A study on the polyculture of the algae, the shrimp and the crab

A study was made on the polyculture of the red algae Gracilaria tenuistipitata Chang et Xia f. Liui Zhang et Xia, f. nov. , the shrimp Penaeus penicillatus Alcock and the mud crab Scylla serrata (Forskal) . The photosynthesis of the algae produces the oxygen on which the shrimp and the crab breathe. The algae are the reproductive place of the organism for the food of the shrimp and the carb, also is the shelter of the shrimp and the crab. The shrimp and the crab regard the algae as the vegetable     

锯缘青蟹幼体饵料蛋白质的营养价值评价

本文分析测定了锯缘青蟹幼体从刚孵化至大眼幼体各发育阶段及其饵料轮虫和卤虫无节幼体的氨基酸组成，并使用必需氨基酸指数(EAAI)来评价饵料蛋白质的质量.结果表明，青蟹各期幼体的氨基酸组成基本趋于一致，且与饵料转换不存在明显的相关性.对于各期幼体，饵料轮虫和卤虫无节幼体的必需氨基酸指数均大于90，可以认为，轮虫和卤虫无节幼体能够满足锯缘青蟹幼体对饵料中必需氨基酸的营养需求.     

Seasonal abundance, distribution and recruitment of mud crabs (Scylla spp.) in replanted mangroves

The abundance and distribution of mud crabs were studied in a replanted mangrove forest in Buswang, Aklan, Philippines. Two fishing gears, lift nets and bamboo traps, were used to monitor relative abundance of Scylla spp. populations from March 2002 to December 2003 inside the mangrove forest. A third gear, a stakenet set across a creek, was used to monitor crabs migrating out of the mangroves during the ebb tide. Scylla olivacea formed 99.3% and 70.3% of the catch in the mangrove and the stakenet, respectively. The percentage of Scylla tranquebarica increased from <1% in the mangrove catches to 29% in the stakenet. Scylla serrata was present at very low levels in both catches. The lack of modal progression in the size–frequency plots and the year-round catch rate of gravid females suggested that recruitment was constant throughout the year. Even though relative abundance decreased over the study period indicating that the stock is being over-exploited, mud crab production is more than equivalent to that of most natural mangroves.     

Trends in exploitation, development and management of artisanal mud crab (Scylla serrata-Forsskal-1775) fishery and small-scale culture in Kenya: An overview

Mud crab (Scylla serrata) is a delicacy for subsistence consumption in fisher communities and tourist hotels in the coast of Kenya while export demand to markets in China and Japan is expanding and provides competitively higher prices. Crab exploitation and degradation of the mangrove forests have increased over the last decades therefore threatening the capture fishery. The preferred market size crab has consistently decreased from more than 1 kg two decades ago to the current size of 0.5 kg therefore posing both management and livelihood threat to the critical ecosystem (mangrove) and coastal populations. To meet the increased tourist and export demand and provide surplus for the local community while conserving the critical crab ecosystem, small-scale aquaculture has been initiated in the concept of silvofisheries. Initial culture methods have targeted sub-adult crabs of 150–350 g for culture to market size (>0.5 kg) in drive-in cages and pens (mud crab fattening). These technology attained survival of between 50 and 70% and a market price of 5 dollars per kilogram. However, research is ongoing to assess viability of stocking juvenile seed crabs directly in ponds as practised in South East Asia (SEA) as opposed to stocking of sub-adults in drive-in cages. In comparison with other areas, crab capture fisheries in East Africa have limited management and enforcement frameworks/capabilities within the wider regional fisheries policies. Also there is limited understanding of wild mud crab resources and suitable management options to avoid over-exploitation as observed in SEA. The double-edged demand (wild market size capture and juvenile capture for aquaculture) for mud crabs in addition to mangrove degradation are likely to cause great challenges to stock exploitation and livelihoods of the coastal people dependent on the resource. This review paper provides an inside onto the tradition, trends and options for development of mud crab capture and culture in Kenya.     

Toxic effects of certain heavy metals (Hg,Cd, Pb,As and Se) on the intertidal crab scylla serrata

The toxic effects of certain heavy metals (Hg, Cd, Se, As and Pb) on Scylla serrata, the common edible Indian marine crab, are evaluated. Mercuric chloride, phenyl mercuric acetate (PMA), cadmium chloride, selenium dioxide, arsenic trioxide and lead nitrate were tested individually in laboratory static bioassays using artificial seawater to determine the 24 to 96 h LC₅₀ values. As indicated by 96 h LC₅₀ values PMA was found to be the most toxic and lead nitrate the least toxic. CdCl₂ showed a 6·6 fold increase in toxicity with increase in the time of exposure from 24 to 96 h. Marked histopathological changes were noticed in the hepatopancreas and gill of Scylla serrata exposed to acute 96 h LC₅₀ values of these metal compounds. 30 days' long-term exposure to sublethal concentrations of mercury and cadmium brought about degenerative changes in the hepatopancreas and gill of exposed animals. Extensive cellular proliferation (hyperplasia) of secondary lamellae accompanied by cyst formation and necrotic regions were often seen in the gills of cadmium treated crabs. Interestingly enough, the free amino acid pool from muscle and hepatopancreas of treated animals, either after acute or long-term exposure, did not show any reduction in number or quantity     

水产品主要过敏原的模拟胃液消化实验的条件优化

采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和免疫印迹（Western blot）方法,通过体外模拟消化实验分析水产品主要过敏原原肌球蛋白（Tropomyosin,TM）和小清蛋白（Parvalbumin,PV）的消化特性,主要研究酶/蛋白的比值、pH值对模拟胃液（SGF）消化过敏蛋白稳定性的影响。结果表...     

Fishery characteristics and abundance estimates of the mangrove crab Scylla serrata in southern Tanzania and northern Moçambique

The mud crab Scylla serrata is lightly exploited along the East African seaboard. This study reports on fishing practices and gives preliminary estimates of abundance and size structures of the mud crab populations in Utende, Chole Island and Juani Island, Tanzania, and west of Quirimba and Ibo Island, Moçambique. Estimates for three mangrove habitats (in Tanzania); open channel (<1 per 25 m²), mangrove fringe (3 per 25 m²) and inner forest (1 per 25 m²) were obtained using burrow density and from burrow occupancy from fisheries data. Mud crabs from Tanzania were significantly smaller (carapace width) and less abundant (in terms of mass) than those from Moçambique. This newly exploited resource provides a potential alternative source of income, but local management and monitoring plans need to be implemented early.     

Phylogeography of the mud crab (Scylla serrata) in the Indo‐West Pacific reappraised from mitochondrial molecular and oceanographic clues: transoceanic dispersal and coastal sequential colonization

The widespread mud crab, Scylla serrata, of the Indo‐West Pacific is an excellent model species to demonstrate how the colonization history of a species can be influenced by complex oceanographic conditions. Through the combination of ecological data (fossil records and paleo‐oceanographic conditions) and molecular data (coalescent simulations, network analysis, and nucleotide diversity tests), the phylogeographic history of S. serrata was re‐analyzed. Based on the analysis of mtDNA cytochrome oxidase I sequences, two major clades were identified for S. serrata, including a widespread clade (Clade I) with three disjunct geographic clusters (IA, IB and IC) and an endemic Northwest Australian clade (Clade II). Moreover, a significant phylogeographic structure corresponding to four subpopulations was revealed: Northwest Australia, West Indian Ocean, Red Sea‐South China Sea and West Pacific. A colonization history of a Northwest Australia origin for S. serrata followed by westward transmarine dispersal across the Indian Ocean for Clade I and sequential colonization from the West Indian Ocean to Red Sea‐South China Sea and West Pacific was corroborated. The Pleistocene fluctuations of paleo‐oceanographic conditions including surface circulations and physical topography in the Indo‐West Pacific might be responsible for the wide distribution, colonization history and genetic divergence of this species.     

Cannibalistic interactions of juvenile mud crabs Scylla serrata: the effect of shelter and crab size

In the culture of mud crab Scylla serrata, cannibalism is often the greatest cause of mortality. A laboratory study was conducted to compare the influence of size class differences and shelter on cannibalism and limb loss in juvenile mud crabs (20–70 mm internal carapace width; ICW). Four size classes of juvenile crab (A: 21–30 mm, B: 31–40 mm, C: 41–50 mm and D: 51–70 mm ICW) were tested in all possible combinations using four different substrata with varying degree of shelter (seaweed, plastic strings, bamboo tubes and open sand substratum) in 48 h trials. Results suggest that cannibalistic interactions are heavily influenced both by size differences of crabs and the availability of shelter. Cannibalism on the smallest size class (20–30 mm ICW) increased about 10 times in the presence of the largest crab (51–70 mm ICW) compared with treatment with only same-size crabs (control treatment). Shelter provided little refuge for the smallest crabs, whereas cannibalism in larger size classes decreased by >50% in all the shelters compared with the sand substratum. The findings suggest that both size-grading and provision of shelter could minimise cannibalism in the culture of mud crabs.     

锯缘青蟹碱性磷酸酶分离纯化及部分理化性质研究

于１９９５年２月在厦门海域采集锯缘青蟹,取其内脏经正丁醇抽提,硫酸铵分级分离ＤＥＡＥ－５２离子交换柱层析及ＳｅｐｈａｄｅｘＧ－２００凝胶过滤柱层析纯化,获得碱性磷酸酶 制剂,以快速 蛋白液相色谱及聚丙烯酰胺凝胶电泳检验萁 纯度,获得单一蛋白纯的酶 制剂。     

An improved electrochemical method for the quantification of metallothioneins in marine organisms

A six-to nine-fold increase in detection limits of the Brdic?ka polarographic assay for metallothioneins has been achieved through the employment of a commercially available static mercury drop electrode (SMDE) and reduced temperatures. At 16°C detectable concentrations of metallothionein (MT-1) from the crab Scylla serrata were in the range of 5 to 10 μg litre^-1. Operating conditions and electrode preparation are discussed. For a number of thiolic molecules a linear relationship between polarographic response and either the number of cysteinyl residues or the molecular weight was noted. In the latter case on enhancement of response by sulfur-metal bonds is suggested. The utility of this assay permits a rapid quantitative assay for these proteins at basal levels in marine invertebrates and other organisms.     

锯缘青蟹幼体性分化的解剖学及组织学实验研究

锯缘青蟹（Ｓｃｙｌｌａ ｓｅｒｒａｔａ［Ｆｏｒｓｋａｌ］）背甲宽×长为２．３×１．５ｃｍ的幼蟹，其上部性征已开始发生分化，雌性个体腹部宽度增大，副性征也有胆显的差异，在雄性个体腹足呈单肢型而雌体呈双肢型。但是，在幼蟹生殖腺仍见不到组织学上的差异。腹部肢是分辨幼蟹性别是为直观，适宜的指标。本文还讨论了青蟹两性生殖系统形态结构及其功能上的差异问题。     

饵料对锯缘青蟹大眼幼体生长发育的影响

以不同比例的轮虫和卤虫无节幼体搭配成各种饵料组合，分别喂养不同发育期的锯缘青蟹幼体，重点研究大眼幼体的存活、生长发育、变态和干重及化学元素(C、H、N)含量的情况.结果表明饵料搭配得当，适时适量的投喂，其幼体的生长发育和变态都正常，并可获得较高的存活率，若饵料搭配不当不仅会导致幼体出现高死亡率，而且还能诱发发育期变化的现象；不同饵料搭配对大眼幼体干重及化学元素(C、H、N)含量的影响很显著，相差60％～70％，约一个发育期，而这差异可以通过该期幼体投喂足量卤虫无节幼体来加以弥补，大眼幼体的C、H、N占干重的百分比仅次于溞V，这表明青蟹幼体在这两次变态前需在体内积累高比例的有机营养物质来保证变态的顺利进行.     

环境因素诱发锯缘青蟹幼体发育期变化的研究

首次报道了锯缘青蟹幼体发育期的变化现象，即：蚤状幼体阶段多了１个发育期（正常５个，异常６个）。发育期的变化与环境因素有关。     

四种不同饵料对真蛸(Octopus vulgaris)生长与肠道微生物影响的研究

本研究分析了不同饵料对真蛸(Octopus vulgaris)生长与肠道微生物的影响。实验采用4种饵料:蓝点马鲛(鱼组)、天津厚蟹(蟹组)、四角蛤蜊(贝组)和日本枪乌贼(鱿鱼组)分别投喂真蛸,分析了各实验组真蛸的日均摄食量、特定生长率、饵料转化率、经济效益比,以及饵料对肠道微生物菌群结构和多样性的影响。实验结果表明:在生长性能指标方面,贝组的日均摄食量最高,而饵料转化率低于鱼组与蟹组;鱼组与蟹组的日均摄食量差异不大,但蟹组真蛸的特定生长率和饵料转化率高于其他三组且经济效益最佳;鱿鱼组的日均摄食量、特定生长率、饵料转化率和经济效益比均低于其他三组。在真蛸肠道微生物群落的丰富度与多样性方面,鱼组均高于其他各组,而鱿鱼组的丰富度最低;在门水平上,软壁菌门、螺旋体门、变形菌门等10个门为真蛸的优势菌群;在属水平上,摄食率最大的贝组真蛸肠道菌群中的支原体、乳球菌等11种菌为优势菌群,特定生长率最大的蟹组中真蛸肠道菌群中的弧菌、小纺锤状菌等5种菌为优势菌群。综合不同饵料对真蛸生长性能指标和肠道菌群的影响,认为蟹类是真蛸理想的饵料。     

锯缘青蟹秋苗土池越冬的试验研究

本文报道１９９３和１９９４年秋季作者培育的部分锯缘青蟹仔蟹苗土池越冬试验。结果表明人工培育的青蟹苗在闽南地区的自然条件下,可以在室外土池完全越科,成活率可达６０－８０％,水温是影响青蟹生命活动的主要因素;由于越冬期间青蟹营养积累不足,导致难以顺利地完成越冬后的第一次生长蜕壳,造成大量死亡,这是影响青蟹越冬存活率的主要因素之一;越科后期病死青蟹肝胰组织进行涂片处理,发现６只受检蟹中２只肝胰组织中有日     

High environmental salinity reduces the reproductive potential of the spider crab Maja brachydactyla (Decapoda,Majidae)

The spider crab Maja brachydactyla is an important fisheries species in Europe. Adults were sampled in Ría de A Coruña (NW Spain) and transported to IRTA rearing facilities. Salinity and photoperiod changes and their effect on reproduction were tested in the laboratory. The number of newly hatched larvae per batch (presence of actively swimming newly hatched larvae in a broodstock tank) was counted and sampled to estimate dry weight and proximal composition. Keeping spider crab broodstock in a high salinity environment (38 ppt) significantly reduced the number of newly hatched larvae, reaching up to fivefold difference in winter. The number of newly hatched larvae produced under a natural photoperiod was 10‐fold higher than those produced using a fixed photoperiod at 34 ppt salinity during winter. No clear pattern of changes in larval dry weight, protein, lipid or carbohydrate composition was observed under the environmental conditions tested. The results show that the salinity used for broodstock maintenance, especially during the embryonic development, is an important factor causing changes in larval production of M. brachydactyla and with potential implications for recruitment success.     

几种虾蛄生物学特性和繁殖生物学研究进展

虾蛄(Squillidae)是重要的水产增养殖品种。目前针对虾蛄类的研究主要集中在其基础生物学和繁殖生物学方面,其中在虾蛄的纳精结构、性腺发育和幼体发育等研究方面还存在诸多分歧。作者综述了几种虾蛄类,如口虾蛄(Oratosquilla oratoria)、黑斑口虾蛄(O. kempi)、猛虾蛄(Harpiosquilla harpax)和棘突猛虾蛄(H. raphidea)的资源分布、生活习性、亲本、性腺和幼体发育等研究成果,以期为虾蛄繁殖生物学和人工育苗的深入研究提供参考。     

Recruitment variation of eastern Bering Sea crabs: Climate-forcing or top-down effects?

During the last three decades, population abundances of eastern Bering Sea (EBS) crab stocks fluctuated greatly, driven by highly variable recruitment. In recent years, abundances of these stocks have been very low compared to historical levels. This study aims to understand recruitment variation of six stocks of red king (Paralithodes camtschaticus), blue king (P. platypus), Tanner (Chionoecetes bairdi), and snow (C. opilio) crabs in the EBS. Most crab recruitment time series are not significantly correlated with each other. Spatial distributions of three broadly distributed crab stocks (EBS snow and Tanner crabs and Bristol Bay red king crab) have changed considerably over time, possibly related in part to the regime shift in climate and physical oceanography in 1976–1977. Three climate-forcing hypotheses on larval survival have been proposed to explain crab recruitment variation of Bristol Bay red king crab and EBS Tanner and snow crabs. Some empirical evidence supports speculation that groundfish predation may play an important role in crab recruitment success in the EBS. However, spatial dynamics in the geographic distributions of groundfish and crabs over time make it difficult to relate crab recruitment strength to groundfish biomass. Comprehensive field and spatially explicit modeling studies are needed to test the hypotheses and better understand the relative importance and compound effects of bottom-up and top-down controls on crab recruitment.     

锯缘青蟹(Scylla serrata)幼体胃磨发育的比较研究

在青蟹幼体发育过程中，胃磨呈现出明显的变化。Ｚ１缺乏胃磨的结构，ＺⅡ开始出现中齿和侧齿的雏形，明显的可以识别的中齿和侧齿出现在ＺⅢ，．从ＺＶ开始胃磨已臻完善，除具有中齿和侧齿外，还出现了４个附属齿，包括两个附属的中齿和两个附属的侧齿。大眼幼体期，中齿和侧齿比ＺＶ更加尖锐，附属齿也更加锋利。在仔蟹前，中齿齿尖发生特化，形成垫状角质化区域，侧齿、附属齿更加锋利。这表明青蟹幼体发育过程中胃磨结构的变化与