菲律宾的锯缘青蟹养殖

就东南亚的锯缘青蟹（ＳｃｙｌａｓｅｒｒａｔａＦｏｒｓｋａｌ）养殖而言，以菲律宾的产量最高，１９９３年产量为５６５３ｔ，１９９４年为４０８５ｔ，１９９５年为２７８２ｔ。鉴于菲律宾养殖锯缘青蟹的产量名列世界前茅，本文简要介绍其养殖及研究进展。一、锯缘青蟹...     

锯缘青蟹的几种养殖方式

锯缘青蟹(Scylla serrata)又称青蟹,分布于温带、亚热带和热带海域。我国浙江、福建、台湾、广东及广西沿海均有分布。青蟹肉味鲜美,是优良的食用蟹,也是我国出口创汇的珍贵海产品。温州地区70年代初的年产量约100吨,主要是捕捞产量。近十多年来,由于各种原     

海康县青蟹养殖技术

锯缘青蟹，其适应性强，管理容易，养殖周期短，投资风险小，经济效益高．近年来，海康县利用海水池塘养殖青蟹发展较快，1989年全县养蟹面积为3，068亩，总产值达268．4万元，盈利92.2万元,今年养蟹面积已超7，000亩，还有继续发展的趋势．为了交流养蟹经验，发展海水养殖业，现根据沿海群众几年来的养蟹实践，总结其养殖技术措施如下．     

湖南珍珠产业的现状与发展对策研究

湖南自然条件优越,气候宜人,育珠贝类资源丰富,发展淡水珍珠养殖具有得天独厚的条件。特别是在我省常德、安乡、汉寿、沅江、岳阳、华容等地,借助洞庭湖水的资源,淡水珍珠养殖规模越来越大,出现了"千     

鲆鲽鱼类饲料产业现状与发展对策

鲆鲽鱼类肉质细嫩，口感鲜美，营养价值高。大菱鲆（Psettamaxima）作为鲆鲽鱼类中重要的一种，1992年首次从英国引进，经过科学家几年艰辛的努力，高效的“温室大棚＋深井海水”工厂化养殖模式得到建立，自此大菱鲆养殖产业得到快速发展。到2008年，大菱鲆年产量达8万多吨、年产值超过100亿元。     

锯缘青蟹养殖技术

青蟹具有生长快、个体大、抗病力强等优点．是继梭子蟹后又一新的养殖品种，现将养殖技术介绍如下：１ 池塘选择与改造 地塘纳水便利凋围无工业污染。面积１～５０亩（１０亩左右较适宜）．水深 １～１．５ ｍ。池底以沙底或砂泥底为宜。池内滩面平缓，有深０．５ｍ、宽２ｍ的环沟，能排干池水。池内放置人工鱼礁，为青蟹提供隐蔽场所．如石板、瓦片、水泥管等。池堤四周有４０～５０ ｃｍ高的防逃设施（如塑料薄膜）。２ 养殖方法２．１ 蟹苗放养 池塘必须提前清淤，并经曝晒。４月初带网纳水 ２０ ｃｍ（滩面全部覆盖），每亩用茶籽饼 ２ …     

锯缘青蟹养殖技术经济探讨

本文对岛屿村四年来青蟹育肥所采取约技术要点及其经济效益进行探讨、分析。     

青蟹常见的病害与防治

青蟹的养殖过程中,由于天气、水温、水质及盐度的突变：水体中的有毒、有害物质及有害生物的侵袭：环境污染;饵料变质等,都有可能使青蟹患上疾病。随着青蟹养殖规模扩大及养殖时间的推移,青蟹的病害已逐渐被养殖者及研究人员所重视和认识。本文简单介绍了青蟹几种常见的病害及防治方法。     

三门县青蟹发展之思考

一、三门县青蟹发展现状青蟹，学名锯缘青蟹。早在５０、６０年代，三门青蟹就已在闽浙沪一带享有盛名，年销量达１００多吨。进入８０年代后，随着围塘养殖的兴起，青蟹围塘综合养殖技术不断成熟，养殖面积和产量成倍增长。至２００１年，全县青蟹养殖面积４万亩，产量７０００吨，产值达３．５亿元，占全省青蟹产量的一半。二、三门青蟹发展中存在的问题这几年，三门水产养殖业（尤其是青蟹产业）在当地政府的重视下，借农业产业结构调整东风，在量和质上都有很大的发展，整体素质提升较快，发展趋势较猛，态势较好，群众也从中得到了实惠…     

Economic evaluation of mud crab farming under different production systems in India

Abstract

Apart from penaeid shrimp culture, crab farming and fattening and other several diversified aquaculture practices are now emerging as viable ventures in India. About 11 types of crab products are being exported from India with an average unit value realization of US$ 3.73 kg^?1, pinpointing its importance in the foreign exchange earnings. An economic evaluation of mud crab culture, fattening and fattening with composite culture of shrimp/finfish has been attempted in this paper. The major operating cost was that of seed and it was higher for crab fattening (87% of the total operating cost). Feed costs were very low compared to that of shrimp farming. Annual profit obtained was US$ 22812.5 ha^?1 year^?1 for culture and US$ 30820.8 ha^?1 year^?1 for fattening. Economic indicators such as net profit, rate of return, pay back period and breakeven price indicate that crab fattening/culture is much more profitable than any other coastal aquaculture operations currently in practice, provided hatchery production is established in the country to ensure adequate supply of mud crab seeds.     

Stepwise function of natural growth for Scylla serrata in East Africa: a valuable tool for assessing growth of mud crabs in aquaculture

Predicting growth is critical in aquaculture, but models of growth are largely missing for mud crab species. Here, we present the first model of natural growth in juvenile and adult mud crabs Scylla serrata from East Africa using a stepwise growth function based on data on intermoult periods and growth at moult from field mark‐recapture, pond and laboratory studies. The results showed a sigmoid growth pattern in carapace width and suggest that S. serrata in East Africa will reach 300 g and sexual maturity ~9.9 months after settlement, and a commercial size of 500 g after 12.4 months. Analyses of the literature identified several issues with the common praxis to compare standard growth measures between aquaculture studies with different initial size or growing periods. Using the new growth function to estimate the proportional difference between modelled and obtained growth as an alternative method, we show that growth rates of S. serrata cultured in cage systems, which are dominant in East Africa, was <40% of the estimated natural growth and growth obtained in pond systems. The analysis also indicated that growth rates of S. serrata in Southeast Asia was over 50% higher compared with similar culture systems in East Africa, and that different species of mud crabs had large differences in growth rates. This study shows that growth in the present mud crab aquaculture systems in East Africa is below their expected potential. Further work is needed to identify the factors behind this observation.     

福建省水产养殖病害监测现状及建议

根据2002—2011年福建省水产养殖病害测报结果,总结分析了福建省主要水产养殖病害发生情况和流行特点,结果表明,福建省水产养殖病害发病周期长、范围广,且病害种数逐年增多;回顾近10年测报工作,福建省水产养殖病害监测在建立测报网络、提高测报队伍素质、强化病害测报工作机制和测报防治结合等方面取得了一定成效;针对目前水产养殖病害监测存在经费缺乏、测报队伍不稳定、基层技术力量薄弱和监测、诊断手段落后等问题,提出相关对策与建议。     

Ovarian maturation stages of the mud crab Scylla serrata

Ovarian maturation in adult wild‐sourced and pond‐grown Scylla serrata (Forsskål) was determined based on gross morphology and histological appearance. There were no significant differences noted in the histological features of both wild and pond‐reared S. serrata females. Ovarian maturation was classified into five stages: immature, early maturing, late maturing, fully mature and spent. The immature ovaries are thin and translucent to off white and contain oogonia, primary oocytes with large nuclei. The follicle cells were found around the periphery of the lobes and an area among groups of oogonia and oocytes. The follicle cells gradually enclosed the oocytes. The early‐maturing ovaries were yellow and small yolk globules started to appear in larger oocytes. In late‐maturing ovaries, the colour became light orange and lobules were apparent. Yolk globules occurred in the cytoplasm with larger globular inclusions towards the periphery, while follicle cells were hardly recognizable. Fully mature ovaries were orange to deep orange and had swollen lobules. Large yolk globules were apparent in the entire cytoplasm. Follicle cells were hardly seen. Spent ovaries were similar to the early‐maturing and late‐maturing stage in partially spawned females. The ovarian development was correlated closely to the gonadosomatic index, oocyte diameter, and ovarian histology. The classification of ovarian maturation provides baseline information for further studies on reproductive biology. Likewise, the information provides a guide for broodstock management in the hatchery.     

山东设施渔业发展现状及对策建议

设施渔业是通过科学的管理和先进的养殖设备,实现水产养殖优质、高产、高效的一种新的生产方式,是现代渔业发展的必然趋势。山东省是水产养殖大省,其设施渔业的发展也一直走在全国的前列。文章在描述了设施渔业的定义和产业特点之后,结合山东省发展设施渔业的条件,在现状描述的基础上,针对其在设施渔业发展中存在的问题,提出了相关对策建议。     

我国海水蟹类养殖现状与发展目标

回顾总结了我国海水蟹类养殖产业发展现状,包括:青蟹工厂化育苗和梭子蟹土池仿生态育苗技术,苗种运输方法和中间培育技术,微卫星分析技术、SSR技术等生物技术在海水蟹类良种选育上的应用,以多品种生态养殖为主的海水蟹类养殖模式等;探讨了影响产业可持续发展主要问题,提出了产业发展的目标.     

Effects of tank colour on larval survival and development of mud crab Scylla serrata (Forskål)

Hatchery culture of mud crabs has not yet achieved commercial viability despite decades of research efforts. Further research is therefore needed to better understand larval culture requirements of the crab. Based on anecdotal observations, an experiment was carried out to test whether the background colour of the culture vessel affected larval culture success. Newly hatched larvae of Scylla serrata were reared in culture vessels of five colours, i.e., black, dark green, maroon, sky blue and white. Larval survival and development were monitored daily until all of them either moulted to the first crab stage or died. The results showed clear effects of background colour on larval survival. A general tendency of higher larval survival in darker‐coloured backgrounds was evident. In particular, overall zoeal survival for larvae reared in black vessels was significantly higher than those reared in white ones. Background colour also appeared to affect larval development. Larvae reared in darker backgrounds generally had shorter development times and more synchronized moulting. A significant delay in zoeal development was observed in larvae reared in white vessels. Dark backgrounds possibly facilitated more efficient feeding, reduced settlement of larvae at the bottom of the vessels as well as minimized stress. This result appears to be the first to demonstrate that background colour can significantly affect larval survival and development of a crustacean species.     

Diet and harvesting regimen for the production of mud crab Scylla olivacea in brackish water ponds

ABSTRACT:   The effects of diet (fish bycatch or a mixed diet of 75% brown mussel flesh and 25% cooked cracked corn) and harvesting regimen (bimonthly selective harvesting, or single terminal harvesting) on growth, survival and production of mud crab Scylla olivacea (Herbst) in brackish water ponds were determined in a replicated factorial experiment. The crabs were stocked at 0.6 individuals per m² for 118 days. There was no significant interaction ( P  > 0.05) between the diet and harvesting regimen treatments. Regardless of diet, the survival rate and net production of mud crabs were significantly higher ( P  < 0.05) when crabs were subjected to bimonthly selective harvesting than at single terminal harvest. Comparative cost–return analysis showed that bimonthly selective harvesting and mixed diet treatments attained higher net return and return on investment, and lower cost of production than the other treatments. Partial budgeting analysis showed that bigger profits can be earned by using a bimonthly selective harvesting and a mixed diet of 75% fresh or fresh-frozen brown mussel flesh and 25% cooked cracked corn.     

河蟹青虾混养池塘循环水净化效能的初步分析

在河蟹青虾混养池塘构建封闭式循环水养殖系统,并对其净化效果和养殖效益进行了初步研究。结果表明：该系统对水体TN、TP、NH4＋-N和CODMn的平均净化效率分别为27.33%、56.14%、43.91%和39.59%。经湿地净化后的水质能够达到GB3838-2002地表水Ⅲ类排放标准,平均纯收益达53769元/hm2。     

Characterization of Aquimarina hainanensis isolated from diseased mud crab Scylla serrata larvae in a hatchery

Mass mortality due to necrosis signs occurred in hatchery-reared zoea stage larvae of the mud crab Scylla serrata in Okinawa, Japan, and a causative bacterium was isolated. In this study, we identified and characterized the bacterium by genome analysis, biochemical properties and pathogenicity. The bacterium was a Gram-negative, non-motile, long rod, forming yellow colonies on a marine agar plate. It grew at 20–33°C (not at 37°C) and degraded chitin and gelatin. Phylogenetic analysis of the 16S rRNA gene sequence identified the bacterium as Aquimarina hainanensis. Genome sequence data obtained from Illumina MiSeq generated 29 contigs with 3.56 Mbp in total length and a G + C content of 32.5%. The predicted 16 chitinase genes, as putative virulence factors, had certain homologies with those of genus Aquimarina. Experimental infection with the bacterium conducted on larvae of four crustacean species, brine shrimp Artemia franciscana, freshwater shrimp Caridina multidentata, swimming crab Portunus trituberculatus and mud crab S. serrata, revealed that this bacterium was highly virulent to these species. The present study suggests that the bacterium caused mass mortality in mud crab seed production was A. hainanensis and can be widely pathogenic to crustaceans.