大珠母贝人工苗水泥池中间培育技术的初步研究

为了解决大珠母贝幼贝海区养殖大规模死亡问题，开展了贝苗水池中间培育技术研究。本实验共用3批人工繁殖的2～3mm贝苗，经6个月的水泥池（335m^2）养殖，平均壳长分别增长至35．8mm、27．7mm、23．4mm，平均壳高分别增长至30．1mm、24．9mm、20．1mm，成活率分别为29．5％、17．4％、17．9％。该试验表明，大珠母贝种苗池塘中间培育生长速度快，成活率高，有望克服海区养殖大规模死亡问题。     

Grow-out of sandfish Holothuria scabra in ponds shows that co-culture with shrimp Litopenaeus stylirostris is not viable

We examined the potential for producing the large numbers of sandfish (Holothuria scabra) needed for restocking programmes by co-culturing juveniles with the shrimp Litopenaeus stylirostris in earthen ponds. Our experiments in hapas within shrimp ponds were designed to detect any deleterious effects of sandfish on shrimp, and vice versa. These experiments showed that a high stocking density of juvenile sandfish had no significant effects on growth and survival of shrimp. However, survival and growth of sandfish reared with shrimp for 3 weeks were significantly lower than for sandfish reared alone. Increased stocking density of shrimp also had a significant negative effect on survival and/or growth of sandfish. A grow-out trial of juvenile sandfish in 0.2-ha earthen ponds stocked with 20 shrimp post-larvae m^− 2, and densities of sandfish between 0.8 and 1.6 individuals m^− 2, confirmed that co-culture is not viable. All sandfish reared in co-culture were dead or moribund after a month. However, sandfish stocked alone into 0.2-ha earthen ponds survived well and grew to mean weights of ∼ 400 g within 12 months without addition of food. The grow-out trial demonstrated that there is potential for profitable pond farming of sandfish in monoculture. Further research is now needed to identify the optimal size of juveniles, stocking densities and pond management regimes.     

Seasonal dynamics of fish assemblage in a pond canal

The annual dynamics of fish assemblage in a pond-connecting canal of a South Moravian pond aquaculture facility was studied to reveal potential assemblage effects on pond stocks and vice versa. The species richness of fish assemblage and seasonal dynamics of its development were predominantly dependent upon the fish stock of the interconnected ponds (particularly due to escapees during the period of pond harvesting), which contributed to a considerable increase of commercial fish species occurrence. Using a seasonal parameter, the season proved to have a major impact on fish assemblage dynamics (r = −0.71, P < 0.001). Spring samples were dominated by commercial fishes of aquaculture origin (mainly Cyprinus carpio). Occurrence of several fish species originating from the wild (bleak, Alburnus alburnus, chub, Leuciscus cephalus and roach, Rutilus rutilus) was also reported. The pond canal was found to be an important reservoir site of persistent survival and potential subsequent spreading of some undesirable alien fishes such as topmouth gudgeon (Pseudorasbora parva) and gibel carp (Carrasius auratus). Moreover, more attention should be paid to the potential negative impacts of all fishes of aquaculture origin upon the natural ecosystem and to the adverse effects due to the immigration of wild fish into aquaculture pond farming units.     

盐碱地鱼池水化学因子与浮游植物的调查研究

对山东黄河两岸和河口地区盐碱地鱼池的水化学因子与浮游植物进行了调查研究，确认鱼池水型属ＣｌⅢ＾Ｎａ，ＣｌⅡ＾Ｎａ和ＣｌⅠ＾Ｎａ型的氯化水，ｐＨ变化在７．６－８．９之间，盐度在０．９－８之间，营养盐含量比一般淡水鱼池低，浮植物甚至不如小型水库，湖泊丰富。     

Incorporation of Maize Gluten in Supplementary Feed and its Impact on Growth and Flesh Quality of Some Carps

Maize gluten (a byproduct from the starch industry) was used at four different levels (5, 10, 15 and 20% w/w) replacing the fish meal, a component of supplementary diet, under a semi-intensive culture system. The impact of different diets on the physico-chemical parameters of water, growth and flesh quality of catla, Catla catla; rohu, Labeo rohita; and mrigal, Cirrhina mrigala was studied. Growth in terms of body weight gain was highest when fed a diet having 5% maize gluten (replacing fish meal at 25% level) for all the fish species. However, incorporation of maize gluten at higher levels led to decline in growth, since maize gluten is deficient in essential amino acids like methionine, lysine and threonine, etc. The flesh quality in terms of total protein, total lipid, total sugar, moisture and total ash was also determined at the termination of the experiment to see whether there was any significant variation with the incorporation of maize gluten or not.     

“Summer syndrome” in Litopenaeus stylirostris grow out ponds in New Caledonia: Zootechnical and environmental factors

The “Summer Syndrome”, a septicemic vibriosis caused by Vibrio nigripulchritudo, is responsible for one of the two main seasonal mortalities which affect shrimp aquaculture in New Caledonia. It was identified for the first time in December 1997 in an intensive shrimp farm (called farm DF) and has been enzootic ever since. The “Summer syndrome” affects shrimp during warm-season growout. Although the geographic area concerned is limited, it is a potential threat for the industry in that the disease could spread. Analysis of grow out data from 1991 to 2002 in this farm was carried out in order to characterize the disease and the environmental conditions in relation to mortality. Results of farm DF were compared to data from farms not affected by the disease (called farms HC). The “Summer syndrome” occurs during the warm season which is characterized by an increase in water temperature and sunny duration. This disease is characterized by simultaneously highest densities and weakest drying duration between crops in the farms studied. Between 1991 and 2002, the increase of feed input and nitrogen rate in feed has led to a significant increase of the growth rate over the years in farm DF. At the same time, water management has not changed and has induced an increase in environmental waste production. In consequence, an early eutrophication of water is observed, which is concomitant with the beginning of the mortality outbreaks. This could play a role by inducing directly or indirectly a stress for shrimp and/or a growth and/or virulence factors of the pathogen.     

Photosynthetic suspended-growth systems in aquaculture

Standardized evaluation and rating of biofilters for aquaculture should be assessed in the context of the economic efficiency of ecological services (waste assimilation, nutrient recycling, and internal food production) provided by earthen ponds, and the availability and cost of land, water, and electrical energy resources required to support particular classes of production systems. In photosynthetic suspended-growth systems, water quality control is achieved by a combination of natural and mechanical processes. Natural processes include photosynthesis of oxygen, algal nutrient uptake, coupled nitrification–denitrification, and organic matter oxidation; mechanical processes include aeration and water circulation. Ammonia is controlled by a combination of phytoplankton uptake, nitrification, and immobilization by bacteria. Unlike biofilters for recirculating aquaculture systems, unit processes are combined and are an integral part of the culture unit. The important design and operational considerations for photosynthetic suspended-growth systems include temperature effects, aeration and mixing, quantity and quality of loaded organic matter, and fish water quality tolerance limits. The principle advantages of photosynthetic suspended-growth systems are lower capital costs relative to other recirculating aquaculture systems and increased control over stock management relative to conventional static ponds. The main disadvantage is the relatively low degree of control over water quality and phytoplankton density, metabolism, and community composition relative to other recirculating aquaculture systems. Examples of photosynthetic suspended-growth systems include semi-intensive ponds, intensively aerated outdoor lined ponds, combined intensive–extensive ponds, partitioned aquaculture systems, greenwater tanks, greenwater tanks with solids removal, and greenwater recirculating aquaculture systems.     

宁夏银川地区池塘养殖河蟹技术探讨

从池塘修建、河蟹放养规格、时间、密度、生产管理和疾病防治等方面探讨了宁夏银川地区池塘养殖河蟹技术,试验养殖的河蟹产量达6 393.0 kg/hm2、平均135.3 g/只,经济效益达18 840元/hm2,具有较好的开发前景。     

卡拉白鱼人工繁育及池塘养殖试验研究

[目的]探讨卡拉白鱼在辽宁地区的人工繁殖、苗种培育和池塘养殖技术.[方法] 2012年开始在辽宁省铁岭养殖基地进行卡拉白鱼人工繁育及池塘养殖试验.[结果]引进卡拉白鱼种鱼400对,催产后人工繁殖的仔鱼经过110 d培育后平均体长达6.65 cm,平均体质量达3.10g;春片经过135 d培育后平均体长达到14.50 cm,平均体质量达到28.50 g.在0.18 hm2池塘投入3龄苗种1.0万尾,经过132 d培育后平均体长达23.80 cm,平均体质量达123.90 g,出塘商品鱼的产量为6 600 kg/hm2,出塘率为96.0％,饵料系数1.8.特定生长率（SGR）和日增重（AWG）在6～8月较高,主要是因为适宜的水温、水质环境和合理的投饲方法,3龄即可达到100 g以上的食用标准.[结论]卡拉白鱼在6～8月生长较快.     

黄河故道河蟹生态养殖

从清塘、种草投螺、施肥、蟹种投放、水质管理、饲养管理和合理混养等方面对河蟹的生态养殖技术进行了探讨。