文蛤滩涂养殖技术

为了进一步发展滩涂养殖业，发挥资源优势，1995－1998年，辽宁省加强了文蛤滩涂养殖技术推广工作，取得较好的经济效益和社会效益。现将主要技术介绍如下：一、养殖场地选择根据文蛤的生态习性和养殖特点，选择养殖场地时主要进行三方面的考虑：一是养殖场区潮流畅通，饵料生物丰富，水质无污染；二是便于看护管理和采捕作业；三是夏秋季节退潮露滩时间适中，不会因暴雨或曝晒而死亡。1．进行滩涂底质调查。选择含沙量70-80％，滩质稳定平坦的中、低潮区作为文蛤养殖场区。2．进行水质调查。选择水质无污染、盐度适宜，风浪较小、潮流畅通…     

高温季节培育日本对虾二茬苗的技术措施

近年来，辽宁沿海地区开展了日本对虾二茬苗养殖，需要在７月中旬至８月上旬提供苗种。本文提出了高温季节日本对虾苗生产应采取的一些技术措施。     

滩涂养殖菲律宾蛤仔死亡及生态环境效应调查研究

滩涂养殖菲律宾蛤仔死亡高峰发生在繁殖盛期的８月下旬至９月中旬，死亡率最高达８５．４％，高死亡区主要分布在潮间带中，上潮区的粘土质结构滩涂。死亡蛤仔个体相对大的占的比重大，高龄的比低频的死亡率高。     

贝类养殖技术之五文蛤大范围死亡原因探讨

文蛤(MeretrixmeretrixLinnaeus)是一种栖息在中低潮线及浅海区域、以沙为主的沙泥底质的双壳类软体动物，在适宜含沙量为70%左右的滩涂中生长，也是我国传统滩涂养殖的主要贝类之一，养殖范围较广，但近几年文蛤养殖却出现大范围死亡。一、死亡案例1.2003年6月中、下旬，启东市和如东县相继发生养殖文蛤大规模死亡。从6月上旬开始，上述地区已发现少量文蛤死亡现象；6月中旬至下旬，从启东寅阳、东海、近海、东元、天汾到如东的掘东、大豫、腰沙直至拼茶养殖场都有发生，造成文蛤成贝和苗种近万吨死亡，经济损失9000多万元。文蛤死亡的区…     

暗纹东方Tun苗种期生长规律的研究

在湖泊网箱培养条件下，河Ｔｕｎ鱼苗种生长特点是，全年体长呈均衡增长，其中８月中下旬－１０月中旬发为体长主要增长期，体重前期增长不平稳，中期体重剧增为主要增长期，后期又趋向平稳；体长与体重生长指数方程为Ｗ＝０．０１５８Ｌ＾３．３８５７，鱼龄１→１龄年增积量为０．８２７６ｃｍ．ｋｇ。     

辽西海域日本对虾生产性移植放流试验

１９９８年５月 ２４～２９日，在辽宁省葫芦岛市连山湾近岸水域放流体长１０．６±１．１ｍｍ的日本对虾２ ７９８．８万尾。 ８月中旬～１０月中旬期间，沿岸作业的 ５３４只渔船兼捕到本种商品虾 ２４．５ ｔ，平均体长 １４７．３ｍｍ，平均体重 ４０．７ ｇ，相当于 ６０．３万尾，回捕率为 ２． １５％，放流投资与增殖虾产值的比例为 １：５．４，效果良好。     

莱州湾金城海湾扇贝养殖海区防牡蛎附着的研究

１９９９年６￣８月，在莱州湾莱州市金城镇海湾扇贝养殖区，研究了牡蛎幼虫对海湾扇贝的附着规律。在养殖海区，离岸１５００ｍ以外纵向设立了３个定点站，近岸１５００ｍ海区作为一个观察点。结果表明，牡蛎主要为长牡蛎和褶牡蛎，６月下旬水温达到２２￣２３℃时，海水中出现牡蛎幼虫密度最高峰期（９５０个／ｍ＾２），主要为长牡蛎；８月中旬水温降到２７￣２６℃时出现次高峰（３７０个／ｍ＾２），主要为褶牡蛎。水温是监视牡     

泥螺在江苏沿海的引种、人工育苗及围养技术

<正>泥螺是潮间带底栖动物,生活在中低潮区泥沙质或泥质的滩涂上,退潮后在滩涂表面爬行,在阴雨或天气较冷时,潜于泥沙表层1~3cm处,不易被人发现,日出后又爬出觅食,以底栖藻类、有机碎     

罗氏沼虾幼虾温流水培育技术

新疆地处我国西北内陆地区，年适宜罗氏沼虾生长所需温度的时距较短，每年５月中旬和９月中旬常有气温突降现象出现。因此在气温稳定适宜罗氏沼虾生长的时间，能否提供大规格幼虾放养是影响新疆地区罗氏沼虾养殖成效的关键因素。为此，我公司在１９９６年～２０００年利用温流水池进行罗氏沼虾大规格幼虾的培育试验，取得较好的效果，现将培育技术总结如下。１ 培育池条件 培育池设在玻璃温棚内，为５０ｍ２或１００ｍ２水面，池深 ２ｍ，水深 １．８ｍ；长方形，有独立的进排水，阀门拄制进排水量，进水管设在鱼池前顶部，排水口设在鱼池后…     

池塘养殖罗氏沼虾技术与方法

池塘面积２．６亩，池深１．７ｍ，条石浆砌池壁，池底淤泥１０～２５ｃｍ，配１．１ｋｗ增氧机一台。５月初清池后施基肥，５月中旬至６月中旬放养淡化虾苗６．８万尾，鲢鱼水花２．５万尾；饲料种类有黄豆、螺蚌、颗粒饲料及过期食品等。９月底至１０月上旬出池，产出成虾２６７ｋｇ，鲢鱼２００ｋｇ；亩平产虾１０２．７４ｋｇ，亩平获利４３８９元。     

A comparison of the gametogenic cycle between the Pacific oyster Crassostrea gigas and the Suminoe oyster Crassostrea rivularis in Washington State

The gamotogenic cycle of the Suminoe oyster, Crassostrea rivularis, was compared with that of two groups of Pacific oysters (Crassostrea gigas) on an intertidal oyster bed in Oakland Bay, Washington. The Pacific oysters exhibited an earlier and more extensive development of gonad relative to C. rivularis. Resulting carbohydrate depletion was much greater in C. gigas relative to C. rivularis. Both groups of Pacific oysters spawned completely in mid-August. C. rivularis did not spawn but, rather, initiated phagocytosis of gametes by leucocytes. The implications of the results on the development of a marketable “summer” oyster are discussed.     

Experimental deepwater culture of the Sydney rock oyster (Crassostrea commercialis = Saccostrea cucullata): II. Pontoon tray cultivation

Pontoons made from plastic pipe were tested as an alternative to racks for deepwater culture of the Sydney rock oyster. The growth and mortality of oysters permanently suspended in water on trays beneath floating pontoons were compared with oysters on trays in an intertidal zone. For both culled spat (30–31 g whole oyster weight) and seconds oysters (37–39 g) beneath pontoons the growth rate, measured by weight increases, was three times that of oysters on intertidal racks over a 5-month period. Mortality (from unknown causes) was higher beneath the pontoons. The mean mortality of spat oysters was 40% compared with 24% on the intertidal trays, and for seconds oysters was 51% compared with 34%.     

Where land meets sea: Intertidal areas as key-habitats for sharks and rays

Intertidal habitats (i.e. marine habitats that are (partially) exposed during low tide) have traditionally been studied from a shorebird-centred perspective. We show that these habitats are accessible and important to marine predators such as elasmobranchs (i.e. sharks and rays). Our synthesis shows that at least 43 shark and 45 ray species, of which 54.5% are currently threatened, use intertidal habitats. Elasmobranchs use intertidal habitats mostly for feeding and as refugia, but also for parturition and thermoregulation. However, the motivation of intertidal habitat use remains unclear due to limitations to observe elasmobranch behaviour in these dynamic habitats. We argue that elasmobranch predators can play an important role in intertidal food webs by feeding on shared resources during high tide (i.e. ‘high-tide predators’), which are accessible and also consumed by terrestrial or avian predators during low tide (i.e. ‘low-tide predators’). In addition, elasmobranchs are able to change the bio-geomorphology of intertidal habitats by increasing habitat heterogeneity due to feeding activities and may also alter resource availability for other consumers. We discuss how the ecological role of elasmobranchs in intertidal habitats is being affected by the continued overexploitation of these species, and conversely, how the global loss of intertidal areas poses an additional threat to an already vulnerable taxonomic group. We conclude that studies on intertidal ecology should include both low-tide (e.g. shorebirds) and high-tide (e.g. elasmobranchs) predatory guilds and their ecological interactions. The global loss of elasmobranch predatory species and intertidal habitat provides additional compelling arguments for the conservation of these areas.     

Preliminary studies to culture mangrove oysters, Crassostrea tulipa, in Sierra Leone

Large quantities of wild mangrove oysters Crassostrea tulipa exist in the intertidal zone of the rivers and estuaries of Sierra Leone. Typically, the wild mangrove oysters are small due to crowding and stress induced by the high ambient temperatures and lack of food at low tide when the oysters are out of water. The wild oysters measure on the average 2.5 cm and weigh 1.5 g for a 2-year growing period.Preliminary studies have been made since 1974 to identify viable culture techniques that will increase the yield (growth rate and size) of mangrove oysters. Suspended culture (rack and raft) was found to be most promising with rafts producing an average 7-cm and 7-g oyster in 7 months. Biological work summarized includes plankton, fouling and bacteriological studies. Some cost-benefit studies are also included.     

Experimental deepwater culture of the Sydney rock oyster (Crassostrea commercialis): III. Raft cultivation of trayed oysters

Sydney rock oysters, normally intertidal, were submerged below rafts in vertical stacks of 15 oyster trays extending 2 m deep. Growth rates and mortality were not good or economically encouraging. The best growth was from small culled spat (43 whole oysters/kg) to large seconds (28/kg), an increase of 59% in 9 months. The minimum mortality was 52%. Fouling growths of barnacles, tunicates, sponges and hydroids were restricted by placing experimental trays on top of the raft for several days to dry out. Compared with controls, this resulted in increased oyster growth in experimental trays during the next 6 months. Oyster mortality and incidence of mudworm blisters (resulting from the polychaete Polydora websteri) were similar in both control and experimental trays during this period. For improved growth of trayed submerged oysters the optimum vertical distance between trays and the optimum density of oysters on trays need to be determined.     

潮间带潜堤网栏养虾设施的设计

在近岸潮间带建设潜堤,并在堤顶设置拦网是一种新型的对虾人工养殖设施。这种潜堤网拦养殖设施,在涨潮时,海水越堤而过,注入池内;退潮时,利用拦网防逃,潜堤贮水,实现自行换水。该设施投资小,节省能源,管理方便,产量高。本文通过两个已建工程的设计,说明这种养殖设施的可行性,并提出潜堤和拦网设计中的各项参数的确定方法。     

Short communication: adaptability of the feeding behavior of intertidal ribbed mussels (Geukensia demissa) to constant submersion

The ribbed mussel (Geukensia demissa, Dillwyn 1817) is a dominant benthic filter-feeder in salt marshes along the North American Atlantic Coast. It has been proposed that the cultivation and harvest of ribbed mussels could be used to bioremediate the eutrophication of coastal waters. To accomplish this, mussels would be grown in suspension culture underwater, which is different than this species’ natural, intertidal habitat in which they are exposed to a tidal regime of submersion and emersion. To assess possible effects of constant submersion upon the feeding behavior of G. demissa, we quantified filter-feeding activities of ribbed mussels collected from either an intertidal location or a permanently submerged (2 months) population in the same embayment. Filtration measurements to determine clearance rates were conducted in aquaria containing ultra-filtered seawater with cultured phytoplankton. Results show that mussels taken from the intertidal population had significantly higher filtration than the submerged population initially, but after 3 days of submersion in the aquaria, this difference disappeared. Moreover, all experimental G. demissa had higher clearance rates during natural low tide than during natural high tide. These results indicate a potential for ribbed mussels to be grown in suspension culture for nutrient bioextraction purposes.     

The Effects of Tidal and Bottom Placement on the Growth, Survival and Fouling of the Eastern Oyster Crassostrea virginica

Oysters Crassostrea virginica in Georgia are naturally small and grow in clusters; however, it is more profitable to harvest large, single oysters. This study attempts to identify favorable tidal and bottom placements for the grow-out of large, single oysters in Georgia. Three bags, each containing 50 single oysters, were placed in four different tidal positions (subtidal on-bottom, subtidal off-bottom, intertidal on-bottom and intertidal off-bottom) at five sites in House Creek, Georgia. Measurements of oyster growth, survival and degree of oyster spat fouling were taken seasonally (every 3 mo). Oysters from on-bottom treatments exhibited significantly lower growth ( P = 0.0364 intertidal only), survival ( P = 0.0044) and degree of fouling ( P = 0.0154) than oysters from the intertidal off-bottom treatment. However, the oysters placed intertidally off-bottom were heavily fouled during the recruitment period. It may be necessary to sacrifice some growth and survival by culturing oysters intertidally on-bottom during the recruitment period in order to reduce the degree of fouling. During the non-recruitment period, placing oyster culture bags intertidally off-bottom maximizes growth and survival.     

Habitat use of globally threatened juvenile Chinese horseshoe crab,Tachypleus tridentatus under the influence of simulated intertidal oyster culture structures in Hong Kong

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