantly different in any treatment. Whole carcass P retention was significantly improved with the addition of 1,000 PU/kg, and 2,000 PU/kg, when compared to fish fed the basal diet, 500 PU/kg and positive control treatments. Results from these experiments indicate that phytase supplementation of at least 1,000 PU/kg is adequate to maintain growth rate and health comparable to an inorganic P supplemented diet. In addition, bioavailability and utilization of P is increased with increasing phytase supplementation. Diet supplementation of 2,000 PU/kg increased Ca, Fe, and Zn digestibility by striped bass fed a high phytate diet.
A Dynamic, Stochastic Model of a Land‐Based Summer Flounder Paralichthys dentatus Aquaculture Firm
Authors: Zucker David A. , Anderson James L.
Published: April 2007

Exploring the possibilities for commercial aquaculture has historically concentrated on reducing production uncertainty by focusing on an animal's biology and the engineering of the production facility. However, the aquaculturist faces both production and market uncertainty, both of which may significantly affect the economic feasibility of a production facility. We developed a dynamic stochastic model to compare alternative production and marketing scenarios and used the net present value of returns to evaluate the scenarios. Based on the model and the scenarios we examined, firms producing summer flounder Paralichthys dentatus are unlikely to be profitable unless they locate near and use a source of salt‐water, sell their product predominately to sushi chefs (or other premium market outlets) who desire medium‐sized live fish, and engage in strategies that account for market dynamics.
Induction and Recovery from Anesthesia in Channel Catfish Ictalurus punctatus Fingerlings Exposed to Clove Oil
Authors: Waterstrat Paul R.
Published: April 2007

Abstract.— The use of clove oil as an anesthetic for channel catfish Ictalurus punctatus fingerlings was examined. At 100 mg/L. clove oil induced anesthesia within 1 min following exposure. Fish recovered from a 10‐min period of anesthesia in 100 mg/L clove oil within 4 min following removal from the anesthetic solution. At clove oil concentrations of 150 mg/L or greater, recovery times were prolonged, requiring longer than 10 min for recovery. At 300 mg/L, mortality was observed with half of the catfish fingerlings failing to recover from the 10‐min exposure. Fish could be safely maintained in 100 mg/L clove oil for periods of up to 15 min; exposure for longer than 15 min produced both prolonged recovery times and mortality. At a concentration of 100 ma clove oil produced responses similar to those of the commonly used fish anesthetic MS‐222. The low cost of clove oil relative to MS‐222 and the extensive testing and use of clove oil in dentistry and as a food ingredient make clove oil an attractive candidate as a fish anesthetic.
Application of Polymorphic Microsatellite Loci in a Channel Catfish Ictalurus punctatus Breeding Program
Authors: Waldbieser Geoffrey C. , Wolters William R.
Published: April 2007

Abstract.— In order to monitor spawning success in earthen ponds, individual channel catfish Ictalurus punctatus broodfish were identified prior to stocking by genotype analysis with polymorphic microsatellite DNA markers. Individual spawns were collected and reared in a hatchery, and eight sac‐fry per spawn were sampled for genotype analysis. Mendelian inheritance of microsatellite alleles was used to identify parents of each spawn. The probability of detecting a falsely matched offspring and spawning pair was >99%. Average spawning success was 44% (17–80%). Multiple spawning by males was found in seven of the eight ponds sampled. In these ponds, 47% of the males fertilized 2–6 egg masses over 1–8 wk, although most were 2–3 wk apart. Four different spawns were identified as two full‐sib families and were probably due to interrupted spawning. Parent/offspring genotype analysis will be useful for production of half‐sib families for estimation of genetic components of variation, estimation of effective breeding population, and selection of broodstock for multiple reproductive traits under natural spawning conditions.
Disinfection, Microbial Community Establishment and Shrimp Production in a Prototype Biosecure Pond
Authors: Bratvold Delma , Lu Jingrang , Browdy Craig L.
Published: April 2007

Plankton community establishment and shrimp production in a prototype biosecure pond were compared to three control ponds. The biosecure pond was enclosed and intake water was disinfected, while control ponds were neither enclosed nor disinfected. All ponds were managed with no water exchange and stocked with 100 postlarvae/m2, Litopenaeus vannamei. Residual oxidant concentrations in the biosecure pond dropped rapidly after cessation of chlorinated water addition. This was followed by a sharp increase in water column bacterial abundance, after which the pond was fertilized and inoculated with cultured Chaetocerous gracilis. After crash of the initial C. gracilis bloom in the biosecure pond, this species was not observed again. Following initial large fluctuations in biosecure pond bacterial abundance, phytoplankton biomass, oxygen consumption and nitrification rates, these parameters appeared to stabilize at levels similar to the control ponds. Early season compositional differences in phytoplankton, zooplankton, and bacterial communities were observed. No differences were seen in late‐season phytoplankton and bacteria; however, zooplankton biomass tended to be lower in the biosecure pond than in the control ponds throughout the season. Shrimp production in all ponds was greater than 9,000 kg/ha. Production in the single biosecure pond was not a significant outlier compared to production in the triplicate control ponds.
Development of a Model for Describing Accumulation of Color and Subsequent Destruction by Ozone in a Freshwater Recirculating Aquaculture System
Authors: Christensen J. Michael , Rusch Kelly A. , Malone Ronald E
Published: April 2007

The purpose of this study was to develop a mathematical model to assist in the determination of design numbers for color destruction by ozone as a function of feed rate. A mass balance model was developed that takes into account methods of introduction and removal of color, including removal by ozone. Because direct measurement of color mass or concentration is difficult, a representative unit was developed during this study called the color mass equivalent (CME). The CME represents a direct measurement of absorbance at 436 nm, which is a unitless measurement, multiplied by the system volume. The CME is directly proportional to the true concentration of color causing compounds at that wavelength. Once the model was developed, two studies were run to test the model. A 1,500‐L recirculating fish system was set up with a 57‐L bead filter and six 1‐L fluidized sand beds. Approximately 45 kg of channel catfish Ictalurus puncfatus were placed in the system and fed 0.25 kg of 32% protein feed per day (0.55% body wt.). Once the system reached stable conditions, the system was flushed with clean water and samples were taken to estimate the accumulation rate of color in the system. After 5 wk, an ozone unit was activated and samples were taken to determine the destruction rate for color. Once an accumulation rate had been determined, a second study was performed to corroborate this value. The same ozone unit was installed on a 5,000‐L recirculating fish system being fed 0.49 kg per day with a 171‐L bead filter. Samples were taken to determine the destruction rate for color. The accumulation rate for color was 12.6 CME/kg feed and the destruction rates were 1.7 CME/g O3 in the first study and 0.82 CMWg O3 in the second study. This calculates to a range of 7 to 15 g O3/kg feed to remove the color produced by the feed.
Utilization of Deoxynivalenol‐Contaminated Hard Red Winter Wheat for Shrimp Feeds1
Authors: Trigo‐Stockli Dionisia M. , Obaldo Leonard G. , Dominy Warren G. , Behnke Keith C.
Published: April 2007

Wheat is used in shrimp feed as protein and energy sources, as well as a nutritive binder that promotes water stability. However, wheat may be contaminated with deoxynivalenol (DON or vomitoxin) when wet weather conditions prevail during the growing season. Deoxynivalenol‐contaminated wheat was added to shrimp diet to obtain DON levels of 0.2, 0.5, and 1.0 ppm. Pelleted diets were fed 3 times daily until satiation to Pacific white shrimp Liropenaeus vanna‐mei. Biological performance (live weight, weekly growth increment, feed conversion ratio, and survival) was determined biweekly for 16 wk. Histological characteristics of shrimp were determined on samples obtained after 8 and 16 wk of growth. The DON levels in ground wheat, feed mash, pellets, and freeze‐dried shrimp were determined using thin layer and high performance liquid chromatography. Deoxynivalenol levels of 0.2, 0.5, and 1.0 ppm in the diet significantly reduced shrimp body weight and/or growth rate. However, the effects of 0.2 and 0.5 ppm DON were manifested at later stages of shrimp growth, and 0.2 ppm DON significantly affected only growth rate and not body weight (P > 0.05). Feed conversion ratio and survival of shrimp fed diets containing 0.2, 0.5, and 1.0 ppm DON were not significantly different from those of shrimp fed the control diet (0.0 ppm DON). After 16 wk of growth, no DON was detected in freeze‐dried shrimp, and no consistent difference was observed in the histological organ profiles of shrimp fed diets containing various levels of DON. Because low levels of DON in the diet can significantly reduce body weight and growth rate of shrimp, feed ingredients should be monitored for DON.
Occurrence of the Enigmatic, Unicellular Psorospermium Organism in Several Cultured, Sympatric Populations of the Freshwater Crayfishes Procambarus clarkii and Procambarus zonangulus
Authors: Klarberg David P. , Henttonen Paula , Huner Jay V.
Published: April 2007

The parasitic Psorospermium organism was studied in cultured sympatric populations of mature Procambarus clarkii and Procambarus zonangulus during four consecutive annual crayfish seasons from 1991–1992 through 1994–1995. Most P. clarkii were infected while fewer than half of the P. zonangulus were infected throughout the study period. The numbers of Psorospermium were four to eight times greater in P. clarkii and showed annual changes not seen in P. zonangulus. Both crayfishes demonstrate 1yr life cycles in Louisiana and this seemed to explain the variations seen in Psorospermium dynamics in the two hosts. In general, there was no consistent association between crayfish size and the number of parasites found in them for either crayfish species. There was some indication of an association between the presence of infection and the number of parasites found in P. zonangulus.
Effect of Environmental Factors on Development of Rotifer and Copepod Nauplii Populations in Sunshine Bass Morone chrysops×M. saxatilis Nursery Ponds without Fish
Authors: Ludwig Gerald M.
Published: April 2007

Knowledge of the effect of environmental factors on timing and production of zooplankton populations would enable sunshine bass Morone chrysops×M. saxatilis farmers to stock fry when live food is most available and thereby increase fry survival. Relationships of morning water temperature, morning and average daily air temperature, day length, number of rain days and daily rain fall, and dissolved oxygen concentrations to time required for rotifer and copepod nauplii populations to peak in freshly filled freshwater nursery ponds was determined. Relationships of the same independent variables to concentrations of rotifers and copepod nauplii at the peak were also determined. For rotifers, day length, dissolved oxygen, and water and air temperatures were highly correlated with time to the peak density, but not concentration of rotifers. Time required for copepod nauplii densities to peak was associated with rain events; whereas, nauplii concentration was related to day length, dissolved oxygen levels and, to a lesser extent, water and air temperatures. Regression equations of the independent variables had very low predictive value for rotifer or nauplii densities or time to reach initial peak nauplii populations. Regressions of day length, morning water temperature, morning and average daily air temperature had moderate values (r2 > 0.7) for predicting time to initial peak rotifer densities.
Economic Feasibility of Aquaculture of Spiny Lobsters Jasus edwardsii in Temperate Waters
Authors: Jeffs Andrew , Hooker Simon
Published: April 2007

Around the world there is strong interest in the aquaculture of spiny lobsters (family Palinuridae). However, there is little published information about the economic feasibility of spiny lobster aquaculture. For more than 20 yr there has been experimental grow out of the spiny lobster Jasus edwardsii in New Zealand in land‐based systems using seed animals (puerulus) taken from the wild. These studies provide sufficient information on growth, mortality, food conversion, handling and capital costs to enable an assessment of the economic feasibility of the commercial culture of spiny lobsters in temperate waters. This assessment suggests that profitable spiny lobster aquaculture will rely on greatly reducing the infrastructure and operating costs of land‐based farming operations, as well as lowering feed and labor costs. Financial simulations suggest that increasing productivity through faster growth rates and lowered culture mortalities will only have a minor effect on profitability unless infrastructure and operating costs can be reduced significantly. Seacage culture or sea ranching of spiny lobsters may offer a means of avoiding high infrastructure costs associated with land‐based farming operations. The development of a cost‐effective artificial feed would also appear to be a priority for improving the economic outlook for culturing spiny lobsters. The results of this study are relevant to the economics of spiny lobster culture developments in other temperate regions of the world.
Concentration of 17α‐Methyltestosterone in HormoneTreated Feed: Effects of Analytical Technique, Fabrication, and Storage Temperature
Authors: Teichert‐Coddington David , Manning Bruce , Eya Jonathan , Brock David
Published: April 2007

Feed treated with 17α‐methyltestosterone (MT) is used to manipulate the gender of early tilapia fry. In the USA, hormone‐treated feed is used by selected producers under an Investigational New Animal Drug (INAD) program. While monitoring the fabrication and on‐farm use of this treated feed, concerns were raised about the high performance liquid chromatography (HPLC) analytical procedure for detecting MT in feeds, the incorporation of MT in feeds during fabrication, and effects of storage temperature on MT concentration. A series of experiments demonstrated that the analytical procedure for detecting MT in feeds lacked high precision, and, on average, biased results low. MT was uniformly mixed with feed by spraying an MT‐alcohol solution on feed while it was blended in an industrial ribbon mixer. Alcohol volumes ranging from 15 mL/kg to 150 mL/kg were equally effective at dispersing MT in feed. The concentrations of MT in feeds consistently declined over time if the storage temperatures were 25 C or higher. Freezing preserved the MT in feed, and the refrigeration of feed fabricated to contain 60 mg MT/kg maintained acceptable MT concentrations during 6 mo of storage.
Observations and Techniques for Maturation, Spawning, and Larval Rearing of the Yellowtail Snapper Ocyurus chrysurus
Authors: Turano Marc J. , Davis D. Allen , Arnold Connie R.
Published: April 2007

Abstract.— This paper describes current techniques used at our laboratory for the controlled spawning, maturation and larval rearing of the yellowtail snapper. Juvenile yellowtail snapper were obtained from Florida and transferred to the Fisheries and Mariculture Laboratory in July 1990. Temperature and photoperiod manipulation resulted in precocial spawning in 1991, with sustained successive spawning beginning in February 1992. Average weekly spawning from 1992–1994 was 308,000 and 247,000 eggs/tank, with fertilization rates of 46.1 % and 32.5% for fish maintained in two separate spawning tanks. Observations on spawning activity from 1995 to 1996, during which a decreasing trend in egg and larval quality was observed, imply a possible problem with broodstock nutrition. Evaluation of feeding regimes during this period indicated a shift to a high (almost exclusively) usage of fresh squid and a reduction in fish and shrimp. Returning to a feeding regime of alternating feedings of fresh fish, squid. and shrimp have yielded improved spawning and egg quality. Larval rearing techniques using live and prepared feeds has resulted in an overall survival of 3% from egg to advanced juvenile. Growout of first generation (F1) juveniles yielded a marketable size (1 1b) fish in 25 mo. Spawning of F1 fish hegan in 1998. larval rearing and grow out of F2 fish are currently underway. Results demonstrate that yellowtail snapper culture is technically feasible; however. further research to develop species specific culture techniques will be required before the culture potential of this species can be accurately evaluated.
Effects of Lighting Spectrum and Disturbance Level on the Growth and Stress Responses of Yellow Perch Perca flavescens
Authors: Head Alex B. , Malison Jeffrey A.
Published: April 2007

Abstract.— We evaluated the effects of different lighting spectra and routine disturbances on the growth and stress responses of yellow perch Perca, flavescens. Fish were reared in tanks under one of three different lighting spectra: blue (405–530 nm), red (600–750 nm). or full spectrum (380–750 nm). For each lighting spectrum, fish were reared under one of two disturbance levels: one in which the fish were exposed to 2–4 daily routine disturbances which typify intensive tank culture conditions (e.g., casting shadows over the tank, sham tank siphoning, and dissolved oxygen measurement: ‘disturbed’). or a second treatment in which such disturbances were minimized (‘undisturbed’). The fish were reared for 87 d under temperature, photoperiod. and feeding conditions near optimal for the growth of yellow perch. The cortisol stress response of the different fish groups was evaluated by measuring baseline serum cortisol levels on days 0, 1,3, and 21, and by measuring cortisol levels 30 min after the application of an acute handling stressor on days 0, 1, and 3. Treatment effects on growth were measured from days 21–86 of the study. On day 87, various organs and parameters were evaluated to compare the health and condition of fish reared under the different treatments. Disturbed fish gained less weight and length, and had a significantly lower condition factor than undisturbed fish. Additionally, the disturbed fish showed no signs of acclimation to the frequent disturbances. The fish under red and full spectrum light gained more length than those under blue light. Frequent disturbance had a greater negative effect on length gain in fish reared under red light than in those reared under the other light treatments. On day 21, but not on other days, baseline cortisol levels were higher in disturbed than in undisturbed fish. Undisturbed fish had higher levels of mesentery fat than disturbed fish. Our results demonstrate that yellow perch growth can be significantly affected by disturbance level and lighting conditions. These factors should be taken into consideration when developing culture strategies to maximize the growth of yellow perch reared under intensive culture conditions.
Dry‐Tilling of Pond Bottoms and Calcium Sulfate Treatment for Water Quality Improvement
Authors: Seo Jinwon , Boyd Claude E.
Published: April 2007

Three different pond bottom treatments were evaluated in 12 earthen ponds. Bottoms of four ponds on the Auburn University Fisheries Research Unit, Auburn, Alabama, were dried for 1 mo and tilled with a roto‐tiller (dry‐till treatment). Four other ponds were dried and tilled, and after filling with water, enough gypsum (calcium sulfate) was applied to give a total hardness of about 200 mg/L. Gypsum was reapplied as needed to maintain the hardness (dry‐till with gypsum treatment). Four ponds were not subjected to bottom drying, tilling or gypsum treatment (controls). Channel catfish Ictalurus punctatus fingerings were stocked at 15,000/ha. Selected water quality variables were measured at 1‐ to 2‐wk intervals during the growing season. Concentrations of most variables increased over time because feeding rate was increased progressively as fish grew. Compared to the controls, both treatments had lower concentrations of total phosphorus and soluble reactive phosphorus, and higher concentrations of dissolved oxygen (P < 0.05). In addition, ponds of the dry‐till with gypsum treatment had in addition lower concentrations (P < 0.05) of chlorophyll a, chemical oxygen demand, gross primary productivity, and total alkalinity than control ponds. The reduction in chlorophyll a concentration suggested less phytoplankton in gypsum‐treated ponds, and this effect was probably related to lower phosphorus availability because of calcium phosphate formation. Secchi disk visibility, total suspended solids concentrations, and turbidity did not differ significantly among the treatments (P < 0.05). Total fish production and survival rate did not differ significantly (P < 0.05) among the treatments. These findings suggest that water quality improvement can be achieved by drying and tilling pond bottoms between crops, and benefits possibly may be increased by treating low hardness waters with gypsum.
Growth and Survival of the Blood Ark Anadara ovalis (Bruguière, 1789) Cultured in Mesh Bags on Soft‐Bottom Sediments in the Coastal Waters of Georgia
Authors: Power Alan J. , Walker Randal L.
Published: April 2007

Annual growth and survival rates were measured for blood arks Anadara ovalis (Bruguière 1789) cultured in mesh bags that were placed at the spring‐low‐water mark in soft‐bottom sediments of the Skidaway River, Georgia. The feasibility of growing the arks to a marketable size using this technique was assessed by determining the effects of stocking density and biofouling on growth and survival. Two replicate densities of 190 (low) and 400 (high) arks per mesh bag (mean shell length 31.97 mm) were planted in early September 1999. In April 2000, the arks cultured at the lower density had a significantly larger size (44.99 mm) than at the higher density (43.83 mm), with growth rates of 1.85 mdmo, and 1.69 mm/mo, respectively. Growth decreased considerably in the subsequent months (low: 0.17 mm/mo; high: 0.30 mm/mo). There was no significant difference in ark size between treatments after a year's growth in late August 2000 (low: 45.76 mm, 1.15 mm/mo; high: 45.31 mm, 1.11 mm/mo). Similarly, no significant difference in annual survival rates between stocking densities occurred (low: 42.89%; high: 40.25%). The present findings indicate that this method of growing arks to market size has potential to contribute to future endeavors to develop an aquaculture fishery for the blood ark in the coastal waters of Georgia.
Prevalence of Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) and White Spot Syndrome Virus (WSSV) in Litopenaeus vannamei in the Pacific Ocean off the Coast of Panama
Authors: Nunan Linda M. , Arce Steve M. , Staha Ronald J. , Lightner Donald V.
Published: April 2007

Abstract.— In March 2000, 104 wild caught Litopenaeus wannamei broodstock, captured off the Pacific coast of Panama, were screened for the following penaeid viruses: infectious hypodermal and hematopoietic necrosis virus (IHHNV) and white spot syndrome virus (WSSV). The purpose of this study was to determine the prevalence of IHHNV and WSSV in wild shrimp in this area of the Western Hemisphere and to acquire specific pathogen free (SPF) L. vannamei for inclusion into the Oceanic Institute's genetic breeding program. The prevalence of the viruses was determined using the dot blot hybridization format, which is a commercially available molecular method for detecting these viruses. Dot blot hybridization assays can be used as an initial screening method to detect moderately to highly infected shrimp. The results from the dot blot assays indicated the prevalence of IHHNV in 28% and WSSV in 2% of the 104 hemolyrnph samples tested. Results from this study were used to establish the initial candidate SPF status of the animals that were assessed and to determine the prevalence of two serious pathogens of penaeid shrimp captured from the wild of the Pacific Ocean in the Central American region off the coast of Panama.
Waveform Selection for an Electrically Enhanced Seine for Use in Harvesting Channel Catfish Ictalurus punctatus from Ponds
Authors: McDill Kenneth K. , Minchew C. Douglas
Published: April 2007

Abstract.— A series of rapid screening trials was used to identify a waveform with the potential to repel channel catfish Ictalurus punctarus away from a seine. Waveforms were not considered effective unless they repelled catfish away from an advancing electrical array without causing electrotaxis, narcosis, or observable injuries. Over 600 varying combinations of waveform types, voltages, pulse frequencies, pulse widths, and pulse sweeps were evaluated in order to select the best waveform for use in constructing an electrically enhanced seine. A number of electrode designs were evaluated to determine the most efficient and effective electrode combination, size, and configuration to use in the screening trials. In studies conducted in concrete vats, harvest efficiencies (the percentage offish present that were captured) greater than 92% were achieved using a low to high frequency waveform with a 6.0–60 Hz sweep and a 2 msec pulse width over a 4 sec sweep time. This waveform was selected for use in the construction of an electrically enhanced seine that will be used in future pond harvest studies.
The Effect of Temperature on First Feeding, Growth, and Survival of Larval Witch Flounder Glyptocephalus cynoglossus
Authors: Bidwell Deborah A. , Howell W. Huntting
Published: April 2007

Witch flounder Glyptocephalus cynoglossus has recently been identified as a candidate species for aquaculture in the northeastern United States and the Canadian Atlantic Provinces. This study investigated the optimal temperatures for witch flounder larval first feeding and for long term larval culture from hatching through metamorphosis. Maximum first feeding occurred between 15.0 and 16.2 C. Larvae did not survive beyond first feeding when reared at mean temperatures of 5.1, 10.4, or 19.5 C and were unable to initiate feeding at mean rearing temperatures below 6.0 C. At a rearing temperature of 15.0 C in 16‐L tanks, mean larval survival to 60 days post hatch (dph) was 14.1%. Mean overall length‐specific growth rate for larvae reared to 60 dph at 15.0 C was 3.5%/d and mean absolute growth was 0.62 mm/d. Subsequent larval growth at 15.6 C began to taper off towards 70 dph at the onset of weaning which overlapped with larval metamorphosis. Growth plateaued at 85 dph, followed by a rebound between 90 and 95 dph. Survival was 100% when weaning onto a dry, pelleted diet was initiated at 70 dph with a 10‐d live diet co‐feeding period. These results are favorable and encourage the further pursuit of commercial witch flounder culture.
Toxicity of Hydrogen Peroxide to Pre‐exposed Young‐of‐the‐Year Walleye: Effects of Water Hardness and Age of Fish
Authors: Tripi Christopher , Bowser Paul R.
Published: April 2007

Abstract.— Young‐of‐the‐year (Age 0+) walleyes Stizostedion vitreum were exposed to hydrogen peroxide at 10 mg/L for 1 h in an effort to increase their tolerance to subsequent exposures to hydrogen peroxide at therapeutic concentrations that are considered to be toxic. The effects of age of fish and water hardness on the effectiveness of this pre‐treatment protocol were examined. Trials were performed in fish at four ages (50‐d, 60‐d, 86‐d, and 95‐d post‐hatch) and under three different water quality conditions (soft water: hardness = 64.4 mg/L, alkalinity = 56.5 mg/L; medium hard water: hardness = 103.3 mg/L, alkalinity = 51.5 mg/ L; hard water: hardness = 130.3 mg/L, alkalinity = 92 mg/L). A benefit of pre‐treatment was only observed when it was performed under hard water conditions and only with walleyes at 60‐ and 86‐d post hatch. The pre‐treatment protocol appeared to be detrimental to fish in the youngest age group (50‐d post‐hatch) under all three water quality conditions.