池塘循环水生态养殖效果分析

用多种生物修复技术结合池塘工程改造手段,构建封闭型池塘循环水生态养殖系统。养殖水体的水质指标监测结果表明,该循环系统对TN、TP、NH4+-N及CODMn的平均去除率分别达62.89%、60.24%、56.52%、47.81%,具有很好的净化效果,能够满足养殖用水的要求,在整个养殖过程中实现了养殖尾水零排放。该循环水养殖模式符合当前太湖保护的规划要求。     

Host response to the chondracanthid copepod Chondracanthus goldsmidi,a gill parasite of the striped trumpeter,Latris lineata (Forster), in Tasmania

The chondracanthid copepod, Chondracanthus goldsmidi is an ectoparasite of gills, inner opercula and nasal cavities of cultured striped trumpeter, Latris lineata (Forster). Whilst often present in high numbers (up to 60 parasites per host), little is known about its effect on striped trumpeter. In this study C. goldsmidi was associated with extensive epithelial hyperplasia and necrosis. Pathological changes were most pronounced near the parasite’s attachment site, with papilloma‐like growths surrounding the entire parasite resulting in deformation of the filament. The number of mucous cells increased near the parasite attachment sites on both the opercula and gills. Mast cells were absent in healthy gills; in contrast numerous mast cells were identified in the papilloma‐like growths. Immunostaining identified piscidin‐positive mast cells in the papilloma‐like growths, presenting the first evidence of piscidin in the family Latridae.     

Gleaner,fisher, trader,processor: understanding gendered employment in fisheries and aquaculture

Most research on gender difference or inequities in capture fisheries and aquaculture in Africa and the Asia‐Pacific focuses on the gender division of labour. Emerging research on globalization, market changes, poverty and trends in gendered employment within this sector reveals the need to move beyond this narrow perspective. If gleaning and post‐harvesting activities were enumerated, the fisheries and aquaculture sector might well turn out to be female sphere. A livelihoods approach better enables an understanding of how employment in this sector is embedded in other social, cultural, economic, political and ecological structures and processes that shape gender inequities and how these might be reduced. We focus on four thematic areas – markets and migration, capabilities and well‐being, networks and identities, governance and rights – as analytical entry points. These also provide a framework to identify research gaps and generate a comparative understanding of the impact of development processes and socioecological changes, including issues of climate change, adaptation and resilience, on gendered employment. Without an adequate analysis of gender, fisheries management and development policies may have negative effects on people’s livelihoods, well‐being and the environment they depend on, or fail altogether to achieve intended outcomes.     

Ammonia reduction in seawater by Yucca schidigera extract: efficacy analysis and empirical modelling

Yucca schidigera is a plant native to southwestern USA and Mexico. Its extract has been used in the livestock industry to control ammonia accumulation in animal holding facilities, and to reduce ammonia concentration in animal excreta. This study investigated the potential and effectiveness of Y. schidigera extract (YUPE) for ammonia reduction in seawater. A dose–response experiment was conducted to determine the effect of different concentrations of YUPE at 0, 18, 36, 72 and 108 mg L⁻¹ on total ammonia nitrogen (TAN) at 1, 3 and 9 mg L⁻¹. At a higher YUPE dosage rate, higher TAN reduction was observed, and TAN reduction was highest during the first 12 h, and decreased thereafter. A stepwise multiple linear regression that included the initial TAN, YUPE concentration and time was developed, which accurately predicted empirical TAN concentrations. Applications of this model for ammonia management strategies were formulated for hypothetical tiger prawn (Penaeus monodon) rearing conditions. YUPE's efficacy for ammonia reduction, natural origin and safety make YUPE a potentially suitable compound for water quality management in mariculture.     

耐盐红螺菌对水产养殖病害细菌的拮抗作用

为探明光合理细菌对水产养殖动物病害的生物防治功能，对病鳖、鳗及南美白对虾动物体上的病原菌进行分离、纯化与鉴定，人工感染健康动物检测致病性；探讨耐盐红螺菌对病害细菌分离株的仰菌效能，和有效抑菌作用时细胞所处的生长期。试验结果表明，水产动物病害细菌分离株为孤菌属，气单胞菌属和假单胞菌属菌株；耐盐红螺菌的代谢产物对商害细菌分离株均有抑制作用，其平坂柳菌圈为1.2-1.4cm，最低抑菌浓度多为4-8倍稀释液；耐盐红螺菌的拮抗物质随细胞对数生长过程中生成，至细胞衰亡期达到最大值。     

固定化微生物联合大型水生植物净化养殖废水的实验研究

在实验室条件下,以固定化菌种枯草芽孢杆菌(Bacillus megaterium)、弯曲芽孢杆菌(B.flexus)和大型水生植物粉绿狐尾藻(Myriophyllum aquaticum)为实验材料,研究微生物与水生植物两者单独或联合作用等不同处理模式对水体不同形态氮素的去除效果及氨化细菌(AB)、亚硝化细菌(NOB)、硝化细菌(NB)和反硝化细菌(DB)4类氮循环细菌的动态分布情况,实验阶段为25 d。结果表明,与固定化微生物(I)、粉绿狐尾藻(M)分别单独作用相比,两者联合作用(I+M)对水体氮素和CODMn的去除效果显著。比较实验前15天,I+M对养殖废水亚硝态氮(NO2-N)和铵态氮(NH4-N)的去除率分别达50.83%和62.38%,显著高于I(39.55%和51.17%)与M(40.78%和53.31%)(P<0.05)。实验结束时,I+M水体CODMn的去除率达67.23%,显著高于I(48.23%)与M(33.35%)分别单独作用(P<0.05);I+M对养殖废水硝态氮(NO3-N)的去除率高达88.74%,显著高于I(67.85%)(P<0.05),但与M无显著差异。另外,I+M植物根系表面4类氮循环细菌的数量相比M组均有不同程度的增加,而载体表面的4类氮循环细菌数量实验后期整体呈现下降趋势,其中I+M载体表面AB数量始终比I低1.8~2.6个数量级。主响应曲线分析(PRC)表明,水体浊度、NO3-N、TN等对造成组间差异的贡献较大,实验前中期I+M组对养殖废水的净化效果强于两者分别单独作用,但实验末期I组与UC组间的总体差异大幅度减小,且I+M与M的差异很小。结论认为,利用固定化微生物与粉绿狐尾藻联合处理循环养殖废水能有效提高对养殖水体NO2-N、NH4-N、CODMn等的去除效果,从而减轻氨氮和亚硝态氮等物质对养殖生物的毒害,使得养殖生物能维持正常的物质代谢,但在实际工厂化养殖生产中应综合考虑养殖废水的水质状况、固定化菌种组分及其生理生化特性、植物种类及搭配等因素,使反应器的设计更加科学以确保系统稳定、高效、持久地运行。本研究旨在为构建高效、稳定的养殖废水生态净化模式提供科学依据。     

5种滤食性贝类对牙鲆的粪便、残饵及网箱养殖区沉降物的摄食行为

采用室内静水法,研究了虾夷扇贝、栉孔扇贝、长牡蛎、紫贻贝及菲律宾蛤仔对不同浓度、质量的牙鲆粪便、残饵、沉降物的摄食行为,从摄食生理角度,分析了基于滤食性贝类的鱼+贝IMTA养殖模式的可能性。研究结果显示,这5种贝类对鱼粪、残饵及网箱周围沉降物都可摄食,但是,不同贝类对食物可获得性的反应不同。菲律宾蛤仔、长牡蛎、栉孔扇贝的摄食率显著高于其它2种贝类;5种贝类的吸收率、吸收效率无显著性差异。不同饵料对贝类的摄食行为影响显著。吸收效率(AE)都随有机物含量的增加而增大;对有机物的吸收率(AR)与有机物浓度(POM)呈线性正相关关系。颗粒物TPM浓度达到26.24,21.64,27.00 mg/L时,长牡蛎、栉孔扇贝、虾夷扇贝会产生假粪来调节摄入的能量。在牙鲆+滤食性贝类的IMTA养殖模式中,菲律宾蛤仔、长牡蛎、栉孔扇贝是比较好的候选种。     

工厂化水体LED光照沉水植物对氨氮的吸收

本文研究了沉水植物伊乐藻（Elodea nuttallii）在白色LED灯处理水产养殖中氨氮的效果。在50×33cm和45×28em鱼缸中放入体质量150±5g鲫（carassius auratus）7尾,放入伊乐藻1．2kg,应用白色LED灯为光源,用遮光纸遮光,放入28w循环泵进行交叉循环。12d饲养结果表明：伊乐藻不仅可吸收养殖排泄的氨氮、增加水体溶解氧,而且养殖鱼类代谢的二氧化碳可以促进沉水植物生长,具有生态循环利用的效能,为进一步研究循环水养殖的生态利用提供了参考。     

大连湾、辽东湾养殖水域有机氯农药污染状况

采用毛细管GC ECD法测定大连湾、辽东湾表层沉积物及表层、微表层海水中 16种有机氯农药 (OCP16 )的含量。结果表明 ,辽东湾海区表层海水OCPs平均质量浓度为 4 1.94ng/L ,显著高于大连湾海区 4 .5 2ng/L的平均值 ,但 2个湾OCPs质量浓度均未超出渔业水质标准。辽东湾表层沉积物OCPs平均质量分数为 10 .15ng/g ,也明显高于大连湾表层沉积物 6.17ng/ g的平均水平。表明辽东湾有机氯农药污染程度较大连湾重。大连湾各站位微表层海水OCPs含量显著高于表层水 ,显示微表层海水对OCPs有较强的富集作用 ,平均富集系数为 5 .1～ 15 .4。     

水产养殖活动中N2O的排放研究进展

本文分析了养殖水体氮转化过程中可能产生N_2O的环节,总结了关于水产养殖活动中N_2O排放量的相关研究进展。结果表明,养殖过程中的N_2O排放系数总体上低于废水处理过程中的N_2O排放系数;不同的养殖模式氮的利用效率及未被利用的氮的去向有较大差别,其中循环水养殖模式的氮处理过程最接近于废水处理厂中的处理途径,但循环水养殖产量占全球水产养殖产量的比例较低,且现有水产养殖总产量中约有一半的渔获物不需要投饵,因此,基于废水处理厂的N_2O排放系数和总养殖产量的N_2O排放量的估算会明显高于实际排放量。目前尚缺乏关于水产养殖N_2O产生的基础性研究,本研究未进行相关估算。应尽快开展水产养殖活动中产生N_2O的系统性研究,为客观评估养殖活动N_2O的排放提供理论支撑。