围塘混合养殖环境中重金属在水、生物体和底泥间的富集分布   总被引：1，自引：0，他引：1  

江锦花  祝力飞  谢正 《海洋水产研究》2006,27(1):71-75

研究了椒江口围塘混合养殖环境中重金属在水、生物体和底泥间的富集分布,以及该环境中重金属在鲈鱼、鲻鱼、鲶鱼3种鱼样各组织中的分布积累情况。结果表明,与其他海域相比,围塘养殖水体和沉积物中重金属铜的平均含量偏高;3种鱼样中铜的积累规律相同的是皮>鳍>肌肉,镉、锌、铅在鱼体中的相同积累规律是鳍>皮>肉,不同鱼体各组织中重金属的含量为鲻鱼>鲶鱼>鲈鱼,鱼样各组织中重金属的分布积累具有显著性差异。  相似文献   

Tench (Tinca tinca) broodstock management in breeding station under conditions of pond culture: a review     

DAVID GELA  MARTIN FLAJŠHANS  MARTIN KOCOUR  MAREK RODINA  OTOMAR LINHART 《Aquaculture International》2006,14(1-2):195-203

A basic assumption for carrying out the breeding work is to have well-organised broodstock management. Taking into account the number of populations bred and the limited number of ponds available, it is impossible to avoid rearing several juvenile or adult breeds in mixed stocks. Fish of individual breeds are group-marked with regular renewal of the freeze-branded mark and broodstock adults should be marked individually. To minimise inbreeding or losses in genetic variation, at least 120 fish per strain are reared and when the strain is restored, factorial crosses of at least 15 females and 25 males should be applied. All activities are individually registered in the “Evidence 2003” data-recording software and data can be sorted by the origin of the fish population, of the strain or of individual fish; reproductive and performance parameters are recorded individually also. Further breeding operations with tench comprise the selection after over-wintering and rearing of fish before, during and after the reproductive season.  相似文献   

Impacts of otter (Lutra lutra L.) predation on fishponds: A study of fish remains at ponds in the Czech Republic     

Zdeněk Adámek  David Kortan  Pavel Lepič  Jaroslav Andreji 《Aquaculture International》2003,11(4):389-396

The increasing numbers of otters (Lutralutra L.), which are protected by the CzechAct of Nature and Landscape Protection, arecausing serious problems for fishpondmanagement. The diet of otters on pond farmsconsists predominantly (80%) of common carp,Cyprinus carpio, and to a lesser extentother pond fish species (perch, Percafluviatilis, zander, Stizostedionlucioperca and grass carp, Ctenopharyngodon idella). The size of carpcaptured by otters ranged between 376–683 mmTL (500 ± 88 mm) and 1,049–11,768 g(3,478 ± 2,867 g). Reconstructed originalweight and length of captured grass carp andperch were 599 and 182 mm TL, and 2,665 and163 g, respectively. In most of prey fishcorpses left by otters, only viscera andassociated parts were consumed. The weight ofindividual common carp corpses was estimated as73.0 ± 24.6 (26.3–95.9)% of theoriginal reconstructed weight, which means thatonly 27.0 ± 17.2 (4.1–73.7)% of fishbody mass was consumed by otters. In perch,62.8% of fish body mass was left unconsumed.Heavy losses have been reported also on fishstocks in ice-covered ponds during the winterperiod, when shoals of resting fish have beendisturbed and stressed due to otter hunting.  相似文献   

Investigation on fecundity, follicles and free embryo size of pond-reared pike (Esox lucius) of different age and size     

Tania Hubenova  Angel Zaikov  Penka Vasileva 《Aquaculture International》2007,15(3-4):235-240

The purpose of the present study is to investigate the gonadosomatic index (GSI %), the absolute and relative fecundity of one-year-old pike weighing over 400 g and at the same time to study the dependence between the egg size and the size, behavior and vitality of the free embryos obtained from one- and two-year-old spawners. The study involved two weight groups of females, differing in age and body weight and length—one-year-old (W = 514 g, SL = 36.1 cm) and two-year-old matured pike (W = 1454 g, SL = 49.3 cm). Ovary samples were fixed and egg follicles containing maturing oocytes counted and weight. The weight and length of the free embryos from semi-artificial spawning were measured. The results showed that, when raising this species under farmed conditions, more than 40% (in rarer cases 90%) of one-year-old pike females reached over 400 g and 35 cm (SL) and reached puberty. Absolute fecundity of 15,030 follicles (30 follicles per gram body weight) was observed; the GSI was nearly 15% and the follicle weight reached 3.7 mg. This data differs significantly from that obtained from the larger two-year-old fishes: absolute fecundity 41,363 follicles (28 follicles per gram body weight), GSI nearly 20%, follicle weight 5.8 mg. Results showed that the different follicle size determines the free-embryo size. A positive linear correlation was found between the egg follicle weight and the free-embryos weight (r = 0.7143). The free embryos obtain from the one- and two-year-old spawners differed significantly both in terms of their weight (7.13 mg against 10.61 mg) and total length (0.81 cm against 0.97 cm), the differences being 1.5- and 1.2-fold, respectively.  相似文献   

洛阳市河滩池塘养鱼万亩高产技术的研究     

白遗胜 《水产学报》1996,20(4):319-324

将我国传统养鱼与现代技术相结合，创造了传统式，集约化和半集约化三种养殖方式共存，融合，变通和转换的格局。应用微机进行动态分析计算，８１２．６公顷河滩池塘，平均每公顷鱼产量提高到１００３５ｋｇ和２００８５元经济效益，分别比原来增加１０５．５％和７０．２％，总体效益十分显著。此外，还探讨了高产的理论问题。  相似文献   

水质改良机改善池塘水质的初步研究   总被引：4，自引：0，他引：4       下载免费PDF全文

殷肇君 《水产学报》1997,21(3):322-326

通过多年的研究和生产实践证明，在利用水质改良机改良池塘水质时，应走机械与生物相结合的道路，中文提出翻喷池塘淤泥是改良池塘水质的最有效途径之一，既能充分利用浮游生物光合作用所释放的大量氧，又能有效偿还氧债，改良水质，从而达到提高鱼产量和节能的目的。本文强调偿还养殖水体的氧债，对改良池塘水质至关重要。  相似文献   

Modeling industry-wide sediment oxygen demand and estimation of the contribution of sediment to total respiration in commercial channel catfish ponds     

James A. Steeby  John A. Hargreaves  Craig S. Tucker  Thomas P. Cathcart 《Aquacultural Engineering》2004,31(3-4):247-262

Data collected from 45 commercial channel catfish, Ictalurus punctatus, ponds were used to develop empirical models predicting sediment oxygen demand (SOD). Seven acceptable models were combined with a Monte-Carlo sampling distribution to predict industry-wide sediment oxygen demand (SOD_i). The SOD_i values obtained from the best equation were used in simulations to assess the effect of diurnally varying water column dissolved oxygen (DO) concentrations on SOD and the effect of pond water depth on the contribution of SOD to overall pond respiration. Estimated SOD_i ranged from 62 to 962 mg m⁻² h⁻¹, with a mean of 478 mg m⁻² h⁻¹. There was a 95% probability of mean SOD_i being ≥700 mg m⁻² h⁻¹. The effects of diurnal variation in DO concentration in the water column on expression of SOD was modeled by combining maximum SOD_i, an empirical relationship between DO and SOD, and simulated pond DO concentrations. At DO concentrations >15 mg l⁻¹, diel SOD in catfish ponds exceeded 20 g O₂ m⁻² day⁻¹. But when average diel DO was <4 mg l⁻¹ and the range of DO concentration was 6–8 mg l⁻¹, SOD decreased to 13 g O₂ m⁻² day⁻¹ because DO availability limited the full expression of potential SOD. Respiration totals for sediment (average SOD_i), plankton, and fish respiration were calculated for pond water depths ranging from 0.25 to 4 m. Although whole-pond respiration increases as pond depth increases, the proportion of total respiration represented by sediment decreased from 48 to 10% by increasing water depth over this range. The results of these studies show that SOD is a major component of total pond respiration and that certain management practices can affect the impact of SOD on pond oxygen budgets. Mixing ponds during daylight hours, either mechanically or by orienting ponds for maximum wind fetch, will increase oxygen supply to sediments, thereby allowing maximum expression of SOD and maximum mineralization of sediment organic matter. Given a mixed condition caused by wind or other artificial means, the construction of deeper ponds increases the total mass of DO available for all respiration, causing nighttime DO concentrations to decline at a slower rate, reducing the need for supplemental aeration. Because a pond’s water volume decreases over time from sediment accumulation, annual aeration costs will increase with pond age. Constructing ponds with greater initial depth will therefore reduce long-term cost of aeration, allow more flexible management of pond water budget, and reduce the long-term expense associated with pond reconstruction.  相似文献   

Altered drying regime controls distribution of endangered salamanders and introduced predators     

Timothy J. Maret  Jonathan D. Snyder 《Biological conservation》2006,127(2):129-138

Introduction of invasive species has been implicated in the decline of many native species. However, the mechanisms that underlie successful invasion and species replacement are often poorly understood. We tested the hypothesis that disruption of the natural disturbance regime can facilitate invasion of habitats, resulting in the exclusion of native species. In Arizona’s San Rafael Valley, cattle ponds designed to hold water year-round have replaced seasonal marshes, and this altered drying regime has facilitated invasion by disturbance-intolerant fish and bullfrogs that negatively affect native Sonoran tiger salamanders. We investigated the relationships among pond drying regime, presence of introduced fish and bullfrogs, and presence of tiger salamander populations in 42 ponds. Both fish and breeding bullfrog populations disappeared following pond drying. Pond drying in cattle ponds negatively affected salamanders, but not to the same extent that it affected fish and bullfrogs. Metamorphosed bullfrogs ate salamander larvae in laboratory and field experiments, and the risk of local extinction among salamander populations was increased by introduced fish. Once fish eliminated salamanders from an aquatic habitat, salamanders seldom reappeared unless fish were killed by drying. Simple models were developed to predict change in salamander, fish, and bullfrog distributions with changes in cattle pond drying frequency. The models show that decreases in pond drying frequency could negatively affect salamanders by leading to a community dominated by disturbance-intolerant fish and bullfrogs, but increased drying frequency could negatively affect salamander populations by preventing salamander breeding. These results suggest that manipulation or restoration of disturbance regimes may be a powerful tool in managing for native species threatened by biotic invasions.  相似文献   

西北地区池塘养鱼决策系统的研制     

魏帮龙  孙长莲 《农业网络信息》2004,(1):15-17

通过研究甘肃池塘养鱼的多种模式，确定了一整套切合甘肃实际的池塘养鱼新技术，在此基础上建立了池塘养鱼的决策系统。  相似文献   

嗜水气单胞菌对黑斑蛙和花背蟾蜍的致病性研究     

王宗焕  李英斌 《经济动物学报》1999,3(1):51-53

利用经分类鉴定并保存于固定培养基中的ＡＨ９８０４嗜水气单胞菌株对黑斑蛙和花背蟾蜍进行动物接种感染试验（腹腔接种剂量２ｍＬ、含菌数１４４×１０８个），结果显示，该菌对上述２种动物具有明显的致病作用。同时，使用所制备高免血清作了同种动物免疫保护试验（血清抗体效价１２８０、肌肉接种剂量３０ｍＬ），对其结果进行了验证。  相似文献