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在主养尼罗罗非鱼淡水池塘中混养鲈，利用鲈捕食罗非仔鱼及野杂鱼，控制池塘栽鱼密度，结果：３个试验池罗非鱼亩净产比对照池分别提高６７ｋｇ，８７ｋｇ和５１ｋｇ，饵料系数比对照池分别降低０．２，０．２５和０．０７，放养尾重２５～５０ｇ的２龄鲈种较为适宜，试验证实了鲈与罗非鱼在淡水鱼塘中混养的可行性及生态学上的意义。 相似文献
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中国对虾与海湾扇贝混养试验表明,混养池主要理化因子指标好于对照池,混养池对虾平均亩产和对虾产品规格也好于对照池,并兼得了亩产海湾扇贝202.3 kg的理想效果,试验取得了较好经济效益。 相似文献
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本试验研究改良了池塘水质环境，预防了疾病的发生和避免了虾蟹相残，使以虾为主的虾、蟹、藻混养试验池与对虾单养对照池的对虾成活率大体接近。试验塘和对照塘均养两造，试验塘年亩均综合产量222．05kg；亩均产值6085．13元，亩均盈利2472．61元。 相似文献
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在江苏省射阳县开展了中国对虾一年养成两茬试验；第一茬用塑料大棚培育越冬亲虾早繁苗；于4月下旬放养，7月底起捕；第二茬5月中旬开始，专池暂养虾苗，8月上旬放养，10月底之前起捕，两茬亩产对虾116.3kg，比对照池提高34.8kg；每亩经济效益1114.70元，比对照池增加492.40元。 相似文献
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对虾,青蟹,江蓠混养试验研究 总被引：2，自引：0，他引：2
本试验研究改良了池塘水质环境，预防了疾病的发生和避免了虾蟹相残，使以虾为主的虾、蟹、藻混养试验池与对虾单养对照池的对虾成活率大体接近，实现亩均综合产量２２２．０５ｋｇ，亩均产值６９８５．１３元，亩均盈利２４７２．６１元，是一种高产、优质、高效的多元化养殖模式。 相似文献
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Abstract The effects of perch, Perca fluviatilis L., and bronze bream, Abramis brama (L.), predation on the production of insects emerging at the water surface and the autumn biomass of benthic macro-invertebrates were assessed in a series of experimental ponds. The study attempted to discover whether fish affect food availability for diving and dabbling ducks in freshwater habitats. Ten ponds (bisected by fine netting) were used for the study: one was left totally fish-free, whilst one half of each of three groups of three ponds was stocked with either perch, bream or perch plus bream. The relative abundance of emerging insects (mainly Chironomidae) was significantly reduced in two perch ponds, two perch + bream ponds and two bream ponds. The autumn standing crops of benthic macroinvertebrates were significantly reduced in one perch pond, three bream ponds and one perch plus bream pond. These results support findings of a contemporaneous large bio-manipulation experiment carried out in two adjacent lakes. During the biomanipulation studies, aquatic invertebrate standing stocks greatly increased after the removal of fish and decreased following restocking. 相似文献
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Donald Wujtewicz Bernard R. Petrosky Dorene L. Petrosky 《Journal of the World Aquaculture Society》1997,28(3):249-259
Annual drawdown of crayfish culture ponds to plant forage crops also serves to eradicate most predaceous finfish. Without annual drawdown predaceous fish populations may reach numbers that can significantly reduce the crayfish crop. Frequent drawdown may not be feasible or desirable in some management schemes. Evidence in the literature suggests that differential toxicity of rotenone would allow removal of fish without harming crayfish in the same pond. In the current study, laboratory and in situ acute toxicity bioassays (96 h) were conducted with 5% non-synergized emulsifiable rotenone to define the maximum non-lethal concentration (LC100 ) for white river crayfish Procambarus acutus acutus and the minimum lethal concentration (LC100 ) for white perch Morone americana . Six concentration levels of rotenone formulation were tested in each of six toxicity trials with crayfish using dechlorinated tap water at 21–25 C. LC0 (compensated for control mortality) was determined to be 3.0 mg/L. Significant crayfish mortality began at 4.0 mg/L. Acute toxicity to white perch was anticipated to be within recommended concentration levels on product label for similar fish, and was corroborated by laboratory bioassay (LC100 of 0.15 mg/L). Both species were then tested together in laboratory aquaria utilizing pond water at room temperature. Concentration levels of 0.05–2.5 mg/L killed all white perch with no crayfish mortality. In the final phase of the study a 1.0 mg/L concentration of rotenone was applied to a pond containing both species held in cages. All white perch were dead within 24 h; no crayfish mortality was observed for the 96-h duration of the trial. It may therefore be possible to use this rotenone formulation to control white perch and other finfish in active crayfish culture ponds. 相似文献
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L. Heermann L.-O. Eriksson C. Magnhagen J. Borcherding 《Ecology of Freshwater Fish》2009,18(4):560-571
Abstract – Size is a crucial factor affecting the survival of fish during winter. Pond and laboratory experiments with three size classes of perch (small: 40–70 mm, medium: 71–100 mm, large: 101–186 mm) revealed that the feeding history of perch prior to winter is reflected in the amount and type of accumulated energy reserves. The minimal amount of reserves was 2% of the perch's biomass for fat and 9% for protein. An increase in glycogen levels either reflected mobilisation of energy in the body when perch were starving or an increase in accumulated energy over winter. In the laboratory, only the smallest perch suffered from high mortality rates, even if all were fed with low amounts of food. However, feeding the fish reduced the mortality rate after a certain time lag. Size-selective mortality rates occurred in the pond experiments as well. Small perch which survived the winter were able to rebuild their energy stores. 相似文献
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提高鲈鱼苗池塘培育成活率试验 总被引：2，自引：0，他引：2
捕捞天然鲈鱼进入养殖的哲养阶段死亡率较高,如何提高暂养成活率？在５．１亩池塘内进行了试验。主要措施：施鸡粪,磷肥,尿素肥水,调节水质和透明度,选用软质尼龙材料捕苗,装苗,带水妥苗,放养鲈鱼规格整齐,及时调整投饵量,结果：经６２天培育,成活率达７１．４％,亩纯利３３７２５元,试验认为,放养密度以２万尾／亩为宜。 相似文献
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Abstract. Salmonid fish at fish farms in northern and central Finland and perch, Perca fluviatilis L., roach, Rutilus rutilus (L.), and whitefish, Coregonus sp., from four lakes in central Finland were studied between 1985 and 1990 for the occurrence of Yersinia ruckeri. The bacteria were found in fish from both areas, but in most cases, only single diseased salmon, Salmo salar L., brown trout, S. trutta L., rainbow trout, Oncorhynchus mykiss (Walbaum), whitefish and perch were encountered and were always connected with stress conditions. One clinical outbreak occured in salmon fingerlings in northern Finland, and the fish were successfully treated with trimethoprim-sulpha. Monthly monitoring of lake fish revealed two symptomless carrier perch in two lakes. Outwith the main study a moribund perch with yersiniosis was found in a polluted lake, and for the first time in Finland, a rainbow trout was also found to have contracted yersiniosis in a small private pond. Sorbitol-positive and negative isolates have been found to occur in both moribund and carrier farmed fish, indicating that the sorbitol test is not essential when evaluating the pathogenicity of Y. ruckeri. 相似文献
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Growth and survival of 0+ perch were studied in 4 ponds with the topmouth gudgeon (Pseudorasbora parva) and without it. In the end of April, all ponds were stocked by free-swimming perch larvae (120,000 ind ha?1). In June, topmouth gudgeon was introduced as forage fish (40 kg ha?1) into two of the experimental ponds. Topmouth gudgeon significantly influenced neither the total abundance of zooplankton nor the abundance of its groups (Rotifera, Cladocera, Copepoda). The most important food item for perch (TL > 29 mm) was macroinvertebrates (especially Chironomidae). In the ponds with topmouth gudgeon, copepods and cladocerans were more important than in ponds without it. Specific growth rate of perch was 0.01 mm day?1 in all ponds. Final mean total length (TL ± SD) of perch was 73 ± 13 and 70 ± 6 mm in the ponds with topmouth gudgeon and without it, respectively. Only 1 % of the perch reached higher TL than that recorded in the ponds without the topmouth gudgeon. Survival rate of perch varied from 12 to 36 % depending on ponds. Piscivory was recorded in all ponds from the age of 57 days (post-stocking); however, perch siblings were preferred to topmouth gudgeon. The highest asymptotic growth (L∞ = 88 mm) was calculated in the pond stocked with topmouth gudgeon. This corresponded with the highest cannibalism and lowest survival rate (12 %). Perch growth rate increased till 42–53 days of perch age and then started to decrease. There was no significant influence of potential prey fish (topmouth gudgeon) on the growth of 0+ perch; however, two size cohorts were found in the ponds with the topmouth gudgeon. Presence or absence of littoral macrophytes seems to be more substantial for rearing perch in ponds than stocking with the prey fish. 相似文献
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Stuart J. Rowland 《Journal of the World Aquaculture Society》2009,40(3):291-324
Silver perch, Bidyanus bidyanus (Mitchell), is a freshwater fish that is endemic to the Murray‐Darling River System, Australia. Over recent decades, its distribution and abundance in the wild have declined, and it is now a threatened species with the conservation status of “vulnerable.” Silver perch is a schooling, omnivorous fish, with white flesh, few bones, and high levels of omega fatty acids, and its aquaculture potential has long been recognized. Hatchery techniques, based on hormone‐induced spawning of captive broodfish in tanks and rearing of larvae in fertilized earthen ponds, were developed in the early 1980s. Fingerlings are currently used for stock enhancement and conservation or sold for commercial grow‐out or stocking farm dams. Research into the grow‐out of silver perch commenced in 1990 and demonstrated that it is an excellent fish for culture in static aerated earthen ponds with high survival rates (>90%), fast growth rates (2–5 g/fish/d) at high stocking densities (20,000/ha) leading to high production rates (10 tonnes/ha/yr). Since 1996, there has been research into nutrition, diet development, feeding strategies, broodfish domestication and management, culture in tanks and tank‐based recirculating aquaculture systems, diseases, health management, genetic improvement, and cage culture. Silver perch is a hardy species that performs well under different culture conditions and on diets with no or low levels of fish meal. Technology has been transferred to industry through major conferences in 1994 and 2003 as well as workshops, field days, extension, seminars, and numerous scientific and technical publications. The high quality of silver perch and its excellent culture attributes suggest that the species has the potential to form a large industry based on high‐volume, low‐cost production. However, despite these features and a strong technical base provided by research and development, industry growth has been limited and a relatively small industry currently produces only around 500 tonnes annually. Development has been restricted by a number of factors: poor site selection and design of some farms; use of inappropriate husbandry and/or production strategies; difficulties with pond production, including significant losses to bird predation and diseases; high costs of feeds; limited marketing and promotion; no processing component; no large‐scale investment; and the failure of many farms that were too small to be economically viable. Recent research has found that silver perch performs well in cages (high survival [>90%], good growth [1.7–3.5 g/fish/d], and high production rates [50–90 kg/m3]), and cage culture has advantages such as ease of management and prevention of bird predation that may help overcome some of the problems associated with pond production. Improved health management, new production strategies, cage culture, use of interstrain hybrids and other genetically improved fish, and integration with cotton and other irrigation industries offer opportunities for increased production and efficiencies, and further development of the silver perch industry. The potential of silver perch for commercial aquaculture remains very high. 相似文献