bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incidence of Psorospermium sp. in Several Cultivated Populations of Crayfishes, Procambarus spp. (Decapoda, Cambaridae), in Southern Louisiana
Authors: Henttonen Paula , Lindqvist Ossi V. , Huner Jay V. 
Published: April 2007

AbstractAn organism tentatively classified as Psorospermium haeckeli was found in red swamp crayfish Procambarus clarkii at four culture sites in southwestern (3) and southeastern Louisiana (1) and in white river crayfish Procambarus zonangulus (=P. acutus acutus) at three culture sites in southwestern Louisiana. Incidence was about 70% in P. clarkii and 25% in P. zonangulus. Psorospermium haeckeli was present in all individual populations of P. clarkii sampled, but not in all P. zonangulus populations. Overall abundance was considerably lower than that observed in the European astacid crayfish Astacus astacus. Furthermore, the organism differed in shape, being longer and narrower than the organism found in A. astacus.
Economies of Pond Size for Hybrid Striped Bass Growout1
Authors: Gempesaw Conrado M. , Bacon J. Richard , Wirth Ferdinand F. 
Published: April 2007

AbstractThe objective of this study was to evaluate the relationship of pond size and hybrid striped bass growout profitability as an alternative source of farm income in the Mid‐Atlantic region. A dynamic, whole farm, Montdarlo capital budgeting simulation model (AQUASIM) and stochastic dominance with respect to a function technique were used to analyze the economics of hybrid striped bass growout from phase II to market production stage for eight farms categorized by pond sizes. Three scenarios are assumed to examine the effects of pond‐size dependent changes in feed conversion efficiency and fingerling survival rates on discounted after‐tax net present values and probabilities of economic survival and success. Optimal pond sizes were found to be in the 2.5 acre to 10 acre range.
Fatty Acid Composition of Unfed Cod Larvae Gadus morhua L. and Cod Larvae Feeding on Natural Plankton in Large Enclosures
Authors: van der Meeren Terje , Wilhelmsen Svein , Klungsosyr Jarle , Kvenseth Per Gunnar 
Published: April 2007

AbstractThree different groups of cod larvae Gadus morhua L., feeding on natural plankton in two large enclosures, were analyzed for fatty acid composition through development. Unfed control groups and different size‐fractions of plankton were also analyzed. Consistency in changes of fatty acid composition suggests three developmental periods during early larval development. The periods corresponded with dietary shifts in the larvae, but a metabolic origin for changes in certain fatty acids was also evident. In the first period, relative amounts of n‐9 monounsaturates decreased, while n‐3 polyunsaturates together with certain fatty acids abundant in the small‐sized phytoplankton fraction increased. In the second and third periods, relative amounts of the longer n‐3 PUFA decreased, while fatty acids of calanoid copepod origin occurred in one group. The consistency in changes of larval fatty acid profiles in cod suggests development in both lipid absorption and lipid metabolism during ontogenesis.
Larviculture of the Greasy Grouper Epinephelus tauvina F. and the Brown‐Marbled Grouper E. fuscoguttatus F. in Singapore
Authors: Lim L. C. 
Published: April 2007

AbstractThis paper reports the larviculture of two grouper species, the greasy grouper Epinephelus tauvina and the brown‐marbled grouper E. fuscoguttatus, and examines the technical feasibility of breeding the fish. Fertilized eggs for larviculture were obtained by induced spawning through multiple hormonal injections of the female brooders, followed by artificial fertilization for the greasy grouper and by natural spawning in netcages for the brown‐marbled grouper.For both species, larviculture was divided into three operational stages, i.e., stage 1 (day 0–12), stage 2 (from day 12 to day 24 for the greasy grouper and to day 30 for the brown‐marbled grouper) and stage 3 (day 24 or 30 to metamorphosis). Larvae were transferred to clean tanks after each stage. Total mortality around day 5–8 was common for the greasy grouper. Several modifications, including the feeding with super‐small strain rotifers, intensive feeding of rotifers with Nannochloropsis and the use of an oil‐skimmer, have been made to improve the situation. Two other major problems in larviculture were the high mortality observed after day 25 in the greasy grouper and the high cannibalism from day 35 onwards for the greasy grouper and from day 30 onwards for the brown‐marbled grouper. The shock syndrome exhibited by both species during the periods made culling of the fish impossible.Based on the spawning and larval characteristics, brown‐marbled grouper is considered a better potential species for large scale fry production than the greasy grouper.
Economic Analysis of Japanese Household Demand for Salmon
Authors: Wessells Cathy Roheim , Wilen James E. 
Published: April 2007

AbstractThe recent glut of both wild and farmed salmon in world markets has forced producers to become aware of the need to expand their marketing efforts to ensure that demand is not outpaced by supply resulting in a further decline in prices. Japan has been a major market for wild salmon, particularly sockeye salmon from North America, since the introduction of the 200 mile Exclusive Economic Zone. As farmed supplies have continued to increase, exporters such as Norway and Chile have turned their attention to this market as well. Up until now, most of the farmed salmon exported to Japan has been targeted to the restaurant market. If exporters wish to expand their market in Japan, they may focus also on the retail market. Prior to any assessment of the potential of the retail market for fresh farmed salmon, it is useful to understand the role that salmon plays in Japanese household seafood consumption.This paper examines household consumption patterns of salmon in Japan. An econometric model is presented which estimates household demand for fresh and salted salmon focusing specifically on the effects of seasonality, regional location, and prices of other seafood products. Two systems of demand equations, one for each of two regions of Japan, are specified and estimated using monthly data on prices and expenditures to capture the effects on household demand for 12 seafood products. Results indicate that seasonality plays a significant role in the demand for many seafood products, particularly fresh and salted salmon. In addition, these seasonal effects are not necessarily the same between regions of Japan. Salmon competes with different seafood products during different times of the year. A rich variety of factors should be considered when marketing fresh aquacultured salmon in the Japanese retail market.
A Practical Calcium Hardness Criterion for Channel Catfish Hatchery Water Supplies
Authors: Tucker Craig S. , Steeby James A. 
Published: April 2007

AbstractThree pairs of brood channel catfish Ictalurus punctatus were induced to spawn in aquaria supplied with flowing water from a reservoir filled with ground water (calcium hardness = 110 mg/L as CaCO3= 44 mg/L as calcium). Fertilized egg masses were allowed to incubate in aquaria for 6 h and each mass was then split into five portions. The five portions were then allowed to hatch and the resulting sac fry developed in waters with calcium hardnesses of 0, 1, 5, 10, or 100 mg/L as CaCO3 (0, 0.4, 2, 4, or 40 mg/L as calcium). Test waters were prepared from distilleddeionized water and reagent‐grade chemicals; tests were conducted using static‐renewal conditions. Survival from hatch to onset of exogenous feeding (“swim‐up”) averaged 62% in calcium‐free water and 98% at all other calcium hardness levels. Wet weight gain, dry weight loss, and resistance to environmental hypoxia were significantly affected (P < 0.05) by environmental calcium levels: best growth, yolk utilization rate (indicated by changes in dry weight and visual observation), and tolerance to low dissolved oxygen concentrations were found at calcium hardnesses of 10 and 100 mg/L as CaCO3. Based upon these results, a minimum calcium hardness of 10 mg/L as CaCO3 (4 mg/L as calcium) is recommended for channel catfish hatchery water supplies.
Integrated Duck‐cum‐Fish Farming in Bangladesh
Authors: Latif Muhammad A. , Alam Mohammad J. , Rahman Mohammad A. 
Published: April 2007

AbstractAn experiment on integrated duck‐cum‐fish farming was conducted in 11 ponds of 0.1 ha each at the Fisheries Research Institute, Mymensingh, Bangladesh. Khaki Campbell layer ducks Anas platyrhychos were housed directly over the pond water surface at 200, 400 and 500 dncks/ha. Each density had three replicate ponds and two ponds had no ducks. Fish fingerlings were stocked at a total density of 8,850/ha. The species composition was silver carp Hypophthalmicthys molitrix 33.9%; catla Catla catla 12.4%; rohu Labeo rohita 18.1%; mrigal Cirrhina mrigala 28.8%. grass carp Ctenopharyngodon idella 1.4% and sor puti Puntius gonlonotus 5.4%. The fish were not given any supplemental feed, and the ponds were not fertilized except for the split duck feed and duck manure falling directly into the ponds. Ducks were fed with a feed formulated from locally available ingredients.After one year the fish were harvested. The yield of fish increased with an increase in duck density. Highest net fish production of 4,250 kg/ha/yr was obtained from ponds with 500 ducks/ ha, compared to 490 kg/ha/yr from the control ponds. Manure of each duck contributed a net fish yield of 6.9–7.5/yr. Average egg production was 237 eggs per female duck per year. Economic analysis of the technology showed a net profit of about 100% of the total costs, indicating the economic viability of the technology.
Effects of Salinity on Hatching and Post‐Hatch Survival of the Australian Red Claw Crayfish Cherax quadricarinatus
Authors: Anson Kevin J. , Rouse David B. 
Published: April 2007

AbstractHatching rate and post‐hatch survival of Australian red claw crayfish Cherax quadricarinatus decreased with an increase in seawater salinity. An LC50 of approximately 11 g/L was determined for juvenile survival in seawater through 15 d. Sodium chloride salinity levels as low as 1 g/L killed all crayfish within 15 d. Tolerance of young red claw to higher levels of seawater salinity than sodium chloride salinity may he due to the concentration of other ions in seawater.
Significance of Habitat and Stock Re‐Testing for Enhancement of Natural Fisheries: Experimental Analyses with Queen Conch Strombus gigas
Authors: Stoner Allan W. 
Published: April 2007

AbstractThe queen conch Strombus gigas is a large, commercially important gastropod mollusc native to the Caribbean region that has become severely depleted because of overfishing and habitat destruction. Over the last 10 yr attempts have been made to rehabilitate conch stocks through releases of hatchery‐reared stocks, but successes have been few. Some of the reasons for high mortality in hatchery‐reared conch are elucidated by recent experiments conducted at Lee Stocking Island in the central Bahamas.Field experiments with juvenile queen conch indicate that sites with similar depths, sediments, and macrophyte cover do not provide equivalent food and shelter for conch. Transplants of conch were successful only in sites known to be historically significant as nursery grounds. While small‐scale transplants can be used to screen potential outplant sites, only comprehensive understanding of the habitat requirements, behavior, feeding ecology, and predator‐prey relationships will lead to long‐term enhancement of fishery stocks. Differences in morphology, behavior, and habitat utilization between wild and hatchery‐reared stocks also had significant effects on the survivorship and growth of outplanted stock. Therefore, hatcheries must develop culture methods that do not reduce the natural fitness of wild stock. Successful enhancement of natural fisheries through outplanting of hatchery‐reared stocks depends upon: 1) development of hatchery animals sufficiently well adapted to survive in the field; and 2) release of the stock in suitable habitats at the optimal time. Close linkage between laboratory and field research, and hatchery operators will he necessary for the ultimate success of stock enhancement efforts.
Tissue Distribution of Enrofloxacin in Fingerling Rainbow Trout Oncorhynchus mykiss Following Different Doses of Oral Administration
Authors: Hsu Hui‐Min , Wooster Gregory A. , Bowser Paul R. 
Published: April 2007

AbstractRainbow trout Oncorhynchus mykiss were fed a ration medicated to provide enrofloxacin (Baytrilo®, Bayer) at 2.5, 5.0, or 10.0 mg drug per kg fish per d either 5 or 10 d. Tissue Concentrations of enrofloxacin were measured in liver, kidney, muscle, skin, and serum during the medication period, and thereafter for a total of 30 d. Highest tissue concentrations were observed in fish medicated with 5 mg enrofloxacin per kg fish per d for 10 d. Tissue concentrations of anitmicrobial activity were found to exceed minimum inhibitory concentrations of enrofloxacin for several isolates of Aeromonas salmonicida and Renibacterium salmoninarum. Lower than expected tissue concentrations were observed for the 10 mg per kg fish per d doses, perhaps due to a lack of acceptance of the medicated ration. The results support evaluation of a 5 mg per kg fish dose to treat bacterial infections of salmonids under field conditions.
Spat Collection and Growth to Commercial Size of the Tehuelche Scallop Aequipecten tehuelchus (D'Orb.) in the San Matias Gulf, Patagonia, Argentina
Authors: Narvarte Maite A. 
Published: April 2007

AbstractStudies on larval settlement and growth of the commercial scallop Aequipecten tehuelchus were carried out over a 2‐yr period in San Matias Gulf, Argentina. Gonadal index was used to indicate spawning and spat collectors were deployed when spawning began. Artificial spat collectors (mono‐filament bags filled with thin shrub branches) were placed at a depth of 25 m in two areas of the Gulf during two seasons (1989–1990 and 1991–1992). Maximum settlement occurred by mid‐February during the first season and by mid‐January in the second season. Larger numbers of spat were found in collectors placed near the sea bottom. After settlement, spat were removed and placed in cages for growout. Scallops reached the average commercial size (60 mm shell height) 16 mo later. Mortality rate during the entire period was 10%.
Ecology of Blue‐Green Algae in Aquaculture Ponds
Authors: Paerl Hans W. , Tucker Craig S. 
Published: April 2007

AbstractCyanobacteria (blue‐green algae) in the genera Anabaena, Aphanizomenon, Microcystis, and Oscillatoria often form extensive and persistent blooms in freshwater aquaculture ponds. Bloom‐forming cyanobacteria are undesirable in aquaculture ponds because: 1) they are a relatively poor base for aquatic food chains; 2) they are poor oxygenators of the water and have undesirable growth habits; 3) some species produce odorous metabolites that impart undesirable flavors to the cultured animal; and 4) some species may produce compounds that are toxic to aquatic animals. Development of cyanobacterial blooms is favored under conditions of high nutrient loading rates (particularly if the availability of nitrogen is limited relative to phosphorus), low rates of vertical mixing, and warm water temperatures. Under those conditions, dominance of phytoplankton communities by cyanobacteria is the result of certain unique physiological attributes (in particular, N2 fixation and buoyancy regulation) that allow cyanobacteria to compete effectively with other phytoplankton. The ability to fix N2 provides a competitive advantage under severe nitrogen limitation because it allows certain cyanobacterial species to make use of a source of nitrogen unavailable to other phytoplankton. The ability to regulate cell buoyancy through environmentally‐controlled collapse ad reformation of intracellular gas vacuoles is perhaps the primary reason for the frequent dominance of aquaculture pond phytoplankton communities by cyanobacteria. Cyanobacteria that can regulate their position in the water column gain a distinct advantage over other phototrophs in poorly mixed bodies of water. In addition to the physicochemical interactions that influence phytoplankton community dynamics, cyanobacterial‐microbial associations may play an important regulatory role in determining community structure. Cyanobacteria are always found in close association with a diverse array of microorganisms, including eubacteria, fungi, and protozoans. These associations, which in the past have often been viewed as antagonistic, are increasingly seen as mutualistic and may function in a positive manner during bloom development.
Significance of Fish Size‐At‐Release on Enhancement of Striped Mullet Fisheries in Hawaii
Authors: Leber Kenneth M. 
Published: April 2007

AbstractA tag‐release‐recapture study was conducted to evaluate size‐at‐release impacts upon recruitment of cultured, juvenile striped mullet, Mugil cepahlus released in inshore habitats of Oahu, Hawaii, USA. In June and July 1990, 85,848 juvenile mullet were graded into five size groups (ranging from 45 to 120 mm in length), identified with binary‐coded wire tags, and released into two estuaries (2×5 factorial design). Of the tagged fish, 42,822 were released into Kaneohe Bay on the east (windward) coast of Oahu; 43,026 were released into Maunalua Bay on Oahu's dryer south shore. The fish were released into both bays simultaneously. Releases were blocked in time across 5 release lots. To evaluate growth and survival rates of released mullet, both bay systems were sampled monthly with cast nets over a ten‐month period after release. Overall, 733 tagged M. cephalus were recaptured, 277 from Kaneohe Bay and 456 from Maunalua Bay. Overall proportions of tagged fish in samples declined from 33.4% (±25.2%) of the total M. cephalus catch at week 5 to 1.88% (±0.95%) by week 23. From week 23 on, tagged fish averaged 2.09% (±0.23%) of the striped mullet in monthly samples. Within 9 wk after releases, recapture frequencies were clearly skewed in favor of fish that were larger at the time of release. Fish smaller than 70 mm when released were rare or absent in collections within 18 wk after release. This confirms results of a smaller‐scale pilot study in Maunalua Bay and shows that fish size‐at‐release can have a major impact on the success of hatchery releases in marine habitats. Pilot studies to identify minimum fish size‐at‐release should be conducted at all sites targeted for full‐scale marine hatchery releases.
Increased Densities Result in Reduced Weight Gain of Crayfish Orconectes virilis1
Authors: Brown Paul B. , Wilson Keith A. , Wetzel James E. , Hoene Benjamin 
Published: April 2007

AbstractThree independent studies were conducted in which supplemental food was provided to juvenile Orconectes virilis reared at varying densities. One study was conducted in fiberglass tanks (densities of either 13, 27 or 54 individuals/m2) and two were conducted in outdoor pools (densities of either 2.5, 5, 10, 20 or 30 individuals/m2). Crayfish were offered a variety of foods ranging from a formulated diet to agricultural forages. Weight gain of crayfish fed a formulated diet and reared at varying densities was similar in the study conducted in tanks, but survival was significantly lower at the two highest densities (27 and 54/m2). Weight gain, survival and yield decreased as density increased in the studies conducted in outdoor pools. The highest weight gain and survival were at a density of 2.5/m2. Wheat straw was used as the source of nutrients. Use of formulated diets did not result in rapid weight gain when crayfish were reared at higher densities.
Maturation and Reproduction of Pond‐Reared Penaeus schmitti
Authors: Ramos Laida , Espejo Manuel , Samada Soraya , Pérez Lourdes 
Published: April 2007

Abstract Penueus schmitti broodstock was grown from postlarvae in a three‐stage semi‐intensive pond system. Mean weight after 10.5 mo was 51.2 g for females and 33.8 g for mnles. Reproductive response was evaluated in two studies. The first study was conducted with unilaterally ablated or unablated females and males with ejaculated or non‐ejaculated spermntophores. The best response was achieved with ablated females and with non‐ejaculated males (0.87 spawas/maturation tank per d and 22.254 nauplii/maturation tank per d). The second study compared the reproductive response of captive ablated females mated with pond‐reared males or wild males. More nauplii were produced from wild males (78,583 nauplii/maturation tank per d) than from pond‐reared males (57,777 nnuplii/tank per d). The reproductive culture cycle of P. schmitti has been closed for the first time in Cuba on a commercial scale with the collection and stocking of postlarvae of the F1 generation.
The Annual Reproductive Cycle of the White BassMorone chrysops
Authors: Berlinsky David L. , Jackson Leslie F. , Smith Theodore I. J. , Sullivan Craig V. 
Published: April 2007

AbstractThe gametogenic cycle of the white bassMoronc chrysopswas characterized for one year at monthly intervals by measuring circulating levels of the sex steroid hormones testosterone (T) and 11‐ketotestosterone (11‐KT) in males, and 17β‐estradiol (E2) and T in females. Vitellogenin (VTG), the egg yolk precursor, was also measured in female blood plasma. Gonadal status of individual fish was assessed by histological evaluation, measurement of oocyte diameters, and spermintion response. At the onset of vitellogenesis (October), blood plasma levels of E2and T were low, but increased significantly as the spawning period (March‐April) approached and oocytes attnined their maximum diameter. All stages of oocyte development were observed in mature females, indicating that the white bass is a multiple‐clutch, groupsynchronous spawner. Androgen levels increased in males throughout the reproductive cycle and reached maximal levels during the spawning period. The increase in androgens coincided with sperm production and spermintion in males. The circannual endocrine and gonadal development patterns observed in white bass were similartothose of other members of genusMoronc.
The Effect of Live and Artificial Diets on Growth, Survival, and Trypsin Activity in Larvae of Penaeus indicus
Authors: Kumlu Metin , Jones D. A. 
Published: April 2007

AbstractIn this study, partial and total replacement of live diets (microalgae and Artemia nauplii) with microencapsulated diets (MED) are demonstrated for larval culture of P. indicus. Slower growth and lower survival rate of larvae fed experimental MED were significantly improved by a supplement of 15 cells/μL frozen mixed algae (1:2, Tetrtaselmis and Skeletonema) during protod stages (PZ1–PZ3). This low level of algal supplement to MED resulted in survival (85–92%) equal to that obtained from control live diets (91%) during protod stages. These significant improvements in larval growth and survival are likely to be due to higher larval digestive enzyme activities and hence more efficient digestion of the artificial diet by the larvae. Like other penaeids, P. indicus larvae show high total and tissue trypsin activities during PZ stages, with a peak at mysis stage 1 (M1), and a decrease during subsequent stages when fed on conventional live diets of algae followed by Artemia during mysis stages. Larvae fed 15 ceUs/μL mixed frozen algae in addition to MED demonstrated a significantly higher trypsin activity throughout herbivorous larval stages in comparison to larvae fed solely on MED. A freeze dried alga Rhinomonas reticulata incorporated into a MED at 23Vo (v/v) induced larval trypsin activity equal to that produced by live algae. Hence, the algal substances, which trigger digestive enzyme production, may be retained within the microcapsules. At mysis stages, however, addition of live prey (one Artemia/mL) to cultures fed with MED significantly improved growth and survival although it depressed trypsin activity. For mysis stages it appears that the use of predigested ingredients is necessary to improve the digestibility of formulated diets.