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Cultured Populations (cultured + population)
Selected AbstractsDivergent selection and realized heritability for growth in the Japanese scallop, Patinopecten yessoensis JayAQUACULTURE RESEARCH, Issue 9 2010Jun Liang Abstract In order to improve the production and accurately estimate response to selection, divergent selection for growth in shell height was conducted in a cultured population of the Japanese scallop Patinopecten yessoensis. Applying the same selection intensity ± 1.756 in upward and downward directions, three groups including two selected groups of Fast and Slow and one non-selected Control group were created, which were reared under the same environmental conditions at any stage. Differences always significantly existed among the three groups (P<0.05), except for larvae at day 1 and at day 5, and in the order of Fast>Control>Slow. The average standardized response to selection (SR), realized heritability (hR2) and genetic gain (GG) was 0.473%, 0.269% and 7.85% for the Fast group and 0.381%, 0.217% and 6.60% for the Slow group respectively. Moreover, significant differences (P<0.05) were detected between the fast and the slow lines in both SR and hR2, providing evidence for an asymmetric response in two directions. Performance in shell height is improved by 7.85% in the fast line after one generation selection, suggesting that mass selection for faster growth in a cultured population of the Japanese scallop is effective. [source] Nodavirus infection of juvenile white seabass, Atractoscion nobilis, cultured in southern California: first record of viral nervous necrosis (VNN) in North AmericaJOURNAL OF FISH DISEASES, Issue 5 2001P A Curtis The viral aetiology of mass mortalities of white seabass, Atractoscion nobilis, cultured in southern California, USA was examined. Disease outbreaks occurred in juvenile fish reared at two culture facilities from June to December 1999, with clinical signs such as anorexia and erratic swimming motion. Microscopic lesions observed in moribund fish included marked vacuolation of brain, spinal cord and retina. The piscine nodavirus (Betanodavirus), the causative agent of viral nervous necrosis (VNN), was detected in the affected tissues by electron microscopy, indirect fluorescent antibody test (IFAT), reverse transcription,polymerase chain reaction (RT,PCR), and isolation in cell culture. The agent was identified as one of the four known genotypes of piscine nodavirus. In addition, a similar nodavirus was also detected in fish samples from disease outbreaks at the same facility in 1992. In the last decade, VNN has been reported among cultured populations of marine fish worldwide and this paper is the first record of the agent in North America. [source] Gonadal Development and Differentiation in Cultured Juvenile Winter Flounder, Pseudopleuronectes americanusJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2007Elizabeth A. Fairchild Winter flounder, Pseudopleuronectes americanus, is currently being evaluated as a stock enhancement candidate in New Hampshire, USA; however, little is known about the gonadal development or the sex ratio of cultured juveniles. To determine the size at gonadal differentiation, 327 cultured fish ranging from <20 to 110 mm total length (TL), in 10-mm-TL size classes, were examined histologically. Gonads had differentiated into testes and ovaries in fish ,41 mm TL (98%), whereas the majority of fish (81%) smaller than 40 mm TL possessed undifferentiated gonads. A total of 313 cultured fish >40 mm TL were analyzed for sex ratio. In 2003, 67 females and 164 males were identified, yielding a sex ratio that was significantly skewed toward male (,2= 40.7, df = 1, P < 0.001). This trend held true when cultured fish were sorted by age and length, with the exception of those fish 61,70 mm TL. This aberration probably was because of a small sample size in this length category. However, in both the 2004 and the 2005 cultured populations, flounder sex did not deviate from a 1:1 ratio (2004 ,2= 0.12, df = 1, P= 0.724 and 2005 ,2= 0.02, df = 1, P= 0.881). The 2003 data suggest that environmental or genetic factors may affect winter flounder sex determination; rearing manipulation studies in the hatchery are needed to confirm this hypothesis. [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] | ||||||||||