黄海北部中国对虾放流增殖效果的变化

分３个阶段总结黄海北部中国对虾放苗增殖效果，第一阶段（１９８５～１９８８年）放流效果好，回捕率高，平均投苗量７．６亿尾，平均捕捞产量２２００吨，平均回捕率约１１．６％，第二阶段（１９８９～１９９２年）放流数量多，但回捕率低，平均投苗量１６．７０亿尾，平均回捕率约６．７％，第三阶段（１９９３～１９９５年）平均投苗量７．１８亿尾，平均回捕率约２．３３％，回捕效果极差，下降原因：一是客观原因造成，如污染     

莱州湾东部近海黑鲷标志放流效果初探

摘要2011年,课题组在莱州湾东部芙蓉岛海域开展黑鲷标志放流研究,共放流平均体长8．6cm以上黑鲷苗种23．6万尾,其中有效挂牌标志放流68224尾。标志鱼经暂养4天后,脱牌率和死亡率分别为1．88％和2．03％。9—11月,通过地笼网回捕、回捕电话统计和实地走访3种方式累计回捕标志黑鲷1041尾,回捕率为1．53％,其中放流后20～30天和30—40天,标志鱼的回捕率较高,分别为0．63％和0．48％。回捕标志黑鲷的生物学分析表明,10月份,放流鱼生长缓慢,叉长日均增长0．53mm,之后生长速度加快,11）7份又长日均增长达到0．85mm。放流鱼主要分布于鱼礁海域,并随着水温降低,逐渐向渤海湾口移动。     

河蟹增殖效益高

浙江省平阳县内陆水域辽阔,河流纵横交错,水质肥沃,气候适宜,具有河蟹增殖的优越条件。该县1987年人工放流392.5公斤河蟹苗,增殖面积2.8万亩,计8个区、40个乡。据初步调查,全县有3300多捕蟹户,1988年捕获河蟹167吨,产值267.2万元。如练川乡下姜自然村有82户,捕蟹收入3万多元。捕蟹能手姜盛龙,捕蟹三个来月,收入4000多元,占家庭总收入80％以上。经测算,放流1公斤河蟹苗,增殖425公斤;     

山东半岛南部海域三疣梭子蟹增殖放流群体回捕率

根据2010年和2011年5-8月在山东半岛南部海域对三疣梭子蟹(Portunus trituberculatus)增殖放流前后分别进行的每年3个航次的对比调查结果,定量分析了三疣梭子蟹自然群体和增殖放流群体的数量,并根据三疣梭子蟹放流苗种数量和放流后捕捞产量,对三疣梭子蟹增殖放流群体回捕率进行分析.研究结果表明,2010年5月山东半岛南部海域三疣梭子蟹增殖放流前自然群体资源量很少,相对资源密度为0.90 ind/(站.h);在5-6月共放流苗种11 015.13万只,放流后10d左右资源量增加为26.08 ind/(站.h),放流群体所占的比例为96.55％;8月进行调查的相对资源密度为1.70 ind/(站.h),当年生群体数量占所有群体数量的比例为64.29％;9月、10月、11月秋汛期间捕捞产量为3 108 t,捕捞个体平均质量为232.3 g,增殖放流群体回捕率为7.54％.201 1年5月山东半岛南部海域三疣梭子蟹增殖放流前自然群体相对资源密度为1.70 ind/(站.h);在5-6月共放流苗种13 132万只,放流后10d左右资源量增加为29.15 ind/(站.h),放流群体所占的比例为94.17％;8月进行调查的相对数量为1.00 ind/(站.h),当年生群体数量占所有群体数量的比例为70.00％;9月、10月、11月秋汛期间捕捞产量为2 896 t,回捕个体平均质量为226.0 g,增殖放流群体回捕率为6.43％.除2011年胶州湾海域由于富营养化水质较差,以及其他因素对黄家塘湾海域的影响导致这两个放流点放流群体回捕率偏低外,2010年和2011年山东半岛南部放流海域整体水质良好,水温、透明度、盐度、营养盐比例、生物饵料等均比较适中,属于放流环境条件较佳的海域,比较适合三疣梭子蟹生长,放流群体回捕率整体上处于较高水平.     

暂养幼蟹的生活习性及其暂养措施

目前，我国已在河蟹人工繁殖技术、蟹苗捕捞和运输，放流和放养技术管理以及河蟹回捕率测算等方面，做了大量研究、推广工作，并取得了重大成果。但在河蟹蟹苗暂养(中间培育)的环节上，至今还未见到研究报告。为了进一步提高自然资源利用率和提高河蟹放流的经济效益，我站在上海市水产技术推广站的指导下，对蟹苗生活习性(幼蟹1～3期)、暂养池结构、暂养密度、饲养管理以及出池规格等诸方面做了一些探索性试验，     

海洋岛渔场放流增殖对虾效果显著

黄海北部海洋岛渔场，自1985到1987年，累计放流3厘米长的虾苗16亿尾。三年来秋汛累计回捕放流对虾4000多吨，产值1亿多元，回捕率占10％，为出口创汇发展外向型经济作出了贡献。     

围网养蟹回捕率低的原因及解决办法

近年来，随着大水面河蟹养殖的发展，围网养蟹以其节省饲料和养成规格大、品质好而得到迅猛发展，仅我县东平湖区就有几千亩围网养蟹面积。根据几年的养殖情况看，不少围网养殖存在河蟹回捕率差（有的回捕率仅２０％左右），单位面积产量低。现根据我地的情况，分析围网养蟹回捕率低的原因，并介绍一些解决方法，供参考。１围网养蟹回捕率低的原因１．１苗种质量差从目前看，大多养殖者不是自己培育蟹种进行养殖，而是到外地购买蟹种。由于缺乏蟹种鉴别知识，不少人所购买的蟹种存在着这样那样的问题，或是辽蟹、或是瓯江蟹；有的还掺有性成…     

岱衢族大黄鱼放流增殖试验

为了恢复舟山渔场本地种岱衢族大黄鱼（Pseudosciaenac Focea）资源,2000～2009年进行了岱衢族大黄鱼增殖放流试验。10年间共放流了经过人工繁育的岱衢族大黄鱼苗种1288．0×10^4尾,其中包括标志鱼62680尾。回捕标志鱼1432尾,平均回捕率2．73％。回捕试验结果表明,在岱衢洋进行本地大黄鱼的放流可行,体外挂牌法适合于大黄鱼的标志放流,放流鱼苗不仅可以成活、生长,还能够产卵、增殖并进行洄游;放流使舟山渔场本地岱衢族大黄鱼资源得到显著恢复,并产生了一定的经济效益。     

湖泊投放幼蟹的养殖效果

自1973年起,有关单位就在本市梁子湖等湖泊进行蟹苗的人工放流工作。一般认为,蟹苗在湖泊中成活率不高,通常回捕率只有2～5％,有的仅为1％左右。近三年,我们改投放蟹苗为投放一龄幼蟹,效果较为显著。现将本市主要湖泊1988年生产河蟹的效果报告如下: 一、试验条件地理条件:投放幼蟹的工作分别在移山湖、虾子径、涂正湖和红莲池进行。这些湖泊位于长     

谈中小型湖泊的河蟹捕捞

笔者以河蟹的生物学特性为基础,对中小型湖泊放养幼蟹后的回捕时间及捕捞工具等技术问题进行了讨论,尤其是对网簖与刺网的适宜湖区作了分析。1988年在湖北移山湖(5000亩)和虾子径湖(3000亩)放养的一龄幼蟹,采用网簖与刺网相结合,回捕率分别达到31.42％和40.17％。     

东海三疣梭子蟹成熟群体生殖特征和条件状况

为了探求东海三疣梭子蟹成熟群体的发育生殖机制,采用生态学、资源生物学等相关研究方法,通过对三疣梭子蟹性腺、肝胰腺及条件指数等指标的研究,初步建立起雄性三疣梭子蟹成熟阶段发育分期的特征变化,反映了目前东海三疣梭子蟹成熟群体的生殖特征和条件状况。三疣梭子蟹生殖群体由1龄蟹为主,规格偏小。头胸甲宽主要分布在100~160 mm之间,体重为50~200 g。头胸甲宽与长呈线性相关,而头胸甲宽、长与体重则呈幂函数关系。成熟阶段输精管发育程度和头胸甲宽正显著相关。根据三疣梭子蟹输精管的粗糙程度、管径及管重大小,本文首次提出把处于成熟阶段的雄蟹分为5个阶段。输精管重增长为幂函数方式,输精管指数则随发育线性增长。雌蟹卵巢发育规律和头胸甲宽之间关系不甚明显,而和季节相关。研究表明,9月份三疣梭子蟹交配后卵巢迅速发育,增长明显,10~12月份生殖群体卵巢普遍处于Ⅱ~Ⅳ期。三疣梭子蟹肝胰腺重量随体重和甲壳的增长而增加,而肝体指数相反。雌蟹卵巢Ⅱ期阶段梭子蟹肝胰腺重量最高,平均重量为18.21±5.68 g,随后逐渐降低,说明肝胰腺能量发生了转移;相比于雄蟹,雌蟹储能更多。雌蟹卵巢重量随肝胰腺重量变化呈对数关系增长,而雄蟹输精管重随肝胰腺重呈线性。三疣梭子蟹生殖群体在发育变化过程中两个条件指数基本处于一个平衡阶段,雌雄间差异变化不大。     

An ecosystem-based assessment of the Korean blue crab trammel net fishery in the Yellow Sea and management implications

Landings in the blue crab, Portunus trituberculatus, fishery in Korean waters of the Yellow Sea have declined substantially from 11,000 t in the 1980s to 2,300 t in 2004. Blue crab habitat quality in the Yellow Sea has been degraded by anthropogenic activities including sand mining, land reclamation, and coastal pollution. Various traditional management measures have been implemented, including closed seasons during spawning and size limits, but these measures alone have been unsuccessful to conserve blue crab stocks. Consequently, a total allowable catch and a stock-rebuilding program using an ecosystem-based management approach were implemented in 2003 and 2006, respectively to rebuild blue crab stocks and restore habitats. This program involved assessment of both blue crab stock status and trammel-net fishery impacts at an ecosystem-level using an ecosystem-based fisheries assessment method ( [Zhang et al., 2009] and [Zhang et al., 2010]), which considered fishery data from catch and effort time-series, crab population biology, and ecosystem characteristics, including habitats and environmental conditions. Recent (2008) management status indices have shown significant positive change compared to conditions in 2000 with respect to sustainability of the stock and fishery and with regards to biodiversity and ecosystem habitat quality.     

Proposed harvest control rule for managing the snow crab stock in the southwestern Gulf of St. Lawrence,Canada

We developed limit and target harvest control rules based on an age-, sex- and stage-structured model for managing the southwestern Gulf of St. Lawrence snow crab (Chionoecetes opilio) stock. We determined an F_x% (F resulting in a spawning biomass-per-recruit equivalent to x% of virgin spawning biomass-per-recruit) as a proxy for F_MSY and a minimum spawning stock biomass to open the fishery to incorporate them into the control rules. We evaluated the selected limit and target control rule parameters under stochastic simulations by considering various performance statistics. Because of the complexity in determining an effective female spawning biomass that involves a mating ratio, we choose the total mature male biomass (MMB) regardless of crab size as the spawning index to develop the stock–recruitment relationship for stochastic simulations. The MMB based F_37% appears a reasonable proxy for limit control rule while F_45% appears a reasonable target control rule. The corresponding limit and target harvest rates of legal size crab when the standing stock MMB exceeds the proxy MSY level are approximately 36% and 25%, respectively. The difficulty in establishing an appropriate stock–recruitment relationship for this stock was recognized hence a precautionary F_45% target level was chosen. Scenarios under biomass independent random recruitment were also investigated and performances of F_37% and F_45% control rules under this hypothesis behaved similar to those observed under S–R model based simulations.     

Paralytic toxins in Taiwanese crab Xanthias lividus

ABSTRACT: Paralytic toxicity was detected by tetrodotoxin (TTX) bioassay in four and five specimens of new toxic xanthid crab Xanthia lividus collected from Lanyu, south-east Taiwan in April 1999 and Hsiaoliuchiu south-west Taiwan in November 1999, respectively. The average toxicity of crab specimens collected from Lanyu and Hsiaoliuchiu was 230 ± 94 (mean ± SD) mouse units (MU) and 241 ± 114 MU, respectively. The toxin was partially purified by YM-1 membrane ultrafiltration and Bio-Gel P-2 column chromatography. Electrophoresis, high-performance liquid chromatography and gas chromatography–mass spectroscopy analyses showed that the crab toxin was composed mainly of tetrodotoxin (83%), as well as a small amount of gonyautoxin 1-4 (17%).     

Development and application of crab culture in the development of Chinese mitten crab industry of Shanghai

Chinese mitten crab is a unique aquatic product in China. As a highly nutritious, delicious, and intriguing food, it is deeply loved by consumers. Through field visits and household interviews in Chongming District of Shanghai and Suzhou of Jiangsu Province, the author collected relevant materials and made a detailed analysis of the strengths and weaknesses, opportunities and threats of the development and application of crab culture in the development of Chinese mitten crab industry in Shanghai by using SWOT model. The results show that the development and application of crab culture in the development of Chinese mitten crab industry in Shanghai can adopt growth‐oriented, transformation and upgrading, diversification and defensive development strategies. It is expected to promote the sustainable development of Chinese mitten crab industry in Shanghai through the development and application of crab culture.     

长江口中华绒螯蟹雌性亲蟹自然群体与放流群体血淋巴生化指标的比较

在长江口中华绒螯蟹(Eriocheir sinensis)亲蟹生殖洄游期间,对比研究了不同性腺发育时期的长江口中华绒螯蟹雌性亲蟹自然群体和放流群体9项血淋巴生化指标的差异。结果表明,洄游亲蟹在性腺发育的不同时期,放流群体与自然群体血淋巴总蛋白、血蓝蛋白、甘油三酯、肌酐、Ca2+及Mg2+含量水平上均无显著差异(P>0.05)。放流群体亲蟹在性腺发育到Ⅳ、Ⅴ期时的血淋巴白蛋白含量和性腺发育到Ⅳ期时尿素含量均显著高于自然群体(P<0.05),总胆固醇含量在性腺发育到Ⅵ期时显著高于自然群体(P<0.05)。在性腺发育过程中放流群体的大部分血淋巴生化指标与自然群体都无显著差异,仅在性腺发育到Ⅳ期后少数指标存在一定差异,表明放流群体通过自身调节能够很好地适应长江口环境并完成性腺发育过程。     

育肥时间对三疣梭子蟹卵巢发育和营养品质的影响

采用育肥养殖实验和生化分析技术,研究了育肥时间对三疣梭子蟹雌体卵巢发育和营养品质的影响。结果发现,(1)经90 d育肥的雌体卵巢指数显著上升,出肉率和总可食率呈先上升后下降趋势,育肥30~60 d的总可食率达42%以上。(2)育肥时间对肌肉中常规营养成分含量无显著影响,育肥60 d卵巢和肝胰腺中的蛋白质、脂肪和碳水化合物含量最高,水分含量最低;育肥使肝胰腺和卵巢中胆固醇百分含量呈显著下降趋势,育肥后期卵巢和肝胰腺中的磷脂含量显著上升;就不同组织而言,肝胰腺中的甘油三酯含量最高。(3)育肥使卵巢和肝胰腺中的单不饱和脂肪酸呈上升趋势,而多不饱和脂肪酸呈先下降后上升趋势,肌肉中脂肪酸组成无显著变化;整体上,肌肉的脂肪酸营养价值优于肝胰腺和卵巢。(4)育肥早期卵巢中氨基酸含量显著上升,整个育肥过程中肌肉中的甜味氨基酸含量呈显著上升趋势,育肥60 d后卵巢和肌肉中所有必需氨基酸分值均大于100,无限制性氨基酸。研究表明,生殖蜕壳后的三疣梭子蟹雌体适宜育肥时间为60 d,育肥不仅提高了总可食率,且优化了其营养价值。     

阳澄湖中华绒螯蟹品质分析

本文对江苏省阳澄湖产中华绒螯蟹的商业品质,按商业品级和雌、雄,测定了其各部分含量和各项营养成分。该湖所产河蟹符合江南水乡青背、白肚、金瓜、黄毛的大闸蟹形态特征,肌肉、肚脏及性腺三大可食部分共占体重的３６．７２％,壳、鳃、胃及心脏四大非可食部分共占体重的５３．２６％。另有１０．０２％为血淋巴和组织液。一、二级商品蟹的雌蟹可食部分各高出雄蟹５．２８％和６．５５％,营养成分中,雌蟹的脂肪显著高雄蟹。在实     

不同交配,越冬方式对河蟹育苗的影响

不同交配、越冬方式对河蟹育苗产量有着显著的影响，三年的生产实践表明：秋季室外土池交配的抱卵率、抱卵量明显高于水泥交配；秋季交配优于春季交配；室外土池自然越冬抱卵卵蟹的胚胎发育优于室外塑料大棚保温越冬的抱卵蟹。适宜的秋，春交配有利于河蟹多苗育苗，延长生长期，增加产量。     

Movement of adult male snow crab, Chionoecetes opilio, in the southern Gulf of St. Lawrence and eastern Nova Scotia, Canada

A total of 12,755 adult male snow crabs (Chionoecetes opilio) were tagged with spaghetti–Carlin tags in 33 sites throughout the southern Gulf of St. Lawrence (sGSL) and eastern Nova Scotia (eNS) between 1993 and 2003. Of the 1971 tag returns obtained between 1994 and 2004, 1703 had accurate geographical recapture positions. The average distance travelled was 16.7 km for sGSL (maximum 165 km) and 61.5 km for eNS (maximum 368 km). The release site and the number of days at liberty before recapture were significant factors affecting the distance travelled by the crabs. Size had no significant effect on the distance travelled or the direction of movement. The present observations support the sedentary nature previously reported for the sGSL snow crab stock, but not the eNS stock, where the movement of snow crab was more dynamic. In both regions, there were movements between management areas, which indicates that managing the fisheries in discrete units is not warranted.