bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preliminary Observations on the Marketability of Saltwater‐Cultured Florida Red Tilapia in Puerto Rico
Authors: Head William D. , Zerbi Alfonso , Watanabe Wade O. 
Published: April 2007

AbstractA preliminary assessment of the marketability of saltwatercultured Florida red tilapia was conducted at a farm outlet store and at nine restaurants in Puerto Rico. Florida red tilapia were grown in six 0.2‐ha ponds at 22.7 ± 1.2 (mean ± SE) ppt salinity by a commercial aquaculture enterprise in Dorado, northeastern Puerto Rico. Customers purchased 4,683kg of dressed‐out fish (gilled, gutted and scaled) at $7.70/kg and 826kg of whole fish at $6.60/kg from a retail outlet store located at the aquaculture farm, and nine restaurants purchased 1,071kg of dressed‐out fish at wholesale prices ranging from $4.96 to $5.18/kg. Farm outlet customers and restaurants preferred dressed‐out fish between 454–567g and 567–580g, respectively. Prices paid per serving by restaurant customers for red tilapia ($7.00–$25.00) were similar to that paid for silk snapper Lutjanus vivanus, a popular marine food fish in Puerto Rico. Market surveys of customers at these outlets showed that 75–81% of the respondents were new consumers of red tilapia and that they rated red tilapia highly in taste, texture, freshness, and presentation and equal to or better than silk snapper. There was no effect (P > 0.05) of age group or economic level on consumer responses. Survey participants stressed the need for product promotion, including a more markehriented name that emphasized the red color and that it was farm‐raised in saltwater, to distinguish it from darkcolored, wild‐caught freshwater tilapia. Local saltwater production of Florida red tilapia could help supply the market demand for fresh, marine fish in Puerto Rico if producers can meet the demand for quality, availability and price.
Effect of Total Water Hardness and Chloride on Survival, Growth, and Feed Conversion of Juvenile Red Drum Sciaenops ocellatus
Authors: Pursley Michael G. , Wolters William R. 
Published: April 2007

AbstractJuvenile red drum Sciaenops ocellatus were tank‐reared in two, separate 30‐d trials to assess effects of total water hardness and chloride concentratlon on growth, survival, and feed conversion. Two levels of total hardness and chloride were used in 2 × 2 factorial designs to obtain total hardness and chloride levels in trial one of 100 and 200mg/L CaCO3 and 125 and 250mg/L Cl−, and hardness and chloride levels of 100 and 400mg/L CaCO3 and 150 and 500mg/L Cl− in trial two. In trial one, average daily growth and feed conversion were significantly (P≤ 0.05) improved at 100mg/L hardness levels compared to 200mg/L at both chloride levels. Average daily growth was 0.11 ± 0.02g/d at 100mg/L hardness and 125mg/L Cl− compared to 0.06 ± 0.01g/d at 200 mg/L hardness and 125mg/L chlorides. No significant (P≥ 0.05) difference in survival could be attributed to levels of total hardness or chloride. In trial two, 500 mg/L Cl− treatments produced significantly (P≤ 0.01) better growth, survival and feed conversion than 150mg/L Cl− at either level of total hardness (100 and 400mg/L). Survival at 150mg/L chloride and 100mg/L hardness was 48.8 ± 18.7%, while at 500mg/L chloride and 400mg/L hardness survival increased to 96.6 ± 2.1%. Growth also increased from 0.14 ± 0.03 to 0.27 ± 0.01g/d and feed conversion improved from 5.77 ± 1.56 to 1.87 ± 0.06 at the same levels. No interactions between levels of hardness or chlorides were shown to affect red drum growth, survival, or feed conversion in either trial.
Egg Quality Determinants in Finfish The Role of Overripening with Special Reference to the Timing of Stripping in the Atlantic Halibut Hippoglossus hippoglossus
Authors: Bromage Niall , Bruce Mike , Basavaraja Ngappa , Rana Krishen , Shields Robin , Young Carl , Dye John , Smith Peter , Gillespie Malcolm , Gamble John 
Published: April 2007

AbstractEgg quality, those characteristics of the egg that determine its capacity to survive, is a significant problem for many species of fish currently being farmed. Little is known about the determinants of egg quality and there is little agreement regarding reliable methods for its assessment. To be of practical benefit, assessments should be simple to perform and should be carried out as early in development as is possible. Fertilization rates are often used as measures of quality. For the Atlantic halibut Hippoglossus hippoglossus, fertilization rate and assessments of cell symmetry at early cleavage stages provide reasonable indicators of quality. Regardless of assessment method, it is strongly recommended that performance data from all batches of each broodfish be examined when surveying the overall quality of a stock. The misleading effects of pooling such information are demonstrated for a rainbow trout Oncorhynchus mykiss broodstock. Although a large number of factors have been implicated as possible determinants of egg quality, only 1) bacterial colonization of the eggs, 2) nutritional status of the broodfish and, 3) overripening, the process of aging that occurs when eggs are retained within the broodfish after ovulation, have been clearly shown to affect egg quality.The effect of overripening on fish egg quality is discussed in detail. Species‐specific differences in the time scale of overripening are pointed out and related to spawning strategy and water temperature. Rainbow trout eggs and those of other salmonids should be fertilized within approximately one week of ovulation. Overripening proceeds much more rapidly in warm water species, e.g., tilapia eggs must be fertilized within an hour or so of ovulation. Egg viability also decreases rapidly for batch spawning species. Fertilization data are presented for Atlantic halibut demonstrating that egg quality decreases 4–6 h after ovulation. The rate of overripening was comparable for eggs held in vitro in ovarian fluid to those retained within the ovarian lumen. These halibut data, combined with information from other marine and freshwater fish, indicate that overripening is a significant determinant of egg quality for many if not all fish.
Egg Quality in Wild and Broodstock Cod Gadus morhua L.
Authors: Kjørsvik Elin 
Published: April 2007

AbstractProblems concerning egg viability or egg quality have received increasing attention, in relation to cultivation as well as to the assessment of reproduction of wild fishes. One important aspect of this paper is to discuss the use of cell morphological characteristics as indicators of egg quality in cod. Early cellular malformation rates in egg batches show a positive correlation with their later egg and larval survival, and can be used as a rough prediction of normal development and mortality rates.The natural mortality rate offish eggs is not well understood, and observed egg viability of captive cod is are discussed in relation to egg viability in the wild. Results from recent work indicated that approximately 10% of naturally spawned cod eggs from both wild fish (planktonic samples) and from a broodstock had abnormal cleavages at the 2–128 cell stage. Eggs with observed early abnormal cell‐cleavage showed very poor survival and hatching rates. For broodstock cod, egg viability was highest during the peak of the spawning season.The North Atlantic cod may provide a good model species for studies of egg viability variations in wild and captive individuals, as its reproductive biology is well studied. It is now documented that the egg production in cod is dependent on fish age, nutritional status, batch number, and stress factors.
Effects of Fasting on Fatty Acid Composition of Muscle, Liver, and Abdominal Fat in Channel Catfish Ictalurus punctatus
Authors: Webster Carl D. , Tidwell James H. , Goodgame Laura S. , Yancey Daniel H. 
Published: April 2007

AbstractChannel catfish Zctalurus punetatus were fasted for 20, 40, 60, and 80 d. Proximate and fatty acid composition of liver, abdominal fat, muscle, and viscera were determined. Percentage moisture, protein, and lipid of viscera showed little change during the period of fasting. Percentage protein in muscle decreased (P < 0.05) after 20 d of fasting from time 0 (control), while percentage lipid increased (P < 0.05). Fish fasted for 0, 40, 60, and 80 d were not different (P > 0.05). In the liver, percentage lipid was higher in fish that were not fasted (0 d) than in fish fasted 20, 40, 60, and 80 d (P < 0.05). while percentage moisture was lower in control fish compared to all other treatments (P < 0.05). Fatty acid composition of muscle and liver indicated that docosahexaenoic acid (DHA), 22:6(n‐3), was conserved in these tissues during fasting, while oleic acid, 18:1(n‐9), concentration decreased during fasting. Fatty acid composition of abdominal fat indicated that a high percentage (>50%) of the total lipid was composed of oleic acid and there was little change in levels of individual fatty acids in abdominal fat during 80 d of fasting.
Digestive Characteristics of the Sea‐Urchin Lytechinus variegatus (Lamarck) (Echinodermata: Echinoidea) Fed Prepared Feeds
Authors: Klinger Thomas S. , Lawrence John M. , Lawrence Addison L. 
Published: April 2007

Abstract Lytechinus variegatus were fed two prepared feeds identical in composition except one contained only soybean protein and the other contained equal concentrations of fish and soybean protein. Feeding rate, defecation rate, passage time through the gut, apparent dry matter digestibility of protein and carbohydrate, and the production of gut tissue did not differ significantly (P > 0.05) with feed type. Individuals about 50 mm in diameter and 60% wet body‐weight consumed about 3‐g wet weight of feed per day. Feeding rate decreased during the experiment, but defecation rate did not. The throughput rate was two days with considerable mixing of feed in the gut. Fecal production ceased two days after cessation of feeding. Only trace amounts of feed remained in the gut three days after feed was not available. The apparent dry matter digestibility was 62% for soluble protein and 35% for soluble carbohydrate for both feeds. The apparent dry matter digestibility of ash was 19% for the feed with soybean meal alone, and 11% for soybean and fish meal. The apparent dry matter digestibility calculated by the use of chromic oxide is greater than that calculated by the use of ash.
Supplemental Feeding of Tilapia in Fertilized Ponds
Authors: Diana James S. , Lin C. Kwei , Jaiyen Kitjar 
Published: April 2007

AbstractThe addition of feed to fertilized fish ponds was evaluated by adding feed alone, feed plus fertilizer, or fertilizer alone to nine ponds stocked with Nile tilapia Oreochromis niloticus. Two experiments were conducted. The first had 500 fish per 250 m2 pond in 3 treatments: ad‐libitum feeding; fertilizer only; or fertilizer and ad‐libitum feeding. The second experiment had 5 treatments with 750 fish per pond ad‐libitum feed only; fertilizer only; or 0.25, 0.50, and 0.75 satiation ration plus fertilizer. Ponds in Thailand were maintained for 155–162 d, during which chemical and physical properties were monitored. In experiment 1 tilapia growth was highest in feed only ponds, and lowest in fertilizer only ponds. Net yield did not differ significantly among treatments, due to variation in survival. In experiment 2, tilapia growth was lowest in fertilizer only ponds, intermediate in 0.25 ration ponds, and highest in 0.50, 0.75, and ad‐libitum ponds. The latter treatments were not significantly different. Multiple regressions for each experiment indicated only 47–87% of the variance in growth was explained by feed and fertilizer input, while 52–89% of the variance in yield was explained by those factors. For both experiments combined, 90.3% of the variance in growth was explained by feed input, fertilizer input, alkalinity, and total inorganic nitrogen concentration. For yield, R2 was 0.888 and the regression included feed input, pH, and number of low dissolved oxygen events. Experiment 1 appeared to approach carrying capacity near the end, while no reduction in growth occurred in experiment 2 at higher fish density and biomass. Reductions in growth in experiment 1 were not correlated with declining water quality late in the grow out. Combinations of feed and fertilizer were most efficient in growing tilapia to large size (500 g) compared to complete feeding or fertilizing alone.
Pressure Induced Triploidy in Hybrid Lepomis
Authors: Wills Paul S. , Paret John M. , Sheehan Robert J. 
Published: April 2007

AbstractWorldwide expansion of aquaculture will require identification of species more adapted to localized conditions and less likely to affect genetic diversity of natural populations in the event of escape. Hybrids of Lepomis sunfish have the potential as an alternative for aquaculture in regions of North America where the growing season is unsuitable for production of traditional coldwater and warm‐water species. Triploidy was induced in hybrids of green sunfish Lepomis cyanellus males and bluegill L. macrochirus females using hydrostatic pressure shocks. A total of 27 combinations of pressure (41,369, 48,264, and 55,158 kPa), duration (2, 3, 4 min), and post‐fertilization time of shock initiation (2, 3, 4 min) were tested to identify those which were most efficient for inducing triploidy. Several of the shock regimes produced 100% triploid hybrid sunfish with at least 90% survival relative to unshocked controls. The two shock treatments deemed best overall were: 1) 48,264 kPa for 4 min begun 2 min after fertilization; and 2) 41,369 kPa for 2 min begun 3 min after fertilization.
Effects of Population Density and Feeding Rate on Growth and Feed Consumption of Red Swamp Crawfish Procambarns clarkii
Authors: McClain W. Ray 
Published: April 2007

AbstractWire‐mesh enclosures were used in production ponds to conduct growth trials in which population density and feeding rate were evaluated in a 2 × 2 factorial arrangement for their effects on crawfish growth. Juvenile Procambarus clarkii of uniform size (0.5 g) were stocked at 2 or 20 animals/m2 in experiment 1 and weighed biweekly for 12 wk. Rice forage served as the detrital base, and supplemental feed (25% crude protein) was provided at either a low (26–52 kg/ha per week) or high (104–418 kg/ha per week) rate. In experiment 2, mixed sizes of crawfish were stocked at 10/m2 or 20/m2 and fed the formulated feed at either 52 or 312 kg/ha per week. Feed consumption was estimated for each treatment combination. Only population density significantly affected crawfish growth. Mean weight gain and final weights were inversely proportional to density but only when total crawfish biomass exceeded 1,235 kg/ha. Growth was not significantly influenced by feeding rate, but the high feeding rate resulted in a significantly greater ratio of hepatopancreas weight to body weight and tended to decrease hepatopancreas moisture levels, indicating improved condition. Population density, feeding rate, and their interaction had significant effects on estimated feed consumption. From the simple linear regression of mean feed consumption on crawfish standing crop, it was estimated that crawfish consume about 0.1 kg of dry feed per ha per week per kg of crawfish biomass on a 5 d per week feeding schedule at mean water temperatures, ranging from 14 to 30 C.
Growth of Crawfish Procambarus clarkii as a Function of Density and Food Resources
Authors: McClain W. Ray 
Published: April 2007

AbstractThis study utilized enclosures (cylindrical, 5‐mm wire mesh, O.5 m2 bottom surface area) placed over rice‐forage substrates in experimental crawfish ponds to contain crawfish under typical pond culture conditions. Juvenile Procambarus clarkii were stocked at six densities (2, 4, 6, 10, 14, and 18 crawfish/m2) for 12‐wk growth trials in October and again in February. Crawfish relied solely on the detrital food system for their nutritional needs. Supplemental feed was supplied to crawfish in additional enclosures at two of the test densities (2 and 10 crawfish/m2). The commercially formulated feed (25% crude protein) was fed (2.02 g dry feed/m2) 3 d/wk (Monday, Wednesday, Friday). All treatments were replicated with six enclosures. Crawfish growth was inversely correlated to culture density. Mean final weights for crawfish feeding from the detrital‐system only were 15.3, 13.8, 11.2, 7.9, 7.2, and 5.8 g for crawfish densities of 2, 4, 6, 8, 10, 14, and 18/m2, respectively. Mean final weights for crawfish receiving supplemental feed were 20.7 and 12.4 g for densities of 2 and 10 crawfish/m2. When compared with density as a factor influencing growth, feed influenced growth less than density abatement. Supplemental feeding improved crawfish growth in detrital systems an average of 46%, while decreasing initial density improved growth an average of 80.5%.
Observations on Monosex Culture of Redclaw Crayfish Cherax quadricarinatus von Martens (Decapoda: Parastacidae) in Earthen Ponds
Authors: Curtis Millin C. , Jones Clive M. 
Published: April 2007

AbstractManual sexing of redclaw crayfish Cherar quadricurinatus was undertaken to evaluate the feasibility of monosex culture and to establish growth and yield characteristics of single sex populations. Although the all‐male population exhibited greater mean weight after 10 mo of growout, all‐female and mixed sex populations achieved greater total yields due to significant juvenile recruitment. Commercial cultivation of all‐male populations would be advantageous as in‐pond reproduction is greatly abated, growth is superior and marketable yield is higher. Apparent sexual lability of juveniles combined with the laborious nature of manual sexing may render manual sexing unsuitable for commercial applications.
Mathematical Model of a Foam Fractionator Used in Aquaculture
Authors: Timmons M. B. , Chen S. , Weeks N. C. 
Published: April 2007

AbstractWater recirculating systems are becoming more prevalent as wild fish supplies and fresh water sources become increasingly scarce. As water recirculating rates increase, the accumulation of fine and dissolved solids can degrade water quality and fish productivity. Foam fractionators have been used with some success to remove these solids, although an understanding of how to best operate such units is currently lacking. The foam enrichment process occurs as bubbles travel from the bottom of a fractionator column to the top of the water column. Factors affecting bubble enrichment include several operating or design parameters under operator control or influence, e.g, water pH, gas bubble size, airflow rates, and fractionator geometry. Predictive relationships were developed to describe these effects and are considered generally applicable to predict the foam enrichment process. Predicting the actual operation of a specific foam fractionator requires additional mathematical expressions to model the foam collection process and removal from the top of the water column. Here, the geometric characteristics and type of foam removal device or geometry of placement become important. Performance data in the literature was used in coajunction with a mathematical model that predicted foam enrichment to model the foam collection process for a typical foam fractionator design. This overall model can be used for foam fractionators that employ glass bonded air diffusers with an inverted funnel at the top of the fractionator column to concentrate and remove the foam being produced. An example problem is given to demonstrate the utility of the mathematical models. Since foam fractionators are typified by erratic performance, the mathematid models presented must be used with some caution and only viewed as providing estimates of average fractionator performance.
Induced Spawning of Wild American Shad Alosa sapidissima Using Sustained Administration of Gonadotropin‐Releasing Hormone Analog (GnRHa)
Authors: Mylonas Costadinos C. , Zohar Yonathan , Richardson Brian M. , Minkkinen Steven P. 
Published: April 2007

AbstractAmerican shad Alosa supidissima broodstock were collected from the Susquehanna River during their spawning migration. Mean volume of expressible milt (± standard deviation) was 2.5 (±1.7) mL/kg body weight; mean spermatozoid count was 66.2 ± 109 (±163 ± 109) spermntozoa/mL; and duration of 50% motility was 36.5 (±10.3) see. Ovarian biopsies indicated the presence of oocytes of various sizes (200–2,000 μm in diameter) and stages of development. Fish were implanted with a delivery system loaded with gonadotropin‐releasing hormone analog (GnRHa) and started spawning 2 d after treatment. Fertile eggs were collected daily for the next 9 d, for a total of 50,100 eggs/kg body weight with a mean fertilization success of 62%. Upon cessation of spawning, the ovaries of all females still contained large numbers of oocytes at various stages of development, as at the beginning of the experiment, but with a greater number of atretic oacytes. Our observations show that American shad have an asynchronous ovarian development, and treatment with a GnRHa delivery system is effective in inducing several successive spawns of fertile eggs.
Effect of Time of Feeding on Growth of Channel Catfish1
Authors: Robinson Edwin H. , Jackson L. Scott , Li Meng H. , Kingsbury Susan K. , Tucker Craig S. 
Published: April 2007

AbstractChannel catfish fingerlings were stocked into 16 0.04‐ha ponds at a rate of 24,700 fish/ha on 5 May 1992. Four replicate ponds were used for each of the following treatments: 1) fed once daily at 0830h; 2) fed once daily at 1600h; 3) fed once daily at 2000h; and 4) fed on demand using demand feeders. Fish on the first three treatments were fed to satiation. All fish were harvested 145d after stocking. Results from this study showed that when channel catfish raised in ponds were fed once daily to satiation, time of feeding had no significant impact on water quality, feed consumption, feed conversion, weight gain, or body proximate composition. Fish fed on demand consumed more feed than fish fed once daily to satiation, but difference in weight gain was not significant. These data indicated that feeding time may not be critical for channel catfish production as long as fish are fed when dissolved oxygen is sufficient. Although feeding at night was not detrimental in this study, night feeding is not recommended on large ponds unless sufficient aeration is available to quickly provide oxygen in an emergency—and even then it would be problematic.
Optimization of Dissolved Solids for the Intensive Culture of Juvenile Red Drum Sciaenops ocellatus
Authors: Stahl Christopher J. , Barnes Steven S. , Neill William H. 
Published: April 2007

AbstractSurvival and growth of 0.3–0.9 g red drum Sciaenops ocellatus were measured for fish reared in water‐recirculating culture systems containing one of the following media: 6g/L diluted seawater; 1g/L diluted seawater; 1g/L diluted seawater with either 1 or 5g/L of additional salt. Salt was added as sodium chloride, calcium chloride, or magnesium sulfate. Mean survival over the 42‐d study period was 56.3%. The 5g/L sodium chloride treatment had the highest survival rate (80.0%) and the calcium chloride treatment had the lowest (26.7%). The biomass‐change rate for fish in the 5g/L calcium chloride treatment was significantly lower (P < 0.05) than for fish in the 5g/L sodium chloride, 1g/L sodium chloride, or 5g/L magnesium sulfate treatments. The latter three treatments gave biomass‐change rates that did not differ (P > 0.05) from those obtained in the 1 or 6g/L diluted seawater.