bluuebunny/crossref_metadata_2025 huggingface dataset:
Preliminary Observations on the Reproductive Physiology of Female Orangemouth Corvina in Captivity
Authors: Thomas Peter , Copeland Paul A. , Prentice John A.
Published: April 2007

Seasonal changes In oocyte growth and plasma estradiol, testosterone, thyroid hormones and vitellogenin levels were monitored in three captive adult female orangemouth corvina Cynoscion xanthulus subjected to a condensed (8 mo) seasonal cycle of photoperiod and water temperature. Plasma concentrations of estradiol and testosterone began to rise when temperature increased to 28 C and photoperiod to 15 h light (midsummer conditions). This was accompanied by elevated circulating levels of vitellogenin and the appearance of vitellogenic oocytes (diameter > 100 μm). Estradiol concentrations and mean oocyte size increased concurrently during late summer conditions and were maximum during fall conditions, approximately 8 wk after the beginning of ovarian recrudescence. In contrast, plasma levels of thyroid hormones did not show any distinct seasonal changes. Gonadally recrudesced females contained several size classes of vitellogenic oocytes. Injection of these fish with a luteinizing hormone‐releasing hormone analog (LHRHa) caused maturation and spawning of the largest oocytes (mean diameter of follicles × 2500 μm). Another group of vitellogenic oocytes had been recruited into this size class by 2 wk after the end of spawning, which suggests that this species is capable of repeated spawning during the reproductive season. Injection of LHRHa resulted in increased plasma levels of gonadotropin and repeated spawning over several days. LHRHa‐induced final oocyte maturation, ovulation and spawning were preceded by increases in plasma levels of two teleostean maturation‐inducing steroids, 17α,20β, 21‐trihydroxy‐4‐pregnen‐3‐one (20β‐S) and 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (17α,20β‐P4). The results provide preliminary evidence that oocyte growth is stimulated in orangemouth corvina subjected to an abbreviated seasonal cycle in captivity under midsummer photoperiod and temperature conditions and is associated with seasonal increases in plasma estradiol concentrations and vitellogenin production. However, the relative importance of 20β‐S versus 17α, 20β‐P4 in the control of final oocyte maturation in this species could not be determined from the results of the present study.
A Survey of Trout Fin Erosion, Water Quality, and Rearing Conditions at State Fish Hatcheries in Utah
Authors: Bosakowski Thomas , Wagner Eeric J.
Published: April 2007

A total of 600 hatchery trout were examined for signs of fin erosion including rainbow trout Oncorhynchus mykiss, cutthroat trout O. clarki, brook trout Salvelinus fontinalis and brown trout Salmo trutta. A scoring system was used to evaluate erosion on all fins from 20 fish samples. Water quality and hatchery rearing variables were also determined for corresponding raceways or ponds. For rainbow trout groups (N= 24), stepwise multiple linear regression was used to interpret the relationship between fin erosion and the other variables. These fish groups averaged between 92 and 243 mm in total length and no significant correlation was observed between length and a fin erosion index (r = 0.045). The best‐fit regression model (adjusted R2= 0.689) suggested that fin erosion was correlated with lower alkalinities, unnatural bottom substrates (concrete or steel), higher unionized ammonia levels, and higher fish densities. Despite significant variation between hatcheries, fin condition was significantly better in rainbow trout than in cutthroat trout in three of four hatcheries containing both species and the same substrate. Fin erosion in rainbow trout occurred primarily on dorsal fins, followed in order of decreasing severity, by pectoral, caudal, anal, and ventral fins.
Toward Coordination and Funding of Long‐Term Genetic Improvement Programs for Striped and Hybrid Bass Morone sp.
Authors: Hallerman Eric M.
Published: April 2007

The productivity and profitability of striped and hybrid bass Morone sp. aquaculture would be enhanced by genetic improvement of cultured stocks. To date, genetic improvement of cultured bass stocks largely has been limited to interspecific hybridization and ploidy manipulation, techniques which are aimed at short‐term genetic gains. Upon domestication, long‐term improvement of striped or hybrid bass can be approached. Lines of striped bass and other Morone species can be selected for rapid growth, stress tolerance, disease resistance, combining ability, or other traits. Improved lines can be crossed to produce superior hybrids or crossbreds, or manipulated to produce superior triploid or transgenic stocks. Current breeding projects are limited in size, and coordination of breeding activities among groups would be advantageous. Faced with the likelihood of limited government funding, long‐term genetic improvement of Morone species might be supported by the industry through a fund receiving a small percentage of the proceeds from sales of cultured Morone products.
Pond Bottom Soil Respiration during Fallow and Culture Periods in Heavily‐Fertilized Tropical Fish Ponds
Authors: Boyd Claude E. , Teichert‐Coddington David
Published: April 2007

Benthic respiration in two fish culture ponds at Comayagua, Honduras, was below 1g CO2/m2per day during culture periods. When ponds were drained for fish harvest, bottom soils were exposed to the air, and soil respiration rates as high as 10g CO2/m2per day were recorded. High rates of soil respiration following removal of saturated conditions declined as labile organic matter was consumed and soil moisture content declined. Laboratory studies showed that the moisture content greatest for soil respiration was near saturation, and either drying soils or completely saturating them drastically reduced respiration. Although soil respiration rates were much greater during the fallow period than during the culture period, more organic matter was decomposed during the culture period because it was much longer (5 months) than the fallow period (2 weeks).
Effects of Dietary Vitamin C on Maturation and Egg Quality of Cod Gadus morhua L.
Authors: Mangor‐Jensen Anders , Holm Jens Chr. , Rosenlund Grethe , Lie ØOsyvind , Sandnes Kjartan
Published: April 2007

The effects of dietary vitamin C on maturation and egg quality of cod Gadus morhua L. have been investigated. The broodstock groups were fed three different levels of vitamin C mixed into a commercial dry pellet. The experimental feeding started three months prior to the spawning season. Naturally spawned eggs were collected and analyzed with regard to viability, biochemical composition and physical characteristics. Differences in free amino acid profile, egg strength and neutral buoyancy were found, whereas no effects on vital parameters, such as fertilization rate and survival rate, were detected.
Vibriosis of Swimming Crab Portunus trituberculatus in Larviculture
Authors: Muroga Kiyokuni , Sszuik Kouji , Ishimaru Kkatswa , Nogami Kinya
Published: April 2007

Since 1985, frequent mass mortalities due to a bacterial infection have occurred in zoeal larvae of swimming crab Portunus trituberculatus reared at the Tamano Station of the Japan Sea‐Farming Association. A bacterium was predominantly isolated from diseased larvae and was demonstrated by experimental infection to be the causative agent of the disease. Based on morphological, physiological, biochemical, serological and genetic characteristics of the pathogen, it was thought to be a new species and tentatively named Vibrio sp. Zoea. Challenge experiments with the bacterium in several aquatic animals indicate that Vibrio sp. Zoea appears to be a pathogen specific for crustaceans.
Effects of Size‐Grading on Variation and Growth in Channel Catfish Reared at Similar Densities
Authors: Carmichael Gary J.
Published: April 2007

Channel catfish Ictalurus punctatus obtained from two spawns were size‐graded into four weight groups: large, mean = 92.4 g ± 0.9 SE; medium = 64.2 ± 0.5; small = 36.1 ± 0.5; and communal = 49.0 ± 2.0 (a combination of large, medium, and small fish). Twelve indoor 643 L rearing units were stocked with the four size‐graded groups at initial densities (but different numbers of fish) of 3.12 g offish per L water and were fed for 66 d at 3% of biomass daily. At harvest the final densities (mean = 9.95 g/L) were equal in all rearing units. Survival and feed conversion were similar among the size‐groups. Initial Coefficients of variation for weight were significantly different among the size‐graded group as large < medium < small < communal. Final coefficients of variations were significantly greater than initial values in the large, medium, and small size‐graded group and were less in the communal group. Gain, survival, and coefficient of variation relationship within the communally stocked rearing units were similar to those for separately reared groups. Final coefficients of variation were greater (210, 204, and 115%) or less (89%) than initial values for large, medium, small, and communal groups, respectively, and indicate a repnrtitioning of variation, perhaps due to altered feeding behavior or social hierarchical order.
Evaluation of Omega‐3 Fatty Acid Enrichment of Artemia Nauplii as Food for Striped Bass Morone saxatilis Walbaum Larvae
Authors: Oozkizlick Sureyya , Chu Fu‐Lin E.
Published: April 2007

Three enrichment techniques were evaluated for their efficiency in improving the dietary value of Artemia nauplii to striped bass larvae. Newly hatched Artemia nauplii from the Great Salt Lake (GSL) were enriched for 24 h using the following diets: 1) gelatin‐acacia microcapsules containing menhaden oil rich in omega‐3 polyunsaturated fatty acids (PUFA), primarily 20:5ω3 eicosapen‐taenoic acid; 2) an emulsion of Baker's yeast and menhaden oil; and 3) marine Chlorella sp. Unfed San Francisco Bay (SFB) and GSL nauplii were used as controls. Enriched GSL (all three diets) and unfed SFB nauplii had significantly higher (P < 0.05) levels of 20:503 than the unfed nauplii from GSL. Seven days post‐hatched (day 0) striped bass larvae were reared for 21 d on enriched or unfed nauplii. On day 21, wet weight and total length of striped bass larvae fed enriched GSL nauplii and unfed SFB nauplii were significantly greater (P < 0.05) than those fed unenriched GSL nauplii. The enrichment of the GSL nauplii appeared to increase the eicosapentaenoic acid content and enhance the growth of the striped bass larvae.
Effects of Stocking Density and Feed on Pond Production Characteristics and Revenue of Harvested Freshwater Prawns Macrobrachiurn rosenbergii Stocked as Size‐Graded Juveniles1
Authors: Daniels William H. , Dabramo Louis R. , Fondren Mack W. , Durant Martin D.
Published: April 2007

A nursery‐reared population of juvenile freshwater prawns (Macrobrachium rosenbergii) averaging 0.11 ± 0.058 g was size graded through a 4‐mm bar grader producing a numerically 53% upper size population (0.25 ± 0.086 g). These were stocked into triplicate earthen ponds (0.04–0.07 ha each) at densities of 39,540, 59,300 and 79,100/ha, grown for 131 to 134 d, and fed a specially formulated diet. An additional three ponds were stocked at 39,540/ha and fed a commercial sinking catfish feed. Density had a significant effect on average whole body wet weight at harvest but no significant effect on either total yield, survival, or feed conversion. Mean wet weight was significantly higher for prawns stocked at 39,540/ha (34.3 g) than that for those stocked at either 59,300/ha (26.7 g) or 79,100/ha (263 g). The direct relationship between the percentage of small males and increasing density usually seen with ungraded populations was not evidenced in the size‐graded populations. Average total yield ranged from 1,041 to 1,662 kg/ha for stocking densities from 39,540 to 79,100/ha. Differences in overall mean wet weight resulted from differences in mean wet weights for orange claw and no claw males and berried and open females, not from differences in morphotype distributions. These differences resulted in significantly higher percentages of tails within the larger count categories and higher revenues for prawns stocked at 39,540/ha. Feed type had no significant effect. Projected net revenues suggest that prawns need to be marketed and sold as a whole product.
Tolerance to Formalin by a Fluidized‐Bed Biofilter and Rainbow Trout Oncorhynchus mykiss in a Recirculating Culture System
Authors: Heinen John M. , Weber Amy L. , Noble Alicia C. , Morton Joseph D.
Published: April 2007

Formalin tolerances of a fluidized‐bed sand biofilter and rainbow trout Oncorhynchus mykiss were tested in a semi‐closed freshwater recirculating culture system. Progressively higher formalin levels were tested until fish mortality (±1.9%) occurred. A 1‐h exposure to 167 ppm formalin, followed by flushing, was safe for trout (no mortality) at 15.0 C but not at 16.5 C. A 110‐ppm indefinite treatment (no flushing) was safe at 17.3 C, but 120 ppm at 17.3 C and 100 ppm at 17.8 C were not. Biofilter nitrification was not impaired by 1‐h formdin treatments up to 167 ppm at 16.5 C, and not, usually, by indefinite treatments up to 120 ppm at 17.3 C. However, a find indefinite treatment of 70 ppm was followed by abnormally high nitrite levels for 9 d. Formaldehyde remained detectable in the system for 11 h during indefinite treatment at 120 ppm formalin. Tests on the system's Co2 stripper did not indicate that it removed formaldehyde.
Effects of Water Temperature, Density, and Sex Ratio on the Spawning Rate of Red Claw Crayfish Cherax quadricarinatus (von Martens)
Authors: Yeh Hsin Sheng , Rouse David B.
Published: April 2007

Effects of water temperature on red claw crayfish Cherax quadricarinatus spawning rates was evaluated for 3 mo at 22, 26 and 30 ± 1 C. A 20/m2 stocking density and a 1:2 M: F sex ratio was used. Spawning rate increased as temperature increased, with 30 C providing the highest spawning rate (P < 0.05). Effects of stocking density and sex ratio on the reproduction of red claw crayfish were also evaluated at densities of 10.15 and 20/m2, with a sex ratio of 1:1, and at three sex ratios (1:1. 1:3 and 1:5 M: F) at a density 10/m2. Water temperature was maintained at 28 ± 1 C and photoperiod was maintained at 14L: 10D for 6 mo during the density and sex ratio experiments. Spawning rates were not significantly different (P > 0.05) within the three stocking densities at a sex ratio of 1:1, nor were they different (P > 0.05) for the three sex ratios at a density of 10/m2. Results revenled that densities as high as 20/m2 and sex ratios of 1 male to 5 females can be used to increase spawning per tank. Also, high temperature (28 ± 1 C) and long day lengths (14L: 10D) can be utilized to stimulate peak spawning rates, but high spawning rates cannot be maintained for more than about 3 mo.
Dietary Threonine Requirement of Juvenile Red Drum Sciaenops ocellatus
Authors: Boren R. Scott , Gatlin Delbert M.
Published: April 2007

Threonine is an indispensable amino acid required by all animals for normal growth and metabolic functions. An experiment was conducted in a brackish water (5 ± 1 ppt) recirculating system to quantify the minimum dietary threonine requirement of juvenile red drum Sciaenops ocellatus. The experimental diets contained 350/0 crude protein from red drum muscle and crystalline amino acids and 3.2 kcal available energy/g diet. Incremental levels of L‐threonine were added to the diets and fed to juvenile red drum initially averaging 2.8 g/fish for 8 wk. Weight gain and feed efficiency of fish fed the various diets were significantly (P < 0.05) affected and increased linearly as dietary threonine increased until plateauing around 0.8% of dry diet. Protein efficiency ratio and protein conversion efficiency values for fish fed the different diets also were significantly affected by threonine level and indicated requirement values of 0.8–0.9% of dry diet. Free threonine in plasma also significantly responded to increasing dietary threonine but indicated a slightly higher requirement value of approximately 1.0% of dry diet. Based on these data, the minimum threonine requirement of juvenile red drum was determined to be approximately 0.8% of dry diet (2.28% of dietary protein). This requirement level is similar to values reported for some other fish species. Based on this information diets may be formulated more precisely for aquacultural production of red drum.
The Cost of Off‐Flavor
Authors: Engle Carole R. , Pounds Gayle L. , van der Ploeg Martine
Published: April 2007

Off‐flavor problems in farm‐raised catfish Ictalurus punctatus increase production costs and pose inventory management problems for catfish farmers. Multiperiod mathematical programming techniques were used to test the effect of 16 different off‐flavor scenarios on expected net returns above variable cost with and without cash flow restrictions. The patterns of off‐flavor incidence had less effect on farm profits than whether or not fish are off‐flavor during certain key months of the year. To be feasible, systems designed to purge off‐flavor from catfish would need to cost less than $0.05 to $0.06/kg (if cash flow is not a consideration) or $0.04/kg to $0.25/ke (with cash flow considerations).
Assessing Noxious Phytoplankton in Aquaculture Systems Using Bio‐Optical Methodologies: A Review
Authors: Millie David F. , Schofield Oscar M. , Dionigi Christopher P. , Johnsen Peter B.
Published: April 2007

Management practices in aquaculture systems contribute to maximum growth of phytoplankton, often resulting in extensive blooms of noxious cyanobacteria. Because periods of oxygen depletion and “off flavor” events correspond to intense algal growth and metabolic activity, accurate identification of algal dynamics and physiological state is important. Current efforts to assess algal assemblages rely upon microscopic evaluation; however, the incorporation of such evaluation into monitoring programs is limited due to the level of skill and training required, the excessive costs and time required to assess algal heterogeneity within/among aquaculture systems, and the lack of information provided concerning physiological state. The distinct biwptical characteristics of the blooms lend themselves to pigment‐based methodologies (pigment and in vivo absorption “signatures”, chlorophyll a fluorescence, multi‐spectral remote sensing) which complement microscopic evaluation and can be implemented into large‐scale monitoring programs. For example, because the key ingredient for success of such programs is the rapid, reliable, and accurate characterization of algal biomass along variable temporal/spatial scales, remotely‐sensed data acquisition most likely will be required. High‐performance liquid chromatography (HPLC)‐derived pigment and in vivo absorption “signatures” can delineate problematic algal phylogenetic groups and physiological states. Further, measurements of chlorophyll a fluorescence provide estimates of phytoplankton absorption, quantum efficiency, and potentially production potential and growth rate. As such, they can be used to confirm the systematic significance of remotely‐sensed data. It would be highly desirable to integrate an evaluation program using bio‐optical methodologies into a geographic information system to allow for integrating, modeling, and predicting parameters of management interest over the scales relevant to aquacultural and water resource management.
Effects of Dietary Protein Concentration on Growth, Survival, and Body Composition of Muskellunge Esox musquinongy and Tiger Muskellunge Esox masquinongy × E. luscius Fingerlings
Authors: Brecka Brian J. , Kohler Christopher C. , Wahl David H.
Published: April 2007

Growth rate, survival and body composition of muskellunge Esox musquinongy (initial mean total length = 125 mm) and tiger muskellunge E. masquinongy × E. lucius (initial mean total length = 115 mm) fed semi‐purified diets differing in protein level from 31 to 40% and 34 to 45%, respectively, were evaluated in 8‐wk trials. The minimum protein level that yielded satisfactory growth rates for muskellunge was 37%, whereas tiger muskellunge growth rates were highest for fish fed a 45% protein diet. Growth differences were caused by changes in protein quantity, not quality, as amino acid ratios were similar for test diets and showed no imbalances among diets. Condition factors for both fishes increased with dietary protein. Survival of muskellunge (73%) and tiger muskellunge (97%) was not pffected by diet type. Body protein increased and fat content decreased in both fishes when fed higher dietary protein. Results suggest that both fishes respond similarly to dietary changes, but that substantial differences exist in protein requirements.
Effect of Satiate or Restricted Feeding on Golden Shiner Notemigonus crysoleucas Production in Earthen Ponds
Authors: Rowan Martha , Stone Nathan
Published: April 2007

Abstract.— This study was conducted to evaluate the effects of satiate or restricted feeding on the growth and production of golden shiners Notemigonus crysoleucas. Golden shiners (1.2 g) stocked at 560 kg/ha in 12,0.04‐ha earthen ponds for 79 d grew to average weights of 5.6, 4.6 and 3.8 g for fish fed to satiation, or 75% or 50% of that amount, respectively. Gross yield ranged from 811 to 1,277 kg/ha; net yield did not differ significantly among treatments.
Effects of Temperature on Growth and Protein Assimilation in Juvenile Leader Prawns Penaeus monodon
Authors: Deering M. J. , Fielder D. R. , Hewitt D. R.
Published: April 2007

Abstract.— The effects of temperature on growth and protein assimilation in leader prawns Penaeus monodon were evaluated. Growth of leader prawns was significantly (P < 0.05) affected by temperature. The highest growth rate was 0.124 g/d at 32.0 C and optimum growth occurred between 27.5–32.0 C. Growth was described by an equation of the form: Wt= Woekt (R2= 0.99). The relationship between temperature and growth was described by a curvilinear equation of the form: Y = a + bX + cX2 (R2= 0.70). Apparent protein assimilation efficiency was not significantly (P > 0.05) affected by temperature.
The Aerobiological Pathway of a Fish Pathogen: Survival and Dissemination of Aeromonas salmonicida in Aerosols and its Implications in Fish Health Management
Authors: Wooster Gregory A. , Bowser Paul R.
Published: April 2007

The aerobiological (aerosol) pathway of Aeromonas salmonicida subspecies salmonicida (ATCC 33658) was investigated. Results indicate that viable A. salmonicida can travel as an aerosol/droplet spray at least 104.1 cm (limits of the test chamber used) when carried by air currents. Additionally, viable A. salmonicida was recovered from water exposed to an experimentally generated aerosol/droplet spray of A. salmonicida downwind from the contaminant source. It is possible that viable bacterial aquatic animal pathogens can be spread via the airborne route. This possible route of pathogen introduction could effect current management or system designs, especially when aquaculture systems consist of tanks in close proximity.
Weaning of Wild Young‐of‐the‐Year Winter Flounder Pleuronectes americanus (Walbaum) on a Dry Diet: Effects on Growth, Survival, and Feed Efficiency Ratios
Authors: Lee Gillian W. Y. , Litvak Matthew K.
Published: April 2007

Winter flounder Pleuronectes americanus is being developed for aquaculture in Atlantic Canada. Weaning, the switch from a live diet to formulated feed, is a critical stage in the culture of any fish species. In this study, we used wild young‐of‐the‐year stock to determine whether juvenile winter flounder can be weaned from live, cultured Artemia onto dry feed. The dry feed used was originally formulated for turbot Scophthalmus maximus and cod Gadus morhua by BP Nutrition, Stavanger, Norway. The performance of live feed and dry pellets was compared in terms of survival, growth and feed efficiency over three months. We were able to wean wild juvenile winter flounder onto dry feed after one week. Increased specific growth rates and feed efficiency ratios in weaned juveniles indicated that prepared diet was a better food source than Anemia. Survival was not influenced by food type.
Use of High Oleic Corn in Catfish Feeds
Authors: Sugiura Shozo H. , Lovell Richard T.
Published: April 2007

High oleic corn is a genetic variant that contains more protein, lipid, and oleic acid and less linoleic acid than regular corn. A study was conducted to compare weight gain and feed conversion of year‐1 and year‐3 channel catfish Ietalurus punctatus, and processing yield, body composition and frozen storage stability of year‐3 channel catfish fed high oleic corn and number 2 yellow (regular) corn in extruded production diets. A commercial‐type diet formulated to contain 30% protein and made with regular corn served as a control. A second diet contained high oleic corn in place of regular corn on an equal (air‐dry) weight basis. A third diet contained high oleic corn in substitution for regular corn and part of the soybean meal to limit protein content to 28%, which was equal to that of the control diet. The experimental diets were fed to year‐1 channel catfish (average initial weight 5.1 g) in aquaria for 10 wk and to year‐3 channel catfish (average initial weight 1.07 kg) in 0.04–ha ponds for 14 wk. Substitution of high oleic corn for regular corn on an equal (air‐dry) weight basis provided significant gain (P < 0.01) of year‐1 channel catfish but not of year‐3 fish. Use of high oleic corn diets designed to be equal in protein content did not affect weight gain of either group of fish. Replacement of regular corn with high oleic corn caused a significant (P < 0.01) reduction in linoleic acid but no significant (P > 0.20) increase in oleic acid in the flesh of fish. Proximate body composition, dressing yield, fillet yield, visceral fat, and liver weight were not significantly different among treatments. Sensory scores of fillets frozen for 3 and 6 mo were not significantly different among treatments. Peroxide value, thiobarbituric acid number and free fatty acids increased with frozen storage time but were not different among treatments.
Dietary Phosphorus Requirement of Juvenile Striped Bass Morone saxatilis1
Authors: Dougall David S. , Woods L. Curry , Douglass Larry W. , Soares Joseph H.
Published: April 2007

Three experiments were performed in single‐pass, flow‐through systems to determine the dietary phosphorus requirement of striped bass Morone saxatilis. In Experiment 1, three semi‐purified diets were formulated to contain 0.20, 0.40, or 0.60% total phosphorus (entirely from animal protein) and were fed to striped bass having an average initial weight of 321 g. After 14 wk of feeding, significant differences in bone and scale mineralization were found among treatment groups. At a level of 0.40% dietary phosphorus there was a significant improvement of serum calcium (Ca) and tissue mineralization. In Experiment 2, five diets were formulated with graded levels of monopotassium phosphate to yield total phosphorus levels of 0.15 (no P supplementation), 0.35, 0.55, 0.75, and 0.95% and fed to juvenile striped bass initially weighing an average of 7.9 g. After 6 wk, significant improvement in scale and vertebral mineralization occurred when fish were fed diets containing at least 0.55% phosphorus. Improvements were observed in growth, serum phosphorus, incidence of scoliosis, survival, and feed efficiency when the diet contained at least 0.35% P. In Experiment 3, the dietary phosphorus levels fed were 0.30, 0.38, 0.46, 0.54, and 0.62% total phosphorus using graded levels of monopotassium phosphate. Diets were fed to striped bass fingerlings initially weighing an average of 48 g. After 10 wk, significant improvement in scale, vertebral, and dorsal fin mineralization was observed when dietary phosphorus was at least 0.46%. A summary of the broken‐line regression analyses of the data from these experiments indicated that the average total dietary phosphorus level required for optimal growth and mineralization of striped bass was 0.58%.
Nutritional Value of Preserved Microalgae for Subadult Mytilus galloprovincialis
Authors: Esquivel Beatriz Cordero , Voltolina Domenico
Published: April 2007

Abstract.— Subadult (4–5 cm) Mytilus galloprovincialis were fed for 31 d with equal daily rations, equivalent to 6% of their body weight on a dry weight basis, of Chaetoceros sp. and Phaeodactylum tricornutum fresh, or preserved by air‐drying, freeze‐drying, and by freezing. At the end, increases in size, in dry weight, and in condition index with preserved diets were significantly lower than those of the mussels fed with live algae. In general, the frozen diets were better than the air‐ and freeze‐dried ones. Increases with live Chaetoceros sp. were greater than with live P. tricornutum; however, with preserved diets the latter was better than Chaetoceros sp.
Assessment of Demand Feeder Spacing on Hatchery Performance, Fin Condition, and Size Variation of Rainbow Trout Oncorhynchus mykiss
Authors: Wagner Eric J. , Routledge M. Douglas , Intelmann Steven S.
Published: April 2007

Abstract.— Fingerling rainbow trout, Oncorhynchus mykiss, were fed for 133 d by one of three feeding methods: one demand feeder per 5.5 m of raceway, 2 demand feeders per 5.5 m of raceway, and hand‐fed controls. Mean weight, total length, mortality, and feed conversion were not influenced by the method of feeding. Size variation did not differ among treatment groups, as assessed by comparing the coefficient of variation of total length. Necropsy‐based health and condition profiles were conducted three times during the rearing period, and results indicated that fish were generally normal and healthy in all treatments. Several parameters differed significantly over time, but no trends were observed except for the fin index and hematocrit. Over time, hematocrit decreased from 48.6 to 45.0%, and the fin index increased from 0.80 to 1.57. Fin index values did not differ among the feeding methods. Fin condition assessed by measuring relative fin length was better in the single feeder treatment than controls for caudal and ventral fins in the last sample. However, since fish from the two‐feeder treatment did not differ from controls, demand feeding per se did not improve fin condition relative to fish that were fed by hand, four to six times per day. The lack of significant improvements in growth or health with the addition of another demand feeder indicated that using more than one feeder per 5.5 m of raceway length is unnecessary for culture of juvenile rainbow trout.
Supplemental Phosphorus in Practical Channel Catfish Diets1
Authors: Robinson Edwin H. , Jackson L. Scott , Li Meng H.
Published: April 2007

Three experiments were conducted to evaluate the need for supplemental phosphorus in the diet of channel catfish Ictalurus punctatus as well as to compare dicalcium phosphate and defluorinated phosphate as sources of supplemental phosphorus. Fingerling channel catfish were stocked into 0.04‐ha earthen ponds at a rate of 1,000 fish/pond (24,700ha). The fish were fed a feed typical of commercial catfish feeds containing 28% protein and 2.8 kcal digestible energy/g once daily to satiation during the growing season (April to October). Fish in experiment 2 were overwintered and fed at a rate of 1% body weight twice weekly when the water temperature exceeded 13 C. The basal diet used in experiments 1 and 2, which contained no supplemental phosphorus, had estimated available phosphorus concentrations of 0.26 and 0.20%, respectively. Dicalcium phosphate was added to provide available phosphorus concentrations of 0.34 and 0.41% for experiment 1, and 0.27 and 0.35% for experiment 2. Diets used in experiment 3 to compare dicalcium and defluorinated phosphates contained 0.40% available phosphorus. Data from experiments 1 and 2 indicated that a concentration of dietary phosphorus of about 0.27% was adequate for maximum weight gain and efficient conversion of feed by channel catfish. However, a concentration of about 0.35% available phosphorus was required for maximum bone mineralization in experiment 2. There were no differences in growth or bone mineralization between fish fed dicalcium or defluorinated phosphate. We conclude that the small increase in bone phosphorus (about 4%) is biologically insignificant, and suggest that 0.3% available phosphorus be adequate for channel catfish raised in earthen ponds. Also, either dicalcium or defluorinated phosphate can be used as a source of supplemental phosphorus in channel catfish diets. However, defluorinated phosphate may be desirable because of its low solubility in water.
Natural Spawning of Captive Bigeye Scad Selar crumenophthalmus in Hawaii
Authors: Iwai Thomas Y. , Tamaru Clyde S. , Yasukochi Leslee , Alexander Shelley , Yoshimura Rona , Mitsuyasu Mark
Published: April 2007

Abstract.— Juvenile bigeye scad Selar crumenophthalmus were caught from the wild by hook and line and reared over 3 yr to establish a spawning broodstock of this species. The size at first maturity for captive males and females was 19‐cm and 25‐cm fork length (FL). Natural spawning of captive individuals occurred during the first year in captivity. The broodstock were observed to spawn repeatedly throughout their second and third years in culture. This species is a multiple spawner producing approximately 96 × 103 to 121 × 103 eggs/spawning group, 5 to 10 times per year. Stocking densities of 1–8 individuals/m3 were found to be suitable for natural spawning to occur. Collectively, the results indicate that this species exhibits notable potential for artificial propagation.
Growth Curves for Macrobrachium rosenbergii in Semi‐Intensive Culture in Brazil
Authors: Sampaio Célia M. S. , Valenti Wagner C.
Published: April 2007

Abstract.— Four 0.02‐ha earthen ponds at the UNESP Aquaculture Center, Jaboticabal, São Paulo, Brazil, were stocked with newly metamorphosed Macrobrachium rosenbergii post‐larvae at 1.5 animals/m2. After 8 mo, prawn density at harvest ranged from 0.3/m2 to 0.8/m2. Growth curves were determined for each population using von Bertalanffy growth functions. Asymptotic maximum length and asymptotic maximum weight increased as final population size decreased indicating that a strong density effect on prawn growth occurs in semi‐intensive culture, even when populational density varies within a small range of less than 1 animal/m2.
A Mammalian Growth Hormone‐Releasing Hormone Increases Serum Growth Hormone Levels and Somatic Growth at Suboptimal Temperatures in Tilapia
Authors: Kelly Anita M. , Kohler Christopher C. , Grau E. Gordon
Published: April 2007

The effects of a mammalian growth hormone‐releasing hormone (GHRH), PrebGRF(1–78)OH (bGHRH), on growth and serum growth hormone (GH) levels were investigated in tilapias Oreochromis mossambicus andO. niloticus × O. aureus. Fish were injected intramuscularly or implanted intramuscularly (Silastic or cholesterol implants) with distilled water, 0.1 μg/kg bGHRH, 1.0 μg/kg bGHRH, 10.0 μg/kg bGHRH, or 100.0 μg/kg bGHRH and compared to untreated controls, fish implanted with 60 mg/kg 17α‐methyltestosterone (MT), or a combination of bGHRH concentrations plus either MT, 0.01 μg/kg of a thyroid hormone (T3), or 0.01 μg/kg of a glucocorticoid (DEX). The bGHRH increased serum GH levels in tilapia maintained at suboptimal temperatures (18 C). Serum GH levels were highest (5.3–0.45 ng/mL) for fish injected with 10.0 μg/kg bGHRH. Fish implanted with a Silastic implant containing 10.0 μg/kg bGHRH had significantly higher (4.35–0.35 ng/mL) serum GH levels than those with an equivalent dosage in a cholesterol implant. The addition of MT, thyroid hormones, and glucocorticoids did not increase serum GH levels above those obtained for fish receiving bGHRH alone. Tilapia reared at suboptimal temperatures and implanted with 10.0 μg/kg and 100.0 μg/kg bGHRH had significantly greater increases in weight and length than control fish. Fish implanted with bGHRH, MT or bGHRH plus MT had significantly higher moisture and protein content, while fat and ash contents were significantly lower than controls or sham‐implanted fish. Fish implanted with bGHRH or bGHRH plus MT had significantly higher gonadosomatic indices than fish implanted with MT alone, shams or non‐treated controls. This study demonstrates that a mammalian GHRH stimulates release of GH, promotes somatic and gonadal growth and may affect reproductive performance in tilapia.
Effects of Temperature and Salinity upon Larval Growth, Survival and Development in Hatchery Reared Southern Atlantic Surfclams Spisula solidissima similis
Authors: Hurley Dorset H. , Walker Randal L.
Published: April 2007

Abstract.– Parameters associated with optimum larval‐rearing conditions are important in developing the culturing protocol of potential aquacultural species, and have yet to be addressed in terms of water temperature and salinity for Spisula solidissima similis, the southern Atlantic surfclam. Hatchery spawned S. s. similis larvae were reared to late pediveliger stage in five simultaneously conducted water temperature and salinity treatments. This larval growth and survival experimentation consisted of three salinity treatments (15, 25 and 30 ppt) in conjunction with a water temperature of 20 C, and two water temperature treatments (15 and 25 C) in conjunction with a salinity of 25 ppt. In the 20 C temperature treatment, significantly higher larval survival and greater growth occurred (both, P < 0.0001) as compared to the 15 C and 25 C treatments by day 22. Complete larval mortality occurred in the 20 C, 15 ppt salinity treatment by day 4. No significant differences in larval survival occurred between the 25 ppt, 20 C and 30 ppt, 20 C treatments by day 22 (P = 0.714). However, significantly greater larval growth occurred in the 25 ppt, 20 C compared to the 30 ppt, 20 C treatment (P = 0.009). The optimum rearing temperature and salinity for hatchery spawned S s. similis larvae to late pediveliger stage are 20 C and 25 ppt, respectively, within the temperatures and salinities tested.
Red Drum Sciaenops ocellatus Field Trials: Economic Implications
Authors: Lutz C. Greg , Wolters William R. , Landry Walter J.
Published: April 2007

Abstract.– Although recent changes in coastal fisheries regulations in several Gulf states have renewed interest in the economic potential for culture of red drum S. ocellatus, few decision making tools with up‐to‐date information on production economics are available. From 1988 to 1995, estimates of investment costs, equipment specifications and typical input utilization in commercial‐scale production were developed from field trials involving complete or partial grow‐out of S. ocellatus. Operating costs and expected yields were subsequently estimated based on “best‐case” data from a 70‐wk production trial in which 5–7 cm fingerlings were stocked on 1 July and grown to marketable size by the following November, thus avoiding a second overwintering period and the associated risks of losses from freezing temperatures. To allow an evaluation of potential returns with earlier or staggered stocking dates, however, growth and mortality rates from the 70‐wk trial were used in a computer‐based simulation to estimate yields and costs associated with a hypothetical growout period beginning 1 April, deemed the earliest suitable date to avoid fingerling mortality resulting from abrupt or extreme cold temperatures. The April stocking simulation projected a preferred market size of 1.4 kg prior to a second overwintering period, with yield increasing from 3,454 kg/ha to 4,203 kg/ha and a reduction in breakeven costs from $5.97/kg to $5.53/kg. Partial budget analysis, based on a current average market price of $5.72/ kg, suggested April 1 stocking could result in a positive net change of $1,679 per ha over July 1 stocking.
Efficiency of Water Use of an Integrated Fish/Vegetable Co‐Culture System
Authors: McMurtry M. R. , Sanders D. C. , Cure J. D. , Hodson R. G. , Haning B. C. , Amand E. C. St.
Published: April 2007

Abstract.– Fish and vegetable production were linked in a recirculating water system designed to achieve a high degree of efficiency of water use for food production in addition to functional and technological simplicity. Hybrid tilapia Oreochromis mossambicus×O. niloticus L. were grown in tanks associated with biofilters (sand beds) in which tomatoes Lycopersicon esculentum were grown. The effect of four biofilter volume (BFV)/fish rearing tank volume ratios (0.67/1, 1.00/1, 1.5011, 2.25/1) on water use efficiency was evaluated.‘Laura’(first experiment) or‘Kewalo’tomatoes were grown 4/m2 in biofilters of four different sizes and surface‐irrigated 8 times daily with water from the associated fish tanks. Daily water consumption increased with BFV/tank ratios and with time. Fish production rates increased with biofilter volume in the first experiment, but were not significantly different in the second experiment. Total tomato fruit yield per plot increased from 13.7 to 31.7 kg (Experiment 1) and from 19.9 to 33.1 kg (Experiment 2) with increasing BFV/tank ratio. For fish plus fruit, total energy production increased from 4,950 to 8,963 kcal/ plot and from 4,804 to 7,424 kcal/plot in Experiments 1 and 2, respectively, and protein production increased from 536 to 794 and from 352 to 483 g/plot in Experiments 1 and 2, respectively, with increasing BFV/ tank ratio. Trends in water use efficiency for production of food energy (kcal/L.) and of protein (g/L) in tomatoes and fish were complex. Water use efficiency
Evaluation of Three Soybean Products in Diets Fed to Juvenile Hybrid Striped Bass Morone saxatilis×M. chrysops
Authors: Brown P. B. , Twibell R. , Jonker Y. , Wilson K. A.
Published: April 2007

Juvenile hybrid striped bass Morone saxatilis×M. chrysops were fed practical diets containing graded levels of either solvent‐extracted soybean meal, roasted soybeans, or raw, unprocessed soybeans. Two separate 10‐wk studies were conducted; within each study, there were two separate evaluations of soy products. In the first study, weight gain and feed efficiency of fish fed 45% or higher levels of soybean meal were significantly lower than fish fed the positive control diet, while weight gain and feed efficiency of fish fed 30% soybean meal were not significantly different than fish fed the control diet. Fish fed the lowest level of unprocessed soybean (20%) exhibited significantly depressed weight gain and feed efficiency compared to fish fed the control diet. In the second study, weight gain and feed efficiency of fish fed 40% roasted soybeans were significantly lower than fish fed the control diet, but weight gain and feed efficiency of fish fed 20% roasted soybeans were not significantly lower than fish fed the control diet. In both studies, whole body proximate composition values were significantly different among treatments. Whole‐body lipid concentrations were significantly higher in fish fed certain levels of soy products, but only at levels above those eliciting depressions in weight gain and feed efficiency. A further evaluation of solvent‐extracted soybean meal was conducted with incorporation levels of 20–40% of the dry diet in gradations of 5% with a nutritionally complete mineral premix. Weight gain and feed efficiency of fish fed any level of soybean meal in that study were not significantly different from fish fed a positive control diet. Whole body proximate components were not significantly different between treatments. Unprocessed soybeans apparently have little potential as an ingredient in diets fed to juvenile hybrid striped bass; roasting, or heat treatment, improves their use. Solvent extracted soybean has the potential of supplying the majority of crude protein in diets fed to juvenile hybrid striped bass. Incorporation of complete mineral premixes seems beneficial with higher levels of solvent‐extracted soybean meal.
Low Protein Diets for Channel Catfish Ictalurus punctatus Raised in Earthen Ponds at High Density1
Authors: Robinson Edwin H. , Li Meng H.
Published: April 2007

This study was conducted to evaluate the use of low protein diets for channel catfish Ictalurus punctatus raised in earthen ponds at high density. Fingerling channel catfish were stocked into 0.04‐ha earthen ponds at a rate 24,700 fish/ha and fed experimental diets daily to satiation from April to October 1995. The five diets contained either 32, 28, 24, 20, or 16% crude protein with digestible energy to protein (DE:P) ratios ranging from 8.9 to 16.2 kcal/ g protein. Weight gain was not different among channel catfish fed diets containing 32, 28, or 24% crude protein. Fish fed diets containing 20% or 16% crude protein gained less weight than fish fed the diets containing 28% or 24% crude protein, but not statistically less than the fish fed the 32% crude protein diet. Feed consumption data followed similar trends as weight gain data. Feed conversion ratio increased linearly as dietary protein decreased, but was not significantly different (multiple range test) for fish fed diets containing either 32% or 28% crude protein. There were no differences in survival and hematocrit of fish fed the different diets. No differences (multiple range test) were observed in dressout percentages for fish fed the various diets, but dressout percentage tended to decrease linearly as dietary protein decreased. Visceral fat and fillet fat increased and fillet protein and moisture decreased linearly as dietary protein decreased. Results from this study indicated that dietary protein concentrations as low as 24% are adequate for maximum weight gain of pond‐raised channel catfish fed daily to satiation. Fish fed dietary protein levels below 24% grew relatively well, particularly considering that dietary protein was reduced 40–50% below that typically used in commercial channel catfish feeds. However, dietary protein levels below 24% may increase fattiness to an unacceptable level presumably because of the high digestible energy to protein ratio.
Response of Atlantic Croaker Fingerlings to Practical Diet Formulations with Varying Protein and Energy Contents
Authors: Davis D. Allen , Arnold Connie R.
Published: April 2007

Atlantic croaker Micropogonias undulatus is a demersal marine species that is heavily utilized as both a bait and food fish, and which may have commercial culture potential as a bait species. This research sought to initiate the development of practical diet formulations for juvenile grow out and to evaluate the response of this species to controlled culture conditions. Eight practical diets were formulated to evaluate the effects of. 1) increasing lipid levels in a 45% protein diet; 2) dietary protein levels of 45, 40, 35 and 30%; and 3) progressive reduction in dietary energy content of diets with 30% protein. Each diet was offered to four replicate groups of fish having a mean initial weight of 3.8 g over a 7–wk growth trial. At the conclusion of the trial, final mean weights ranged from 17.0 g (410% weight gain) to 8.1 g (210% weight gain) with 100% survival for all dietary treatments. Weight gain and feed efficiency increased with protein content of the diet, with fish fed the 45% protein diet performing the best. Weight gain of fish maintained on the 45% protein diet decreased, but not significantly, as the lipid content of the diet was increased from 8 to 12 or 16%. Feed efficiencies for fish maintained on the diet containing 8% lipid were significantly higher than that of fish maintained on the diet containing 16% lipid. In low protein diets, the replacement of wheat starch with indigestible fiber did not significantly influence growth or feed utilization, indicating that high levels of digestible carbohydrate were not well utilized as an energy source by the fish. The observed results would indicate that growth is optimized on a high protein diet with moderate lipid levels.