水培经济植物净化养殖废水研究现状

对水培经济植物净化养殖废水的研究现状进行了阐述,介绍了湿地植物特别是水生经济植物相关情况,并指出：水培经济植物食用安全性是关键问题;西洋菜是用于处理养殖废水等高浓度有机废水的良好湿地植物。     

光滑河蓝蛤对净化养殖废水的净化效果

[目的]研究光滑河蓝蛤(Potamocorbula laevis)对大棚对虾养殖尾水的净化效果,确定净化废水时蓝蛤的养殖密度。[方法]设4个光滑河蓝蛤养殖密度处理,分别为0.5、1.0、2.0、3.0 ind/L,1个空白对照(CK),每组设置3次重复,养殖4 d,整个试验期间不换水,不投放饵料,测定不同处理对养殖废水中硝酸盐、氨氮(NH+4-N)、总磷(TP)、总氮(TN)的去除效果。[结果]光滑河蓝蛤4个养殖密度对NH+4-N、TP、硝酸盐均有显著的去除效果(P0.05),其中,1.0 ind/L处理净化效果最佳,对废水中硝酸盐的去除效率为62%±15.06%,NH+4-N的去除效率为48%±9.41%,TP去除率为99%±17.78%,TN的去除率为60%±3.74%。CK的净化效果最低,对废水中硝酸盐、NH+4-N、TP、TN的去除率分别为15%±3.36%、16%±0.58%、38%±6.86%、33±1.58%。[结论]光滑河蓝蛤的最佳养殖密度为1.0 ind/L。     

Measuring technical,allocative and cost efficiencies of seabass and seabream farms in Greece

Abstract

A stochastic Cobb‐Douglas production frontier is used to provide estimates of output‐oriented technical efficiency, input‐oriented technical efficiency, input allocative efficiency and cost efficiency for a sample of seabass and seabream farms in Greece. Mean output‐oriented technical efficiency is estimated at 78.5%, input‐oriented technical efficiency at 73.6%, input allocative efficiency at 79.2%, and cost efficiency at 58.2%. Considering the sources of efficiency differentials among fish farms, it is evidence from the empirical results that large farms tend to achieve higher (technical and allocative) efficiency scores; specialization in either seabass or seabream affects positively technical and cost, but not allocative, efficiency; and utilization of skilled labor seems to have a positive impact only on technical efficiency.     

Response of Bacterial Biofilms in Recirculating Aquaculture Systems to Various Sanitizers

ABSTRACT

Pathogenic microorganisms may be incorporated into biofilms found in aquaculture systems, causing recurring exposure to potential disease agents. Aerobic plate counts, the presence of Enterobacteriaceae, and the presence of Escherichia coli, modified to express a green fluorescent protein (GFP E. coli), was used to evaluate the effectiveness of various sanitizers in decreasing bacterial incorporation into newly generated biofilms in recirculating aquaculture systems. Disks of Buna-N rubber, polyvinyl chloride (PVC), chlorinated PVC, glass, fiberglass, and stainless steel were placed in aquariums stocked with Nile tilapia, Oreochromis niloticus. The effectiveness of water, an alkaline cleanser, sodium hypochlorite, a quaternary ammonium compound, or peracetic acid as a sanitizer was evaluated on each substrate by enumerating total plate counts, GFP E. coli, and Enterobacteriaceae. Sodium hypochlorite and peracetic acid were the most effective sanitizers, with an overall percentage reduction of GFP E. coli of approximately 2 logs₁₀. The quaternary ammonium compound was moderately effective, 1 log₁₀, against the target organisms. Water demonstrated a 2 log₁₀ reduction of the total plate count, suggesting that some mechanical cleaning was achieved. The type of material used as substrate for the biofilm had no significant (P?>?0.05) effect on the effectiveness of the sanitizers.     

Low-Salinity Acclimation of Juvenile Marine Goliath Grouper Epinephelus itajara

The ability of marine goliath grouper to survive in waters of low salinity was investigated by collecting juvenile individuals from the wild in full-strength seawater and either transferring them directly to fresh water or acclimating them over a 96-h period to fresh water. Juvenile goliath grouper (n = 49; mean 23.4 cm SL; SD 4.1; mean 339.1 g; SD 89.3) tolerated transfers from seawater (30 ppt) to freshwater (<1 ppt), and survived thereafter for a period of 28 d in strictly fresh water, with no observed adverse effects. However, the salinity tolerance was influenced by rate of exposure, as no deaths were observed when the fish were given a gradual decrease in salinity, but 60% of the individuals died when transferred abruptly from seawater into fresh water.     

Comanagement for aquaculture: Suggestions from a comparative study between two major production areas of milkfish in the Philippines

ABSTRACT

This study examined if, and how, comanagement is effective in controlling aquaculture industry in the municipalities of Anda and Bolinao in the province of Pangasinan, in the Philippines, the locations of two major production areas of milkfish (Chanos chanos) in the country. Institutional and community analyses conducted in these study sites revealed a unique hierarchy of resource users, as well as unique social and economic problems in aquaculture, distinct from those of capture fishery. It was also indicated that comanagement is seen as a solution for essential practices to be enforced practically and sustainably for the management of this industry. To improve aquaculture governance, it is desired that the comanagement scheme shall include not only the governments and fishers but also business operators who often have large capital and a high degree of power.     

Levels of domestication in fish: implications for the sustainable future of aquaculture

The agricultural world today is dominated by a few domesticated mammal species, that is, animals modified from their wild ancestors through selective breeding in captivity for traits beneficial to human usages. As a result, a clear dichotomy exists between wild (from hunting) and domesticated mammals (produced in farms) used for human consumption. Similar to agriculture, aquaculture is often viewed as the only solution that can provide more fish products given that harvesting wild stocks have reached an upper limit. Aquaculture is considerably younger than agriculture relying on natural sources to farm numerous species. To better describe the diverse strategies for fish production, we propose a new classification comprising five levels of ‘domestication’ with 1 being the least to 5 being the most domesticated. Our classification places 70% of the 250 farmed finfish species recorded in the 2009 FAO database into levels 1, 2 and 3 representing a transitory form of fish production dependent on the availability of the wild resource. In contrast, only a few species, or more accurately populations, can be considered truly domesticated, similar to cattle or sheep. Based on this classification, two scenarios for the future of aquaculture are discussed: either the industry focuses on few truly domesticated species, similar to the path taken by agriculture, but avoiding its negative impacts or aquaculture proceeds with inter‐specific diversification by focusing primarily on the domestication of native species.     

固定化藻菌去除淡水养殖废水氨氮效果及模型拟建

[目的]研究固定化藻菌去除水养殖废水氨氮效果及模型拟建.[方法]利用固定化藻菌(ABI)处理淡水养殖废水中的氨氮,采用多因子正交试验得到温度(T)、PH、光照强度(I)、溶解氧(DO)和填充率五因子与氨氮去除率(AR)之间的关系数据,拟建五因子与氨氮去除率关系模型.[结果]五因子对氨氮去除率均具有显著影响,最佳去氮氮组合为,温度30℃、pH值7.0、光照强度6 000 lx、溶解氧5.0 mg/L、填充率10%.根据实验数据拟建的方程模型决定系数R2=0.864 8,相伴概率P<0.05,对氨氮去除率的模型预测值与实际测值进行样本T-检验,结果表明总体均值差异显著值sig.为0.978(P>0.05),模型预测值与实际测值数据组无显著性差异,模型具有较高拟合度.[结论]为实现养殖废水中氨氮去除或浓度降低提供参考依据. Abstract： Applied Immobilized algae bacteria (ABI) to remove ammonia of freshwater aquaculture wastewater.Temperature (T),PH,light intensity (I),dissolved oxygen (DO) and filling rate five factors plays important role in the process of ammonia nitrogen removal,related data between ammonia removal and five factors was received through multi-factor orthogonal test,and established relations model between the five factor and nitrogen removal.The results show that five-factors had significant effect on AR,and the best combinations for removing AR was temperature 30 ℃,pH=7.0,light intensity 6 000 lux,dissolved oxygen 5.0 mg/L and the fill rate 10%.According to the experimental data,equation model was proposed and coefficient of determination R2=0.864 8,P<0O.05.Samples T-test was done between the model predictions and the actual measured values.Test results showed that the significant difference of overall mean value sig.(2-tailed) was 0.978 (P>0.05),it Shows that had no significant difference between model predictions and the actual measured value,and model had a high degree of fitting.     

基于面向“企业＋农户”模式的水产安全生产管理系统的研制——以珠海市为例

研究了面向＂企业＋农户＂模式的水产安全生产管理系统,提出了相应的建议,即促进水产企业与水产农户之间的合作与互动,发挥水产企业对农户水产养殖过程的监督和指导作用,促进水产安全生产,巩固和加强珠海斗门在水产业的地位,增加农民收入,改善珠海斗门水产品安全信息化建设状况。     

从多宝鱼事件探讨HACCP在水产养殖中的应用

分析了多宝鱼事件发生的原因,阐述了我国水产养殖中水产品质量安全控制面临的问题,并探讨了HACCP(危害分析与关键点控制)体系在水产养殖中的应用。