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151.
本试验对硬壳蛤(Mercenaria mercenaria Linnaeus)进行规模化土池人工育苗,包括亲贝培育、苗池清整、基础饵料培养、人工催产、浮游幼虫及稚幼贝培育、水质监测和敌害防除等。硬壳蛤土池育苗面积60亩,经过近7个月的人工培育,共培育苗种8.25亿粒(平均规格2861粒/kg),每亩产蛤苗1375.68万粒,亩利润20675元。 相似文献
152.
153.
分隔池塘养殖系统是绿色高效池塘养殖设施研究发展的重点方向之一。提出了分隔池塘养殖系统的定义,阐述了系统设计的原理和国内外发展历程,归纳了标准分隔池塘、简易分隔池塘和流水槽池塘3种国外发展的主要系统模式类型,通过文献收集和实地调研对3种系统模式的研究进展和发展趋势进行了系统的梳理,比较了国内外发展模式的养殖品种、水循环方式、研究概况和产业应用情况,通过进一步讨论分级序批养殖池塘、跑道池养殖池塘2种在国内具备良好发展前景系统模式的优缺点,提出了下一步的研究重点和发展方向,为分隔池塘养殖系统的结构优化和技术提升提供参考。 相似文献
154.
为了明确大黄鱼在大型围网养殖区内的分布规律,实验通过集成、构建具备大黄鱼探测以及水温、盐度、光照、pH、溶解氧等海洋环境探测功能的小型探鱼无人船,并在浙江省舟山市桃花岛大黄鱼围网养殖基地内开展了6次现场监测。结果发现,(1)在水平范围,大黄鱼主要分布在大型围网养殖区内礁石丰富且水流相对较缓的区域;(2)在垂直范围,大黄鱼主要分布在加权相对深度0.6~0.9的养殖海区中下层;(3)围网养殖海区内温度、盐度、pH、溶解氧等海洋环境条件整体变化较小,大黄鱼往往分布在光照强度分别为(5 921±2 702)、(50 799±50 988)、(5 990±542)、(3 494±695)、(6 836±4 761)及(15 395±5 531)lx等相对较弱的区域。本实验首次通过小型探鱼无人船系统研究了围网养殖区内大黄鱼的分布特性及相应的海洋环境因子对其分布的影响,结果为大黄鱼围网养殖区的操作平台选址、投喂管理、起网设计等提供了依据。 相似文献
155.
采用自行设计的抽屉式生物滤器应用于漠斑牙鲆(Paralichthys lethostigma)闭合循环水养殖系统,研究其对循环养殖水的处理效果及漠斑牙鲆的增重和饲料利用率的影响。结果表明:经过60 d的循环水养殖,漠斑牙鲆从初始时的(225.4±11.9)g增加到结束时的(337.5±10.3)g,增重率49.97%;试验饲料系数1.06,养殖密度24.1 kg/m3,成活率100%;抽屉式生物滤器对于NH4+-N、NO2--N和COD去除率分别为(10.61±1.88)%、(14.90±3.06)%和(16.11±1.70)%,可满足漠斑牙鲆养殖水体的水质要求。 相似文献
156.
From an environmental point of view, hydrogen peroxide (HP) has beneficial attributes compared with other disinfectants in terms of its ready degradation and neutral by‐products. The rapid degradation of HP can, however, cause difficulties with regard to safe and efficient water treatment when applied in different systems. In this study, we investigated the degradation kinetics of HP in biofilters from water recirculating aquaculture systems (RAS). The potential effect of HP on the nitrification process in the biofilters was also examined. Biofilter elements from two different pilot‐scale RAS were exposed to various HP treatments in batch experiments, and the HP concentration was found to follow an exponential decay. The biofilter ammonia and nitrite oxidation processes showed quick recuperation after exposure to a single dose of HP up to 30 mg L?1. An average HP concentration of 10–13 mg L?1 maintained over 3 h had a moderate inhibitory effect on the biofilter elements from one of the RAS with relatively high organic loading, while the nitrification was severely inhibited in the pilot‐scale biofilters from the other RAS with a relatively low organic loading. A pilot‐scale RAS, equipped with two biofilter units, both a moving‐bed (Biomedia) and a fixed‐bed (BIO‐BLOK®) biofilter, was subjected to an average HP concentration of ~12 mg L?1 for 3 h. The ammonium‐ and nitrite‐degrading efficiencies of both the Biomedia and the BIO‐BLOK® filters were drastically reduced. The filters had not reverted to pre‐HP exposure efficiency after 24 h, suggesting a possible long‐term impact on the biofilters. 相似文献
157.
158.
Fish contribute a significant amount of animal protein to the diets of people in Bangladesh, about 63% of which comes from aquatic animals. In Bangladesh, fish is mainly derived from two sources: capture and culture. Aquaculture has shown tremendous growth in the last two decades, exhibiting by about 10% average annual growth in production. Capture fisheries, although still the major source of supply of fish, have become static or are in decline due to over‐fishing and environmental degradation, and it is now believed that aquaculture has the greatest potential to meet the growing demand for fish from the increasing population. At present, aquaculture production accounts for about one‐third of the total fish production in Bangladesh. This paper examines the impact of an aquaculture development project in Bangladesh on food security, with particular emphasis on the poor. The analysis shows a positive impact of aquaculture development on employment, income and consumption. A number of implications for policy in areas that might strengthen these outcomes are discussed and recommendations are presented. 相似文献
159.
A Keramat Amirkolaie 《Aquaculture Research》2008,40(1):112-117
Artificial rearing of fry has been introduced as an alternative to supply fry and juvenile sturgeon in order to restock the depleted sturgeon population in the Caspian Sea. The aim of this study is to assess the feed selection characteristics of sturgeon (Acipenser persicus) fry during the period in which they stay in earthen ponds before being released into the river. Sturgeon fry weighing around 150 mg were introduced into five almost similar‐sized earthen ponds. The ponds were enriched with fertilizer to supply natural food for the fries. A weekly sample of six specimens was collected from each pond during the 5 weeks of the experiment. All collected fish were weighed and then dissected for inspection of the stomach and the intestine content. The overall stomach content measured from 150 fish showed that around 74% of the stomach content was composed of chironomids and the rest was daphnia and cyclops. At the beginning of the study (first 2 weeks), sturgeon fry feed more on daphnia and cyclops; this trend, however, reversed in the last 2 weeks of the study. In conclusion, sturgeon fry feed on three prey groups—chironomids, daphnia and cyclops—during their lifespan in earthen pond. Feeding on chironomids larvae increased with sturgeon fry size. 相似文献
160.
中国湖泊、水库水产增养殖技术的进展 总被引:6,自引:0,他引:6
中国湖泊可养面积187万公顷,水库可养面积200万公顷,总共占全国内陆可养水面的70%以上。这些水面既是我国渔业在本世纪末年产量达到1800万吨宏伟目标的潜力与后劲之所在,也是“八·五”期间本行业科技攻关的重点。 湖库资源特点与水产增养殖发展概要 (一)湖库资源特点 湖泊可养面积90%相对集中于平原地区,而水库总数的89.4%分布在长江、珠江和黄河三大流域的丘陵地区,具有良好的分布格局。湖泊面积在50平方公里以下的占总数的98%以上,水库中中小型的占99.6%,另有塘坝63万座,中小型水面有利于采取各种集约化措施。 相似文献