Home About us Contact
|
Home About us Contact | ||
|
|
||
Hatchery
Kinds of Hatchery Terms modified by Hatchery Selected AbstractsSturgeons in Greece: a reviewJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2008I. Paschos Summary In the past, sturgeons were practically unknown in Greece, both to the public and to scientists, the latter not having had the opportunity to study wild populations of the four native species. Populations of stellate sturgeon (,cipenser stellatus Pallas, 1771), Adriatic sturgeon (Acipenser naccarii Bonaparte, 1836), and beluga sturgeon (Huso huso L., 1758) gradually collapsed by the end of the 1970s. Only the River Evros (Thrace, N.W. Greece) sustained a small fishery and caviar canning operation with European sturgeon (A.,sturio L., 1758) until 1975. Collapse of stocks was mainly attributed to overfishing, pollution and damming. Sturgeons became widely known after initial farming efforts by the Municipal Hatchery at Lake Ioannina in 1992. Broodstock or fertilized eggs of species with high aquaculture potential, such as sterlet (Acipenser ruthenus L., 1758), Russian sturgeon (Acipenser gueldenstaedtii Brandt, 1833), bester hybrid (A.,ruthenus ×H. huso), paddlefish (Polyodon spathula Walbaum, 1792), Siberian sturgeon (Acipenser baerii Brandt, 1869) and white sturgeon (Acipenser transmontanus Richardson, 1836) were imported into Greece between 1992 and 2004. Hatchery technology, larval rearing and production systems are reviewed in this paper and, despite problems, past and present efforts appear to meet a particular interest of the aquaculture sector as well as of those interested in the restoration of wild stocks. [source] Bivalve Shellfish Quality in the USA: From the Hatchery to the ConsumerJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2010Daniel P. Cheney Shellfish aquaculture has had a long tradition in Asia, Europe, and the western USA, but it is only within the past century that significant cultural and handling practices have been identified, developed, and introduced to improve and enhance shellfish food quality. Shellfish are now being marketed with an emphasis on product quality, product variety, reduced human health risk, and improved ease of preparation. Aquacultured bivalve shellfish products must now have the food quality characteristics of other high-quality seafood products and must meet accepted standards of taste, color, texture, and odor. This review summarizes current efforts within the shellfish industry to improve the food quality of aquacultured bivalve shellfish in the following focus areas: (i) genetic selection and controlled breeding; (ii) production tools; (iii) food safety protection and enhancement; and (iv) processing and creative marketing efforts, with major emphasis on the US shellfish aquaculture sector. [source] Inbreeding Effects on Hatchery and Growout Performance of Pacific White Shrimp, Penaeus (Litopenaeus) vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2008Dustin R Moss In animal breeding programs, selection coupled with a narrow genetic base can cause high levels of inbreeding to occur rapidly (in one or two generations). Although the effects of inbreeding have been studied extensively in terrestrial animals and to a lesser extent in aquaculture species, little is known about the effects of inbreeding on penaeid shrimp. The objective of this study was to investigate the effects of inbreeding on hatchery and growout performance of the Pacific white shrimp, Penaeus vannamei. The experiment was conducted over 2 yr, and data from two successive generations (G2 and G3) of inbred (sibling,sibling mating) and outbred families were analyzed. There were 11 inbred and 12 outbred families in G2 and 9 inbred and 10 outbred families in G3. Inbreeding coefficients (F) for outbred and inbred families were 0.00 and 0.25, respectively, for G2 and 0.00 and 0.375, respectively, for G3. Growth rates for outbreds and inbreds were similar in both G2 and G3. Hatch rate for inbred families was 33.1% lower than for outbred families in G2 and 47.1% lower in G3. Inbreeding depression (IBD) (relative change in phenotype per 0.1 increase in F) ± 95% CI for hatch rate was ,12.3 ± 10.1%. Hatchery survival for inbred families was 31.4% lower than for outbred families in G2 and 38.8% lower in G3. IBD for hatchery survival was ,11.0 ± 5.7%. Growout survival was 1.9% lower for inbred families than for outbred families in G2 and 19.6% lower in G3. IBD for growout survival was ,3.8 ± 2.9%. There was also a significant linear relationship between IBD estimates for survival traits and mean outbred survival. At high outbred survival, IBD was low (e.g., growout survival in G2), but IBD appeared to become more severe when outbred survival was lower. This suggests that stress (related to environment and/or life stage) may worsen IBD for survival traits. Results also indicate that moderate to high levels of inbreeding (>10%) should be avoided in commercial shrimp hatcheries because the cumulative effect of IBD on hatch rate and hatchery survival will significantly reduce postlarvae production. Thus, IBD can be significant enough to justify the use of inbreeding as a germplasm protection strategy (under certain scenarios) for genetic improvement programs. [source] Size Economies of a Pacific Threadfin Polydactylus sexfilis Hatchery in HawaiiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2002Lotus E. Kam A spreadsheet model has been developed to determine the viable scale for a commercial Pacific threadfin Polydactylus sexfilis hatchery in Hawaii. The production scheme is modeled after current practices performed at the Oceanic Institute in Waimanalo, Hawaii. For a hatchery enterprise producing 1.2 million fry per year, the cost associated with raising one 40-d-old 1.00-g fry is estimated at 22.01ø. The largest variable costs are in labor and supplies, which comprise 49% and 9% of the total production cost. The combined annualized fixed cost for development and equipment is approximately 12% of total production cost. At a sale price of 25ø per fry, the 20-yr internal rate of return (IRR) is 30.63%. In comparison to the 22.01ø unit cost for 1.2 million fry production, analyses of smaller enterprises producing 900,000 and 600,000 fry per year reflected significant size diseconomies with unit costs of 27.41ø and 38.82ø, respectively. Demand to support a large scale Pacific threadfin commercial hatchery is uncertain. Since smaller scale commercial hatcheries may not be economically feasible, facilities may seek to outsource live feed production modules or pursue multiproduct and multiphase approaches to production. An analysis of the production period length, for example, indicates that the cost for producing a day-25 0.05-g fry is 17.25ø before tax and suggests the financial implications of transferring the responsibility of the nursery stage to grow-out farmers. Evaluation of the benefits gained from changes in nursery length, however, must also consider changes in facility requirements, mortality, and shipping costs associated with transit, and the growout performance of and market demand for different size fry. Sensitivity analyses also indicate the potential cost savings associated with the elimination of rotifer, microalgae, and enriched artemia production. Managerial decisions, however, must also consider the quality and associated production efficiencies of substitutes. [source] They've Gotta Learn Something Unless They're Just Out To Lunch: Becoming an Expert in a Salmon HatcheryANTHROPOLOGY OF WORK REVIEW, Issue 1-2 2004Yew-Jin Lee First page of article [source] Interspecific Effects of Artifically Propagated Fish: an Additional Conservation Risk for SalmonCONSERVATION BIOLOGY, Issue 6 2002Phillip S. Levin We tested the hypothesis that hatchery-reared steelhead salmon ( Oncorhynchus mykiss) released into the Snake River Basin negatively affect the survival of wild Snake River steelhead and chinook ( O. tshawytscha) salmon. Because climatic conditions can influence salmon survival, we included an index of the El Niño,Southern Oscillation ( ENSO) as a covariate in our analyses. Based on time series of hatchery releases and rates of smolt-to-adult survival, we demonstrate that the survival of wild chinook salmon is negatively associated with hatchery releases of steelhead. The state of the ( ENSO) did not affect the strength of this relationship. We observed no relationship between survival of wild steelhead and steelhead hatchery releases. Our results suggest that industrial-scale production of hatchery fish may hinder the recovery of some threatened salmonids and that the potential interspecific impact of hatcheries must be considered as agencies begin the process of hatchery reform. Resumen: Por más de 120 años, las granjas han liberado números enormes de salmones del Pacífico para compensar las numerosas agresiones humanos a sus poblaciones, sin embargo, los impactos ecológicos de este esfuerzo masivo son poco entendidos. Evaluamos la hipótesis de que la trucha cabeza de acero ( Oncorhynchus mykiss) criada en granjas y liberada en la cuenca del Río Snake afecta negativamente la supervivencia de truchas cabeza de acero y salmones chinook ( O. tshawytscha) silvestres. Puesto que las condiciones climáticas pueden influir sobre la supervivencia del salmón, incluimos un índice de la Oscilación del Niño del Sur como covariable del análisis. En base a series de tiempo de las liberaciones de las granjas y las tasas de supervivencia hasta adulto de peces migrantes al mar, demostramos que la supervivencia del salmón chinook silvestre está negativamente correlacionada con las liberaciones de truchas cabeza de acero de las granjas. El estado de la Oscilación del Niño del Sur no afectó el grado de correlación. No observamos relación alguna entre la supervivencia de las truchas silvestres y las liberaciones de las granjas. Nuestros resultados sugieren que la producción a escala industrial de peces de granja puede obstaculizar la recuperación de algunos salmónidos amenazados y que el impacto interespecífico potencial de las granjas debería ser considerado en cuanto las agencias inicien el proceso de reforma de las granjas. [source] The future of stock enhancements: lessons for hatchery practice from conservation biologyFISH AND FISHERIES, Issue 2 2002Culum Brown Abstract The world's fish species are under threat from habitat degradation and over-exploitation. In many instances, attempts to bolster stocks have been made by rearing fish in hatcheries and releasing them into the wild. Fisheries restocking programmes have primarily headed these attempts. However, a substantial number of endangered species recovery programmes also rely on the release of hatchery-reared individuals to ensure long-term population viability. Fisheries scientists have known about the behavioural deficits displayed by hatchery-reared fish and the resultant poor survival rates in the wild for over a century. Whilst there remain considerable gaps in our knowledge about the exact causes of post-release mortality, or their relative contributions, it is clear that significant improvements could be made by rethinking the ways in which hatchery fish are reared, prepared for release and eventually liberated. We emphasize that the focus of fisheries research must now shift from husbandry to improving post-release behavioural performance. In this paper we take a leaf out of the conservation biology literature, paying particular attention to the recent developments in reintroduction biology. Conservation reintroduction techniques including environmental enrichment, life-skills training, and soft release protocols are reviewed and we reflect on their application to fisheries restocking programmes. It emerges that many of the methods examined could be implemented by hatcheries with relative ease and could potentially provide large increases in the probability of survival of hatchery-reared fish. Several of the necessary measures need not be time-consuming or expensive and many could be applied at the hatchery level without any further experimentation. [source] The relative roles of domestication, rearing environment, prior residence and body size in deciding territorial contests between hatchery and wild juvenile salmonJOURNAL OF APPLIED ECOLOGY, Issue 3 2003Neil B. Metcalfe Summary 1Interactions between captive-reared and wild salmonids are frequent because hatcheries annually rear millions of fish for release in conservation programmes while many thousands of domesticated fish escape from fish farms. However, the outcome of competition between captive-reared and wild fish is not clear: wild fish may be smaller and less aggressive than hatchery fish, but they have more local experience and a prior residence advantage. Moreover, it is important to know whether any competitive differences are genetic (due to the process of domestication) or due to the rearing environment. 2We therefore examined the factors influencing competition for feeding territories in juvenile Atlantic salmon. We studied the effect of domestication by using three independent stocks of both domesticated and wild-origin fish, all of which were reared in a common hatchery environment. We also used fish from the same wild stocks that had been living in the wild. Territorial contests were staged in stream tank compartments between pairs of fish differing in origin or rearing environment; the relative importance of body size and prior residence was also assessed. 3All three stocks of domesticated fish were generally dominant over wild-origin fish when both had been raised in a common hatchery environment. If the wild-origin fish were given a 2-day period of prior residence on the territory this asymmetry in dominance was reversed. However, domesticated fish did not gain any additional advantage from being prior residents. The relative body size of the two contestants had a negligible effect on contest outcomes. 4Truly wild fish (i.e. those of wild origin that had also grown up in the wild) were generally dominant over domesticated or wild-origin fish that had been hatchery-reared. Differences in body size between contestants had no effect on the outcome. 5Synthesis and applications. These results show that, while juvenile farmed Atlantic salmon are inherently more aggressive than wild-origin fish, the hatchery environment reduces their ability to compete for territories with wild resident fish. Rearing salmon in conventional hatcheries for later release into the wild where natural populations already exist may not be a prudent conservation measure; it is preferable to plant eggs or first-feeding fry rather than attempt to ,help' the fish by rearing them through the early life stages. [source] Sturgeon aquaculture in China: status of current difficulties as well as future strategies based on 2002,2006/2007 surveys in eleven provincesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2009By R. Li Summary A nationwide survey in July and August 2007 employed a representative sample of Chinese sturgeon farms from 2002,2006/2007, including data from previous surveys and official statistics dating back to 1998, showing that the development of China's sturgeon aquaculture has progressed steadily in the past few years. Acipenser baerii and Amur hybrids (Acipenser schrenckii × Huso dauricus) have become the dominant cultured species, accounting for 80% of total production. Production centers moved from the southeastern coast towards the midwestern inland provinces, where cold freshwater resources are available in abundance. The paper presents production trends as well as the price structure for commercial fish/meat and juveniles in the various provinces and also considers import and export data for products, fertilized eggs and fingerlings. Results show that: (i) production of juveniles in hatcheries has risen only slightly during the survey period; (ii) the number of larvae obtained from the wild gradually declines each year; (iii) the price for commercial fish/meat drastically declined between 1998 to 2002, but remained stable from 2002 to 2007; and (iv) total production from the 83 surveyed farms was almost stable from 2002 to 2007. Major problems influencing sustainable development of sturgeon aquaculture were identified, including: (i) insufficient domestic supply of larvae and the ban for commercial use of A. sinensis; (ii) disorganized hybridization; (iii) the potential threat to the genetics of natural stocks in the Yangtze River; (iv) diseases originating from environmental pollution and poor-quality fish feed; (v) limited domestic markets; (vi) low volume of sturgeon export due to lack of intensive processing; and (vii) lack of organizational structure in the industry. [source] Comparative analysis of cost factors in sturgeon fingerling production in Iranian hatcheries (2000,2004)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2009H. Salehi Summary Production cost analysis in aquaculture is an essential exercise to assist farm managers. Economic assessment of a farm operation also provides the basis to formulate governmental aquaculture and enhancement policies in many regions. The present study employed questionnaires and interviewed managers while also using governmental statistics to gain insight into production cost variables in Iranian sturgeon hatcheries. Within a decade, production of sturgeon fingerlings for release and stock enhancement increased in Iran to more than 21 million fingerlings by 2004. Costs and contributions of various production factors were determined using data obtained from a questionnaire involving all hatcheries between 2000 and 2004. A team of experts completed the questionnaire data sets while conducting interviews at all sturgeon centres and other related departments. From 2000 to 2004 the contribution of A. persicus was 79% of the total number of sturgeon fingerlings produced followed by A. nudiventris with 7.5% and Huso huso with 6.6%. Among the various expenditures between 2000 and 2004, the costs for permanent and part-time employees contributed the greatest share of total costs, averaging 44%, with a noticeable declining trend from 51% in 2000 to 36% in 2004. Obtaining and incubating fertilized eggs averaged 22% of total costs, increasing during the same time period from 6 to 35%, respectively. On average, the 2000,2004 production cost for a single sturgeon fingerling was estimated at Rials 1667 (US$ 0.20), increasing from Rials 992 (US$ 0.12) to Rials 2623 (US$ 0.29) over these 4 years. Permanent staff at a hatchery was determined as being the principal cost, followed by costs for obtaining fertilized eggs (including broodstock handling). Over the 5-year study period the results indicated that costs for part-time labour declined yearly and, conversely, the costs of obtaining broodstocks as well as fertilizing and incubating eggs increased. Considering the background of hatchery production and stock enhancement of sturgeon species and the results of fishing data, it is possible to arrive at a first estimate of the potential contribution of Persian sturgeon farming to the total catch in Iranian waters; it is assumed that these increases were most likely through stock enhancement. [source] Pathological and epidemiological observations on rickettsiosis in cultured sea bass (Dicentrarchus labrax L.) from GreeceJOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2004F. Athanassopoulou Summary A systemic infection of a Rickettsia -like organism (RLO) in cultured sea bass is described for the first time. In hatcheries, clinical signs were lethargy, inappetence and discoloration. Twenty days after transfer to sea cages from hatcheries where the disease existed, fish showed erratic and abnormal swimming behaviour, loss of orientation, and lethargy. Cumulative mortality in colder months of the year reached 30% in hatcheries and 80% in cages. Surviving fish in cages did not show any clinical signs of RLO infection in the subsequent year. Evidence for a systemic distribution of RLO was supported by histolopathological lesions in both infected hatchery and caged fish, where the lesion profile included cranial sensory, central nervous, integumental and alimentary organ systems. Intracranial lesions were primarily characterized by an ascending histiocytic perineuritis and necrotizing congestive meningoencephalitis, with evidence for transfer of infective agents across the blood,brain barrier confirmed by the presence of RLOs within capillary endothelium and histiocytes in inflamed regions of the optic tectum and the cerebellum. In the most severe cases, infection spread to the statoacoustical (semicircular) canal system and the ependymal lining of ventricles, with marked rickettsial-laden histiocytic infiltration of the canal lumen. Integumental lesions were restricted to the oral submucosa, nares and integumental dermis of the cranium. Alimentary lesions were noted in both the liver parenchyma and mucosa/submucosa of the stomach. In all affected organs the RLOs were found by immunohistochemistry to be related to Piscirickettsia salmonis. [source] More effective induction of spawning with long-acting GnRH agonist in the shi drum, Umbrina cirrosa L. (Sciaenidae, Teleostei), a valuable candidate for Mediterranean maricultureJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2002A. Barbaro Three experiments of spawning induction in shi drum, Umbrina cirrosa L., were performed in six different commercial Italian hatcheries from May to August (water temperatures: 19,29 °C; salinity: 21,37 p.p.t.). In the first experiment, 119 females (1,4.7 kg), subdivided into 29 lots, were injected with a single dose (2, 5, 8, 10, 15 and 20 ,g kg,1 body weight) of short-acting gonadotropin- releasing hormone agonist (GnRHa-S), des-Gly10,[D-Ala6]-LH-RH ethylamide. In the other two experiments, 85 females (0.7,5.8 kg), subdivided into 22 and four lots, were treated with one (40 or 80 ,g kg,1) or three doses (40 ,g kg,1) of long-acting GnRHa (GnRHa-L), respectively. GnRHa-S stimulated spawning in 69% of the 29 treated lots; the number of eggs laid reached a maximum of 130 000 and a weighted mean of 29 200 total eggs kg,1. GnRHa-L elicited a spawning response in 95% of the 22 one-dose treated lots; the number of laid eggs was higher than with GnRHa-S, reaching a maximum of 213 100 and a weighted mean of 59 400 total eggs kg,1. The yield of developing embryos in 67% of the single GnRHa-L treatments was higher (sometimes up to three times) than with GnRHa-S. Triple treatments of the four lots of females with GnRHa-L always resulted in spawning responses; the best result corresponded to a number of total laid eggs of 358 900 eggs kg,1 with a yield of 177 300 developing embryos. [source] Bacteriological study of shrimp, Penaeus monodon Fabricius, hatcheries in IndiaJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2001Shrimp hatcheries often face problems of mortality caused by diseases. To understand the bacteriological status of shrimp, Penaeus monodon Fabricius, hatcheries in India, a study of hatchery water at different points was conducted in several hatcheries located along the east and west coast of India. The species composition of the bacterial flora was also determined. The total plate counts of raw sea water on tryptic soya agar ranged from 102 to 104 ml,1, whereas it ranged from 104 to 106 ml,1 in larval tanks. In the larval tanks, the proportion of Vibrio species ranged from 50% to 73%, as compared to 31% in raw sea water. A mixed bacterial flora was observed in hatchery water; however, in the larval tanks, the flora in the larvae was predominantly made up of Vibrio species. A few of the tested Vibrio isolates were non-virulent to shrimp larvae under experimental conditions. Over 90% of the strains were resistant to amoxycillin, ampicillin, cephalexin, cephazolin, cloxacillin and sulphafurazole. Most strains showed sensitivity to tetracycline, chloramphenicol, and quinolones such as norfloxacin and ciprofloxacin. [source] Genetic quality of domesticated African tilapia populationsJOURNAL OF FISH BIOLOGY, Issue 2004R. E. Brummett Anecdotal and empirical evidence exists for substantial (up to 40%) declines in growth among Oreochromis populations domesticated in both large and small-scale fish farms in Africa. These declines are at least partly attributable to poor genetic management, including inadvertent selection, inbreeding, bottle-necks and founder effects. Due to restricted cash flow and investment capital, genetic management and selective breeding for the improvement of domesticate populations are difficult for small-scale farmers, but feasible on larger-scale farms. In managing domesticated gene pools, feral populations can serve as a broodstock reservoir, making the use of indigenous species advantageous. A development model of large-scale hatcheries producing selected lines of sex-reversed, indigenous tilapia for sale to smaller-scale farmers is proposed as a solution to the problems of poor genetic management in African aquaculture. [source] Environmental enrichment and prior experience of live prey improve foraging behaviour in hatchery-reared Atlantic salmonJOURNAL OF FISH BIOLOGY, Issue 2003C. Brown Atlantic salmon salmo salar L. parr were reared for 3 months under standard hatchery conditions or in a structurally enriched tank (containing plants, rocks and novel objects). Half of each of these fish had prior exposure to live prey in the form of live bloodworm while the other half were fed hatchery-pellets. After 12 days all fish were tested on a novel live prey item (brine shrimp). A significant interaction between the two factors (prior exposure to live prey and rearing condition) revealed that foraging performance was only enhanced in fish that had been reared in a complex environment and exposed to live prey. It appears that the ability to generalize from one live prey type to another is only enhanced in fish that had been reared in an enriched environment. The findings support the assertion that the provision of enriched environments in combination with exposure to live prey prior to release may significantly improve the post-release survival rates of hatchery-reared fishes. As both the environmental enrichment and the prior foraging experience procedures were comparatively simple, the provision of such pre-release experiences are likely to prove cost effective to hatcheries. [source] Macrobrachium rosenbergii nodavirus infection in M. rosenbergii (de Man) with white tail disease cultured in TaiwanJOURNAL OF FISH DISEASES, Issue 6 2008C S Wang Abstract White tail disease (WTD) is a serious problem in Macrobrachium rosenbergii hatcheries and nursery ponds in Asia. The causative agents have been identified as M. rosenbergii nodavirus (MrNV) and its associated extra small virus. This is the first report demonstrating MrNV virus in M. rosenbergii displaying WTD signs in Taiwan by reverse transcriptase-polymerase chain reaction (RT-PCR). Amplified fragments of 850 and 425 bp for RNA-1 and RNA-2 of MrNV, respectively, were obtained by RT-PCR. RT-PCR products of about 850 and 1121 bp for RNA-1 and RNA-2 of MrNV were also obtained using different primer pairs. The amplicons were individually cloned into pGEM-T vector and sequenced. Using this recombinant plasmid of MrNV RNA-2 as DNA template, the non-radioactive DNA probes were prepared by PCR amplification with DIG,11-dUTP. The probes were used to successfully detect MrNV infection in the striated muscle tissues of WTD-diseased prawns using in situ hybridization. The 1121 bp genomic fragment of RNA-2 of MrNV consisted of a unique open reading frame with 1116 nucleotides, and it encoded a structural protein with 371 amino acids. The nucleotide sequence of the partial genome of MrNV RNA-2 revealed a 97% identity with an Indian isolate. A phylogenetic tree constructed using the nucleotide sequence of the viral capsid gene from insect and fish nodaviruses revealed that the MrNV Taiwan isolate could be interpreted as a new genus within the family Nodaviridae. However, its position showed more affinity with Alphanodavirus than with Betanodavirus. The study confirmed the presence of MrNV infection in freshwater prawns cultured in Taiwan suffering from WTD. [source] Experimental vertical transmission of Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) from brooders to progeny in Macrobrachium rosenbergii and ArtemiaJOURNAL OF FISH DISEASES, Issue 1 2007R Sudhakaran Abstract White tail disease (WTD) is a serious problem in hatcheries and nursery ponds of Macrobrachium rosenbergii in India. Experiments were carried out to determine the possibility of vertical transmission of M. rosenbergii nodavirus (MrNV) and extra small virus (XSV) in M. rosenbergii and Artemia. Prawn broodstock inoculated with MrNV and XSV by oral or immersion challenge survived without any clinical signs of WTD. The brooders spawned 5,7 days after inoculation and the eggs hatched. The survival rate of larvae gradually decreased, and 100% mortality was observed at the post-larvae (PL) stage. Whitish muscle, the typical sign of WTD, was seen in advanced larval developmental stages. The ovarian tissue and fertilized eggs were found to be positive for MrNV/XSV by reverse transcriptase-polymerase chain reaction (RT-PCR) whereas the larval stages showed positive by RT nested PCR (nRT-PCR). In Artemia, reproductive cysts and nauplii derived from challenged brooders were normal and survival rates were within the expected range for normal rearing conditions. The reproductive cysts were found to be positive for MrNV/XSV by RT-PCR whereas the nauplii showed MrNV/XSV-positive by nRT-PCR. The PL of M. rosenbergii fed nauplii derived from challenged Artemia brooders died at 9 days post-inoculum with clinical signs of WTD. [source] Extra small virus-like particles (XSV) and nodavirus associated with whitish muscle disease in the giant freshwater prawn, Macrobrachium rosenbergiiJOURNAL OF FISH DISEASES, Issue 9 2003D Qian Abstract A disease of Macrobrachium rosenbergii, the giant freshwater prawn, farmed in China was recently recorded in Zhejiang, Jiangsu, Shanghai, Guangxi and Guangdong provinces. The clinical sign of the disease, which develops in post-larvae (PL), is a whitish appearance of the muscles, particularly noticeable in the abdomen. Mortalities may reach 100% in some hatcheries. Investigations by transmission electron microscopy after negative staining of diseased PL homogenates showed the presence of two types of viral particles: one, unenveloped, icosahedral in shape, 26,27 nm in diameter, the second, much smaller, about 14,16 nm in diameter, designated extra small virus particle (XSV). The large virus has a genome with two pieces of ssRNA (RNA-1 and RNA-2), of 3 and 1.2 kb, respectively. Hybridization tests confirmed that this large virus is closely related to M. rosenbergii nodavirus (MrNV) which was isolated from diseased prawns in a hatchery in the French West Indies. Its very small size and hypothesized biochemical and biological characteristics suggest XSV is a new type of crustacean virus. As XSV has always been found associated with the larger virus (nodavirus) and is located in muscle and connective cells of diseased animals, it could be an autonomous virus, a helper-type virus or a satellite-like virus. [source] GROWTH OF CULTURED ABALONE, HALIOTIS FULGENS, USING NATURAL ALGAL DIETSJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Pérez-Estrada, C. J.1,2, Serviere-Zaragoza, E.1, Mazariegos-Villareal, A.1, Reynoso-Granados, T.1 & Monsalvo-Spencer, P.1 1Centro de Investigaciones Biológicas del Noroeste (CIBNOR). P.O. Box 128, La Paz, Baja California Sur. 23000. México; 2Universidad Autónoma de Baja California Sur. Carretera al Sur km. 5.5 o 23080 o La Paz, B. C. S. Algal diets have been evaluated and used extensively for the aquaculture of abalone, especially in Japan. In other areas little is known about the nutritional value of the algae that the local abalone consume. In Mexico, regional hatcheries use Macrocystis pyrifera as a main source of natural food. Kelp availability, year round, has not generally been a problem for abalone aquaculturists. Most difficulties occur during severe storms, which may prevent access to kelp beds. El Niño also caused widespread destruction of M. pyrifera. In this study, growth rates of juvenile green abalone Haliotis fulgens, 31.7 " 1.5 mm shell length and 2.5 " 0.2 g body weight were evaluated during 136 days. Juveniles were fed with some of the algae used in regional hatcheries, Macrocystis pyrifera, Egregia menziesii, Eisenia arborea, Porphyra sp. and Ulva sp. Shell length growth rates varied between 2 mm day-1 for Ulva sp. and 18 mm day-1 for M. pyrifera. Body weight rates ranged from no growth for Ulva sp. to 14 mg day-1for E. menziesii. The percent of survival was between 46 and 75 %. Ulva sp. showed the lowest protein content followed by E. menziesii, E. arborea, M. pyrifera and Porphyra sp. [source] Prymnesium parvum: The Texas Experience,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2010Gregory M. Southard Southard, Gregory M., Loraine T. Fries, and Aaron Barkoh, 2010. Prymnesium parvum: The Texas Experience. Journal of the American Water Resources Association (JAWRA) 46(1):14-23. DOI: 10.1111/j.1752-1688.2009.00387.x Abstract:, Golden alga Prymnesium parvum was first identified in Texas during a fish kill investigation on the Pecos River in 1985. Since then golden alga kills occurred sporadically in a variety of waters in the western part of the state until 2001 when the alga became endemic in the Brazos, Canadian, Colorado, Red, and Rio Grande river systems, including the water supplies of two public fish hatcheries, the Possum Kingdom and Dundee state fish hatcheries. The increasing area adversely affected by the alga and frequent massive fish kills heightened public and political awareness and concerns regarding the ecological and economic impacts of P. parvum blooms. The Texas Parks and Wildlife Department (TPWD), the wildlife conservation agency of the state, responded to these concerns with a program to assess the ecological and economic impacts and to develop management options. To date 33 water bodies have been affected and losses are conservatively estimated at 34 million fish valued at US$13 million. Several sport fisheries, including smallmouth bass Micropterus dolomieu, striped bass Morone saxatilis, channel catfish Ictalurus punctatus, and blue catfish Ictalurus furcatus, have been severely affected. Additionally, 26 imperiled fish species occur in the affected water basins and some have been adversely affected. Economic losses associated with reduced fishing and other water-based recreational activities appear considerable. The combined economic losses to three counties (Palo Pinto, Stephens, and Young) surrounding Possum Kingdom reservoir for 2001 and 2003 were estimated at US$2.8 million and US$1.1 million, respectively. This paper describes how the TPWD responded to public and political concerns relative to the emergence of golden alga, its harmful effects to fisheries, and its historic and current statewide distribution. [source] Inbreeding Effects on Hatchery and Growout Performance of Pacific White Shrimp, Penaeus (Litopenaeus) vannameiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2008Dustin R Moss In animal breeding programs, selection coupled with a narrow genetic base can cause high levels of inbreeding to occur rapidly (in one or two generations). Although the effects of inbreeding have been studied extensively in terrestrial animals and to a lesser extent in aquaculture species, little is known about the effects of inbreeding on penaeid shrimp. The objective of this study was to investigate the effects of inbreeding on hatchery and growout performance of the Pacific white shrimp, Penaeus vannamei. The experiment was conducted over 2 yr, and data from two successive generations (G2 and G3) of inbred (sibling,sibling mating) and outbred families were analyzed. There were 11 inbred and 12 outbred families in G2 and 9 inbred and 10 outbred families in G3. Inbreeding coefficients (F) for outbred and inbred families were 0.00 and 0.25, respectively, for G2 and 0.00 and 0.375, respectively, for G3. Growth rates for outbreds and inbreds were similar in both G2 and G3. Hatch rate for inbred families was 33.1% lower than for outbred families in G2 and 47.1% lower in G3. Inbreeding depression (IBD) (relative change in phenotype per 0.1 increase in F) ± 95% CI for hatch rate was ,12.3 ± 10.1%. Hatchery survival for inbred families was 31.4% lower than for outbred families in G2 and 38.8% lower in G3. IBD for hatchery survival was ,11.0 ± 5.7%. Growout survival was 1.9% lower for inbred families than for outbred families in G2 and 19.6% lower in G3. IBD for growout survival was ,3.8 ± 2.9%. There was also a significant linear relationship between IBD estimates for survival traits and mean outbred survival. At high outbred survival, IBD was low (e.g., growout survival in G2), but IBD appeared to become more severe when outbred survival was lower. This suggests that stress (related to environment and/or life stage) may worsen IBD for survival traits. Results also indicate that moderate to high levels of inbreeding (>10%) should be avoided in commercial shrimp hatcheries because the cumulative effect of IBD on hatch rate and hatchery survival will significantly reduce postlarvae production. Thus, IBD can be significant enough to justify the use of inbreeding as a germplasm protection strategy (under certain scenarios) for genetic improvement programs. [source] Size Economies of a Pacific Threadfin Polydactylus sexfilis Hatchery in HawaiiJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2002Lotus E. Kam A spreadsheet model has been developed to determine the viable scale for a commercial Pacific threadfin Polydactylus sexfilis hatchery in Hawaii. The production scheme is modeled after current practices performed at the Oceanic Institute in Waimanalo, Hawaii. For a hatchery enterprise producing 1.2 million fry per year, the cost associated with raising one 40-d-old 1.00-g fry is estimated at 22.01ø. The largest variable costs are in labor and supplies, which comprise 49% and 9% of the total production cost. The combined annualized fixed cost for development and equipment is approximately 12% of total production cost. At a sale price of 25ø per fry, the 20-yr internal rate of return (IRR) is 30.63%. In comparison to the 22.01ø unit cost for 1.2 million fry production, analyses of smaller enterprises producing 900,000 and 600,000 fry per year reflected significant size diseconomies with unit costs of 27.41ø and 38.82ø, respectively. Demand to support a large scale Pacific threadfin commercial hatchery is uncertain. Since smaller scale commercial hatcheries may not be economically feasible, facilities may seek to outsource live feed production modules or pursue multiproduct and multiphase approaches to production. An analysis of the production period length, for example, indicates that the cost for producing a day-25 0.05-g fry is 17.25ø before tax and suggests the financial implications of transferring the responsibility of the nursery stage to grow-out farmers. Evaluation of the benefits gained from changes in nursery length, however, must also consider changes in facility requirements, mortality, and shipping costs associated with transit, and the growout performance of and market demand for different size fry. Sensitivity analyses also indicate the potential cost savings associated with the elimination of rotifer, microalgae, and enriched artemia production. Managerial decisions, however, must also consider the quality and associated production efficiencies of substitutes. [source] Trophic state, fish community and intensive production of salmonids in Alicura Reservoir (Patagonia, Argentina)LAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 4 2001P. F. Temporetti Abstract The Governments of the Provinces located in Patagonia, Argentina, promote the intensive breeding of salmonids in the Andean Patagonian region. Although annual production is low (450 ton ha,1 year,1), some effects are significant. Waste produced by salmonid breeding (feed losses, faeces and excretion) increases nutrient and organic matter concentrations, which cause modifications of water quality, sediments and biota. A consequent risk is the elevation of eutrophication levels. Possible changes in water composition, sediments, algae and wild fish populations were studied. Sites affected by fish farming showed increased nutrient concentration, and phytoplankton and periphyton biomass. Chlorophyll a was similar at both sites (affected and unaffected by fish farm sites). Sediments clearly reflect fish farm waste inputs: total phosphorus and organic matter increased 12-fold and fourfold, respectively. The species present in the gill-net catches were the autochthonous Percichthys trucha, Odontesthes hatcheri, Diplomystes viedmensis, and the introduced salmonids Oncorhynchus mykiss, Salmo trutta, Salmo salar sebago and Salvelinus fontinalis. About 50% of the total catch was salmonids. A major portion of the catch per unit weight was composed of rainbow trout, followed by perch. The catch per unit weight obtained for this reservoir agrees with the range of values previously determined (Quiros 1990) for Patagonian reservoirs. Compared with previous studies by Freyre et al. (1991), a variation in catch composition exists. This consists mainly of an increase in the numbers and condition of O. mykiss and a decrease in P. trucha. Presence of fish that escaped from hatcheries, recognizable by their eroded fins, was observed; particularly in a sampling station near the fish cage systems. Variations in catches could be caused by cyclical changes in fish populations (Wooton 1991), by direct and indirect effects of intensive fish farming, or by a combination of both events, and can only be understood through long-term studies of catch variation. [source] Long-term effects of translocation and release numbers on fine-scale population structure among coho salmon (Oncorhynchus kisutch)MOLECULAR ECOLOGY, Issue 12 2007WILLIAM H. ELDRIDGE Abstract Management actions, such as translocations, reintroductions and supportive breeding, can have both negative and positive effects on population recovery. Several studies have examined the incidence of introgression following such actions, but few studies have explored the effect of release numbers on gene flow between closely related recipient populations. We examined population structure of coho salmon in Puget Sound (Washington State, USA) to evaluate the relationship between the number of individuals transferred between rivers, and the number released within rivers, on inter- and intrariver population divergence. Eleven microsatellite loci were surveyed in 23 hatchery and wild samples collected from 11 rivers within and one hatchery outside Puget Sound. Pairwise genetic divergences between most populations were significant, but the population structure could not be explained by an isolation-by-distance model (Mantel test, P > 0.05). In contrast, we detected significant hatchery influence on population structure. The numbers of fish transferred among rivers between 1952 and 2004 was negatively correlated with differentiation between rivers (partial Mantel test, P = 0.005) but not within rivers (t -test, P = 0.41). Number of fish released from hatcheries that collect broodstock locally was negatively correlated with population structure within rivers (t -test P = 0.002), and between nearby rivers (partial Mantel P = 0.04). Our results indicate that the population structure can, to some degree, be altered by the number of individuals transferred and by local release number of individuals in ongoing artificial propagation programs. The findings presented here emphasize the need to control the number of individuals that are either inadvertently introduced, or are deliberately released under conservation scenarios. [source] The whole amino acid profile as indicator of the nutritional condition in cultured marine fish larvaeAQUACULTURE NUTRITION, Issue 2 2007J.B. CARA Abstract The effect of variations in the amount or quality of food provided on the amino acid profile of larvae, was tested in two marine fish species, the Senegal sole (Solea senegalensis) and the sea bass (Dicentrarchus labrax). The objective was to assess whether such nutritionally suboptimum dietary patterns, which simulate situations that may occur in hatcheries, result in variations in the concentration of one or more amino acids that could be used as indicators of nutritional condition of larvae. Restriction in the normal food ration by 60% had no clear effect on the amino acid profile of sea bass, while the concentration of some amino acids (Arg, Ala and Phe) showed significant variations in sole. Feeding on artificial diets, which have shown their inadequacy a priori, resulted also in no significant effect on the profile of sea bass, but in a dramatic modification of the amino acid profile in sole. In addition, changes in the amino acid profiles considered as a whole were evaluated using the cluster analysis instead of paired comparisons between amino acid concentrations in each treatment. The analysis clearly separated profiles of larvae fed restrictedly or inadequately from their controls, irrespective of the species. This demonstrated the potential value of evaluating whole changes in amino acid profile as nutritional indicator. Besides, it was demonstrated that sensitivity of larvae to nutritional changes that may be reflected in the amino acid profile is greatly conditioned by the species and developmental stage. [source] Barnacle culture: background, potential and challengesAQUACULTURE RESEARCH, Issue 10 2010Daniel A. López Abstract There are approximately a dozen species of commercially interesting barnacles worldwide, some of which have been cultured on a semi-industrial scale. These species are listed and information is provided with regard to geographical distribution, landings and prices. Traditionally, ,goose' barnacles (four species) are considered to be the most important for consumption. World production already stands at 500 tonnes year,1, but this species has not been cultured to date. Some ,acorn' barnacles are also consumed (seven species), with harvest levels per species that do not exceed 200 tonnes year,1 and selling prices that can reach US$17/kg. ,Acorn' barnacle culture on a world scale is still developing. Nevertheless, production has occurred on a semi-industrial scale; specifically, spat have been collected from the wild and grown in suspended systems. Farming trials have focused on two species of acorn barnacles: Austromegabalanus psittacus (Molina 1782) ,picoroco' in Chile and Megabalanus azoricus (Pilsbry 1916) ,craca' in Portugal. The large-scale production of these crustaceans will depend on the optimization of spat collection from the wild and/or the parallel development of mass production technologies for larvae (hatcheries). In addition, further development will be achieved by opening up new markets for commercialization. [source] Reproductive performance and offspring quality of Chinese mitten crab Eriocheir sinensis (H. Milne-Edwards) females fed an optimized formulated diet and the razor clam Sinonovacula constrictaAQUACULTURE RESEARCH, Issue 12 2009Xugan Wu Abstract After feeding female Eriocheir sinensis on an optimized formulated diet or fresh razor clam Sinonovacula constricta for 7 months, their reproductive performance and offspring quality were compared. To evaluate diet nutrient contents, the proximate, fatty acid and amino acid compositions of the formulated diet and the razor clam were analysed. The nutritional value of the diets was determined by assessing survival, gonadosomatic index (GSI) and hepatosomatic index (HSI) of female crabs from both diet treatments, together with the percentage of females that spawned, total egg production per female and fecundity (number of eggs g,1 female wet weight). Furthermore, the quality of eggs and newly hatched larvae from the two dietary treatments were determined using the following parameters: egg diameter, wet weight and dry weight, hatchability, proximate and fatty acid profile of eggs, larval carapace length, resistant to starvation and osmotic shock, larval survival and development to the zoea II stage. Higher protein, phospholipids (PL) and amino acids (AA) contents were found in the razor clam while the formulated diet contains higher levels of ash, total lipid (TL) and 18:1n-9, 18:2n-6 and 22:6n-3 fatty acids. Although female crabs fed the two different diets showed similar reproductive performances, newly hatched zoea I larvae produced by the crabs fed the formulated diet had significantly longer mean carapace length and shorter development time to the zoea II stage under identical culture condition (P<0.05). Moreover, dietary fatty acid appeared to have more significant effects on the fatty acid composition of the hepatopancreas than it did on mature ovaries or eggs. This suggests that the fatty acid profile of mature ovaries is indicative of the specific fatty acid required for ovarian development in E. sinensis. In conclusion, our results show that the optimized formulated diet developed in this laboratory can totally replace the razor clam, a broodstock food widely used in E. sinensis hatcheries in China. This encouraging result should facilitate more reliable hatchery production of this important aquaculture species. [source] Morphometric changes in a strain of the lineage ,Nevada', belonging to the Brachionus plicatilis (Rotifera) complexAQUACULTURE RESEARCH, Issue 8 2009Venetia Kostopoulou Abstract The rotifer Brachionus plicatilis is an important component of aquaculture as a larval feed. Its taxonomic status has been recently re-defined as a species complex, consisting of at least 14 new species/lineages. This study deals with the lineage Brachionus,Nevada', which has been shown to occur in European hatcheries. A strain of B. ,Nevada' was mass cultured using two commonly applied feeding regimes and analysed in terms of its morphometry. A new formula was proposed for the calculation of volume, which can be used as an index of adequacy of rotifers as feed for fish larvae. The results were related to life cycle parameters. The pre-reproductive and reproductive phases were divided into distinct size groups. Differences were also found between the two diets in morphometry and demography. Rotifers of a larger size (yeast-based diet) showed a lower growth rate and a longer reproductive period, lifespan and mean generation time compared with smaller-sized rotifers (Culture Selco® -based diet). In terms of lorica length, the present study's strain of B. ,Nevada' (238.5 ,m) was intermediate between values reported for Brachionus ibericus (193.5 ,m) and B. plicatilis sensu stricto (299 ,m). [source] Probiotics for shrimp larviculture: review of field data from Asia and Latin AmericaAQUACULTURE RESEARCH, Issue 4 2008Olivier Decamp Abstract Disease problems have emerged as major constraints in aquaculture production. The prophylactic application of antibiotics is expensive and detrimental, i.e. selection of bacteria that are drug-resistant or more virulent and the prevalence of drug residues in reared animals. Probiotics, which compete with bacterial pathogens for nutrients and/or inhibit the growth of pathogens, could be a valid alternative to the prophylactic application of chemicals. A mixture of specific Bacillus strains was designed following a research programme on the ability of numerous Bacillus strains to inhibit a range of pathogenic Vibrio strains, to grow under conditions prevailing in shrimp hatcheries and to degrade waste products. These strains were then included in bioassays and challenge tests in order to confirm the lack of toxin production and pathogenicity to humans, target organisms and the environment. Here, we report on the performance of a commercially available mixture of Bacillus strains (SANOLIFE® MIC), using data from Asian and Latin-American hatcheries, with Penaeus monodon (Fabricius 1798) and Litopenaeus vannamei (Boone 1931). These results show that probiotics may be a suitable alternative to the prophylactic use of antibiotics. Obviously, minimizing the risk of vibriosis demands a multi-disciplinary approach, including good hygiene and sanitation measures to reduce the input of potential pathogens, as well as a suitable farm management. [source] Genetic variability of cultured populations of the Pacific abalone (Haliotis discus hannai Ino) in China based on microsatellitesAQUACULTURE RESEARCH, Issue 9 2007Qi Li Abstract The genetic diversity of cultured populations of the Pacific abalone (Haliotis discus hannai Ino) from northern China was analysed using seven microsatellite markers. The microsatellite loci were polymorphic for all the populations, with an average of 8.7 alleles per locus (range 8.0,9.4). The mean observed and expected heterozygosities were 0.547 (range 0.500,0.596) and 0.774 (range 0.754,0.787) respectively. The allelic diversity in terms of number of alleles per locus was considerably lower than that previously found in wild populations (range 21.8,23.0), indicating that bottleneck effects occurred when each population was founded. Significant genetic differentiation among the five cultured populations was shown using Fst and Rst values, and pairwise comparison based on allelic distribution. A neighbour-joining analysis of the genetic distance did not show a consistent relationship between the geographic and the genetic distances, suggesting the existence of exchanges of breeds and eggs between the hatcheries. The results obtained in this study are useful for a number of areas of interest for fisheries management and the aquaculture industry, especially with regard to breeding programmes. [source] | ||||||||||||||||