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Food Fish (food + fish)
Selected AbstractsPrimers from the orders Osteoglossiform and Siluriform detect polymorphic microsatellite loci in sun-catfish, Horabagrus brachysoma (Teleostei: Bagridae)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2006A. Gopalakrishnan Summary Horabagrus brachysoma (sun-catfish, Bagridae, Siluriformes) is a valuable ornamental and food fish. The stock structure of H. brachysoma, necessary to conserve its declining natural populations, is not known. Twenty-five primers developed for four fish species belonging to the orders Siluriform (3) and Osteoglossiform (1) were tested and eight primers amplified microsatellite loci in H. brachysoma. The results demonstrate that cross-priming between fish species belonging to different families and even to different orders can yield microsatellite loci. Five of eight primers each amplified two loci. However, the loci that had repeat motifs after sequencing were considered only for genotyping. Finally, eight loci were polymorphic with hree to seven alleles. Individual fish genotype data (n = 42; 21 each in two rivers) at each locus was analysed. Significant genetic heterogeneity was detected at six loci. The identified loci exhibited potential for use in population genetics application in H. brachysoma. [source] Iridovirus infections in finfish , critical review with emphasis on ranavirusesJOURNAL OF FISH DISEASES, Issue 2 2010R J Whittington Abstract Viruses in three genera of the family Iridoviridae (iridoviruses) affect finfish. Ranaviruses and megalocytiviruses are recently emerged pathogens. Both cause severe systemic disease, occur globally and affect a diversity of hosts. In contrast, lymphocystiviruses cause superficial lesions and rarely cause economic loss. The ranavirus epizootic haematopoietic necrosis virus (EHNV) from Australia was the first iridovirus to cause epizootic mortality in finfish. Like other ranaviruses, it lacks host specificity. A distinct but closely related virus, European catfish virus, occurs in finfish in Europe, while very similar ranaviruses occur in amphibians in Europe, Asia, Australia, North America and South America. These viruses can be distinguished from one another by conserved differences in the sequence of the major capsid protein gene, which informs policies of the World Organisation for Animal Health to minimize transboundary spread of these agents. However, limited epidemiological information and variations in disease expression create difficulties for design of sampling strategies for surveillance. There is still uncertainty surrounding the taxonomy of some putative ranaviruses such as Singapore grouper iridovirus and Santee-Cooper ranavirus, both of which cause serious disease in fish, and confusion continues with diseases caused by megalocytiviruses. In this review, aspects of the agents and diseases caused by ranaviruses are contrasted with those due to megalocytiviruses to promote accurate diagnosis and characterization of the agents responsible. Ranavirus epizootics in amphibians are also discussed because of possible links with finfish and common anthropogenic mechanisms of spread. The source of the global epizootic of disease caused by systemic iridoviruses in finfish and amphibians is uncertain, but three possibilities are discussed: trade in food fish, trade in ornamental fish, reptiles and amphibians and emergence from unknown reservoir hosts associated with environmental change. [source] Effects of Added Shelter and Stocking Density on Growth of Sleepy Cod Oxyeleotris lineolatus in PondsJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2003Brett W. Herbert Sleepy cod Oxyeleotris lineolatus is a species of freshwater goby in demand in Australian markets by consumers of Asian origin. It is related to marble goby Oxyeleotris marmoratus, the most expensive freshwater food fish in Asia, which is cultured throughout southeast Asia in ponds and cages. The performance of sleepy cod in culture conditions was investigated to assess the viability of farming them in northern Australia. Sleepy cod fingerlings (62.8 ± 0.8 mm total length and 2.56 ± 0.095 g) were stocked into experimental ponds at 32,857 fish/ha, and grown out for 8 mo. Shelter was provided in each of three replicate ponds and was absent in three control ponds. The provision of shelter in juvenile growout was found to be of no benefit, although fish in ponds provided with shelter weighed slightly more per unit length than fish in ponds without shelter. Cannibalism was not a problem in growout, and survival was close to 100%. After the shelter trial was completed, fish were graded into large and small classes (three replicates of each), and grown out without shelter at the same density for 158 d. Following that, fish were again graded, and the largest 30% retained from growout at a density of 8,857 fish/ha (large, 198 ± 6.44 g) or 10,000 fish/ha (small, 48.9 ± 1.27 g). These were grown out for 188 d. Growth of selected stock at low densities was slower than earlier growth rates, although smaller fish gained weight more rapidly than larger fish. Growth rates were better than the only published data for marble goby. Further investigation into high density culture and different genotypes of sleepy cod needs to be undertaken to determine the viability of pond culture. [source] Weaning Chinese perch Siniperca chuatsi (Basilewsky) onto artificial diets based upon its specific sensory modality in feedingAQUACULTURE RESEARCH, Issue 2001X F Liang Abstract Chinese perch are one of the most valuable food fish in China, but the sole source of feed for intensive culture is live prey fish. Our previous studies on systematic sensory physiology revealed that this species have a mechanism for this peculiar feeding habit. In the present study, a specific training procedure was designed, and both experimental (initial body weight 171.0 g; 120 days) and commercial (initial body weight 52.4 g; 240 days) net-cage cultures were conducted to investigate the training success, growth performance and survival of the trained yearlings fed with nonlive or Oregon-type moist diet. The training successes of minced prey fish and the Oregon moist diet were 100 and 89.9%, respectively, in experimental culture, and 92.2 and 83.5% in commercial culture. In an experimental trial, the fish fed minced prey fish or the Oregon moist diet attained final body weights of 472.7 g or 344.7 g, although the specific growth rates of these groups were significantly lower than that of the fish fed live prey fish (final body weight 560.0 g). Mortality was not significantly related to dietary treatment. In commercial culture, the final body weights were as follows: 750 g on live prey fish, 705 g on minced prey fish and 651 g on the Oregon moist diet. Feed costs to produce 1 kg fish were estimated to be US$6.59 for live prey fish, US$1.76 for minced prey fish and US$2.07 for the Oregon moist diet. The results of the present study confirmed that sensory modality and associative learning appear to be critical factors in determining food discrimination of Chinese perch, indicating that both minced trash fish and Oregon-type moist diet can be substituted for live prey fish in intensive commercial production. [source] The effects of introduced tilapias on native biodiversityAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2005Gabrielle C. Canonico Abstract 1.The common name ,tilapia' refers to a group of tropical freshwater fish in the family Cichlidae (Oreochromis, Tilapia, and Sarotherodon spp.) that are indigenous to Africa and the southwestern Middle East. Since the 1930s, tilapias have been intentionally dispersed worldwide for the biological control of aquatic weeds and insects, as baitfish for certain capture fisheries, for aquaria, and as a food fish. They have most recently been promoted as an important source of protein that could provide food security for developing countries without the environmental problems associated with terrestrial agriculture. In addition, market demand for tilapia in developed countries such as the United States is growing rapidly. 2.Tilapias are well-suited to aquaculture because they are highly prolific and tolerant to a range of environmental conditions. They have come to be known as the ,aquatic chicken' because of their potential as an affordable, high-yield source of protein that can be easily raised in a range of environments , from subsistence or ,backyard' units to intensive fish hatcheries. In some countries, particularly in Asia, nearly all of the introduced tilapias produced are consumed domestically; tilapias have contributed to basic food security for such societies. 3.This review indicates that tilapia species are highly invasive and exist under feral conditions in every nation in which they have been cultured or introduced. Thus, the authors have concluded that, despite potential or observed benefits to human society, tilapia aquaculture and open-water introductions cannot continue unchecked without further exacerbating damage to native fish species and biodiversity. Recommendations include restricting tilapia culture to carefully managed, contained ponds, although exclusion is preferred when it is feasible. Research into culture of indigenous species is also recommended. Copyright © 2005 John Wiley & Sons, Ltd. [source] Shrinking baseline: the growth in juvenile fisheries, with the Hong Kong grouper fishery as a case studyFISH AND FISHERIES, Issue 4 2009Allen W L To Abstract Historic and current information on the grouper fishery from Hong Kong and adjacent waters reveals significant changes in species composition and fish sizes over the past 50 years in this important Asian centre for seafood consumption. Once dominant, large groupers are now rare and small species and sizes prevail in the present-day fishery. Juveniles comprise over 80% of marketed fish by number among the most commonly retailed groupers, and reproductive-sized fish are absent among larger species. Current fishery practices and the lack of management in Hong Kong and adjacent waters pose a significant threat to large species with limited geographic distribution such as Epinephelus akaara and Epinephelus bruneus, both now listed as threatened by the IUCN. The heavy reliance on juveniles, not only for groupers, but for an increasing diversity of desired fishes within Asia, potentially reduces stock spawning potential. The ,shrinking baseline' in terms of a progressive reduction in fish sizes being marketed in the region can seriously undermine fishery sustainability and recoverability of depleted fish stocks. Fishing pressure on groupers and other valuable food fishes within the Asia-Pacific is intensifying, the declining long-term trend of grouper landings in Hong Kong and the increasing focus on juveniles for immediate sale or for mariculture ,grow-out' signal a worrying direction for regional fisheries. Moreover, the common appearance of small groupers for sale will influence public perception regarding what are ,normal-sized' fish. Management attention is needed if these fisheries are to remain viable. [source] | ||||||||||