Effects of different dietary lipid sources on growth performance and tissue fatty acid composition of juvenile swimming crab Portunus trituberculatus

This study was conducted to evaluate the effects of dietary lipid sources on the growth performance and fatty acid composition of the swimming crab, P ortunus trituberculatus. Four isonitrogenous and isoenergetic experimental diets were formulated to contain four separate lipid sources, including fish, soybean, rapeseed, and linseed oils(FO, SO, RO, and LO, respectively). With three replicates of 18 crabs each for each diet, crabs(initial body weight, 17.00 ±0.09 g) were fed twice daily for 8 weeks. There were no significant differences among these groups in terms of weight gain, specific growth rate, and hepatosomatic index. However, the RO groups' survival rate was significantly lower than FO groups. The feed conversion and protein efficiency ratios of RO groups were poorer than other groups. The proximate compositions of whole body and hepatopancreas were significantly affected by these dietary treatments. Tissue fatty acid composition mainly reflected dietary fatty acid compositions. Crabs fed FO diets exhibited significantly higher arachidonic, eicosapentaenoic, and docosahexaenoic acid contents in muscle and hepatopancreas compared with VO crabs. Linoleic, oleic, and linolenic acids in muscle and hepatopancreas were the highest in the SO, RO, and LO groups, respectively. The present study suggested that SO and LO could substitute for FO in fishmeal-based diets for swimming crabs, without affecting growth performance and survival.

Implementing geostatistical analysis to study spatio-temporal distribution patterns of swimming crabs(Portunus trituberculatus)

This study attempted to compare the performance of local polynomial interpolation,inverse distance weighted interpolation,and ordinary kriging in studying distribution patterns of swimming crabs.Cross-validation was used to select the optimum method to get distribution results,and kriging was used for making spatial variability analysis.Data were collected from 87 sampling stations in November of 2015(autumn)and February(winter),May(spring)and August(summer)of 2016.Results indicate that swimming crabs widely distributed in autumn and summer:in the summer,they were more spatially independent,and resources in each sampling station varied a lot;in the winter and spring,the abundance of crabs was much lower,but the individual crab size was bigger,and they showed the patchy and more concentrative distribution pattern,which means they were more spatially dependent.Distribution patterns were in accordance with ecological migration features of swimming crabs,which were affected by the changing marine environment.This study could infer that it is applicable to study crab fishery or even other crustacean species using geostatistical analysis.It not only helps practitioners have a better understanding of how swimming crabs migrate from season to season,but also assists researchers in carrying out a more comprehensive assessment of the fishery.Therefore,it may facilitate advancing the implementation in the pilot quota management program of swimming crabs in northern Zhejiang fishing grounds.

Music stimulus has a positive eff ect on survival and development of the larvae in swimming crab Portunus trituberculatus

The sound stimulus has a signifi cant impact on marine animals.However,many studies have focused on the negative impacts of sound on marine vertebrates.The positive impacts of sound on marine animals,especially on marine invertebrates,were rarely studied.In the present study,we evaluated the eff ects of music on the survival and development of an economically important marine invertebrate,swimming crab Portunus trituberculatus.Three pieces of classical music and a control group,i.e.,Eine Kleine Nachtmusik by Mozart(EK),Bach-Violin Concerto No.1(BV),Anonymous Romanza by Anonymous(AR),and environmental sound(EN)were used.The sound pressure received were 163-dB root mean square(RMS)re 1μPa for EK,166-dB RMS re 1μPa for BV,165-dB RMS re 1μPa for AR,44-dB RMS re 1μPa for EN,respectively.The larvae were subject to 3-h classical music transmission every day during the entire larval development period.The result showed that BV and AR signifi cantly elevated the cumulative survival rate of the larva from 3.42%±1.77%(EN)to 10.65%±1.69%(BV)and 7.12%±1.37%(AR)respectively(P<0.05).Though music did not aff ect the cumulative development time of larvae from ZoeaⅠto ZoeaⅣ,it signifi cantly increased the molting rate of megalopa from 24.00%±11.78%(EN)to 44.00%±13.06%(AR)and 46.67%±10.50%(BV)(P<0.05).Musical exposure during critical growth intervals may contribute to the survival and development of larval crustaceans.From an application point of view,music intervention is much economically feasible.The observed music eff ects imply that music could further enhance growth,welfare,and production.

Long-term in-vitro culture and subculture of the hemocytes of swimming crab Portunus trituberculatus

Crab cell line,especially continuous crab cell line,can provide us a useful tool for studies on the virology,immunology,and molecular biology of crabs.However,no continuous crab cell line has been available due to the lacking of suitable medium and the occurrence of mitosis-arrest.In this study,long-term in vitro culture conditions for both two-(2D)and three-dimensions(3D)were successfully developed for the circulating hemocytes of swimming crab Portunus trituberculatus,designated as PTH cells.In 2D culture,a novel crab basic medium in osmolarity of 990–1100 mOsm/kg was optimized for the first time,which is different from Leibovitz's L-15 medium in mainly the components of amino acids,containing double strengths of the contents of free amino acid mixture in the crab serum.Then an optimal crab growth medium was developed by supplementing 5%fetal bovine serum,50-g/L yeast extract powder,20-μg/L basic fibroblast growth factor and epidermal growth factor into the optimal crab basic medium,and found that it could support a long-term survival of PTH cells in a healthy monolayer up to 347 days and partially break through the mitosis-arrest of crab cells evidenced by the obvious increase of proliferating potential detected in the 10-d primarily cultured PTH cells.These 2D cultured PTH cells could be successfully sub-cultured for 11 times by physical flushing method and well cryopreserved in liquid nitrogen.In 3D culture,using the same crab growth medium,the PTH cell aggregates could be easily formed and healthily maintained on the surface of solidified Matrigel or in the ultra-low-attachment plate with a survival rate of 50%–60%on Day 103.This work largely improved the primary culture and subculture of crab cells and will facilitate the establishment of continuous crab cell line.

水溶氧对三疣梭子蟹(crab Portunus trituberculatus,Miers,1876)生理应答的影响(英文)

本研究旨在探究不同水溶氧水平对三疣梭子蟹生理应答的影响。将50只成体三疣梭子蟹（CrabPortunus trituberculatus）分别饲养在不同水溶氧水平（1、2、4、8、12 mg/L）的密封水槽中,10 d后测定其耗氧率,同时比较血液中蛋白质、氧合血蓝蛋白、血细胞含量;测定消化腺代谢产物（糖原、蛋白质、葡萄糖、胆固醇、酰基甘油、乳酸）含量;比较消化酶活性及乳酸脱氢酶活性的差异。结果显示：三疣梭子蟹生存关键的溶氧水平为2~4 mg/L;血液中蛋白质和氧合血蓝蛋白含量与耗氧率一致;消化腺代谢产物糖原和蛋白质含量不随溶氧水平的变化而变化（P〉0.05）,但葡萄糖、胆固醇和酰基甘油含量随溶氧水平降低而呈直线下降;水溶氧对消化酶活性影响不大（P〉0.05）,但乳酸脱氢酶活性和乳酸含量却随溶氧水平降低而显著增加（P〈0.05）;较低的水溶氧还通过明显降低血细胞含量（P〈0.05）来影响三疣梭子蟹的免疫功能。研究表明：三疣梭子蟹可通过改变血液中氧合血蓝蛋白含量、某些消化腺代谢产物含量以及厌氧呼吸等生理机制来适应较低的水溶氧生态环境。

Impacts of sampling design on the abundance estimation of Portunus trituberculatus using crab pots

Fishery-independent surveys can provide high-quality data and support fishery assessment and management.Optimization of sampling design is crucial to increase the quality of fishery surveys.Crab pots are important fishing gears used to catch crabs.We analyzed the impacts of sampling design of crab pots on the abundance of Portunus trituberculatus in the Changjiang(Yangtze)River estuary to the Hangzhou Bay and its adjacent waters in East China Sea.The crab pots were cylindrical,240 mm in height and 600 mm in diameter of the iron ring.Our sampling designs(including fixed-station sampling,simple random sampling,stratified fixed-station sampling,and stratified random sampling),three number of stations(9,16,and 24),and three numbers of crab pots(500,1000,and 3000)were simulated and compared with the“true”abundance that obtained from bottom trawl surveys in the study area in 2007.The scenarios with 16 stations were set in stratification as a control group for comparison with unstratified designs.Results show that simple random sampling can obtain more stable results than fixed-station sampling in the abundance estimation of P.trituberculatus.In addition,stratified sampling resulted in more accurate abundance than unstratified sampling.The accuracy of the simulated results improved with the increase of the number of stations.No remarkable differences in the results were found among the scenarios of different number of crab pots at each station.However,resource-intensive areas exerted great impacts on simulation results.Thus,prior information or pre-survey results about resource abundance and density distribution are necessary.This study may serve as a reference for future sampling designs of crab pots of P.trituberculatus and other species.

三疣梭子蟹(Portunus trituberculatus)幼蟹饲料中胆固醇的适宜添加量研究

采用单因素实验设计方法,以初始体重为20g左右的三疣梭子蟹(Portunus trituberculatus)幼蟹为实验对象,胆固醇添加量为0.003%、0.3339%、0.655%、0.986%、1.303%和1.628%的实验饲料投喂8周,研究其胆固醇需求量。结果表明,饲料中添加0.003%—1.628%胆固醇对各处理组的存活率无显著性影响(P>0.05)。随饲料胆固醇水平的上升,三疣梭子蟹幼蟹的增重率呈先上升后下降的趋势,当饲料胆固醇水平≥0.655%时,三疣梭子蟹幼蟹的增重率呈下降趋势。折线模型表明,饲料中胆固醇添加量为0.6%时,三疣梭子蟹幼蟹的增重率、性腺指数和壳宽增加达到最高值。根据增重率折线模型结果,作者认为三疣梭子蟹幼蟹饲料中添加0.6%左右胆固醇较为适宜。

虾蟹混养塘中WSSV对三疣梭子蟹(Portunus trituberculatus)致死效应的定量研究

采用实时荧光定量PCR法,在对白斑综合症多发的虾蟹混养塘内三疣梭子蟹体内病毒含量进行定量跟踪检测的基础上,结合电子显微镜及病理切片,对室内经口服、注射两种回感模式处理已感染白斑综合症病毒的濒死三疣梭子蟹体内病毒含量进行实验验证,并观察其体内主要器官组织的病理改变。结果表明,受白斑综合症病毒感染的三疣梭子蟹存活与死亡取决于蟹体内病毒含量,当病毒含量≥109拷贝/ml时均进入濒死或死亡阶段,其主要器官组织均有明显的病理改变。

砂粒粒径与砂层厚度对单体筐养养殖系统中三疣梭子蟹(Portunus trituberculatus)幼蟹摄食行为与生长特性的影响研究

在三疣梭子蟹(Portunus trituberculatus)的单体筐养养殖系统中,试验了生态掩体(砂盒)中不同的砂粒粒径大小以及砂层厚度对梭子蟹幼蟹摄食行为与生长特性的影响。砂粒粒径设三个水平,分别为:>2mm、<0.2mm以及混合砂;砂层厚度有0cm、2cm、5cm、8cm四个水平。试验共进行6天,结果表明:砂粒粒径及砂层厚度对梭子蟹幼蟹的摄食与生长都有明显的影响。从砂粒粒径看,幼蟹在细砂(SPS)中挖洞休息,蟹体与砂面呈30—45°角,仅露眼睛及触角在外。一天内有3—6次进食,总进食时间为(142.7±22.52)min,在摄食次数、总进食时间、平均摄食量[(0.2427±0.0137)g/g BW]、以及蜕皮及成活率都远高于其它粒径组,该组中幼蟹的体重增长最快,增加了(0.814±0.113)g,增长率为91.5%±3.43%;而该组的饵料系数(FCR)最低为1.17±0.11。因此,筐养养殖系统砂掩体的砂粒粒径最好为0.2 mm以下。砂层厚度也有类似结果,5 cm以上厚度养殖效果最佳。平均摄食量为(0.2087±0.0046)g/g BW,该厚度下,幼蟹无死亡、100%蜕皮,体重也增加最快,增加了(0.791±0.121)g,增长率为88.9%±3.74%,饵料系数(FCR)达到1.37±0.23,表明筐养系统掩体中砂层厚度要在5 cm以上。三种保护性酶类(SOD,POD,CAT)活性随着砂粒粒径变小和砂层厚度增加而降低,而消化酶类(淀粉酶、蛋白酶、脂酶)活性则表现与保护性酶类相反特性。从两类酶的活性变化也能证实,在优选条件下(细砂、厚度>5 cm),幼蟹所受的胁迫在降低。

饲料n-3 HUFA水平对三疣梭子蟹(Portunus trituberculatus)幼蟹生长、饲料利用和组织脂肪酸组成影响的研究

以白鱼粉和酪蛋白为蛋白源,通过调节EPA和DHA高浓度油来配制四组等氮（42.00%~44.10%）、等能（18.26~18.67 k J/g）含有4种不同n-3高不饱和脂肪酸（n-3 HUFA）水平（0.52%、1.12%、2.33%和4.02%）的试验饲料,每组饲料设3个平行,每个平行15只螃蟹,进行为期8周的摄食生长实验。实验结果表明,饲料中不同n-3 HUFA水平影响了三疣梭子蟹的增重率,2.33%组显著高于0.52%组和4.02%组（P〈0.05）。随着实验饲料中n-3 HUFA水平的上升,饵料系数（FCR）呈现出先下降后上升的趋势,最低值出现在2.33%组,为1.02±0.11,显著低于0.52%组和4.02%组（P〈0.05）。肝体比（HSI）随着实验饲料中n-3 HUFA水平的上升而下降,其中4.02%组显著低于0.52%组（P〈0.05）。三疣梭子蟹肌肉和肝胰腺的脂肪酸组成明显受到了饲料脂肪酸组成的影响,肌肉和肝胰腺脂肪酸中n-3 HUFA含量与饲料脂肪酸中n-3 HUFA含量呈现正相关关系。综合饲料n-3 HUFA含量对其生长和饲料利用的影响,再结合生长的折线模型,估算出三疣梭子蟹配合饲料中n-3 HUFA的适宜添加量为2.36%。

饲养空间大小对单体筐养养殖系统中三疣梭子蟹(Portunus trituberculatus)的摄食行为与生长特性的影响研究

在三疣梭子蟹(Portunus trituberculatus)的单体筐养养殖(SCBC)系统中,研究了不同的饲养空间大小对梭子蟹(幼蟹与成蟹)摄食行为与生长的影响。试验设置了四个饲养空间处理:空间长度分别为养殖蟹平均壳长的1倍、1.5倍、2倍及3倍,宽为长的一半。经6天试验,结果表明,1倍空间的幼蟹摄食行为发生变化,摄食次数[(1.2±0.45)次/d]和总进食时间[(31.2±6.89)min]比2倍与3倍的空间[(2.6±0.45)次/d,(83.1±13.66)min]明显减少,导致摄食量减少[前者为(0.0835±0.0269)g/g BW,后两者最高为(0.2014±0.0114)g/g BW],至第5天全部死亡。其它处理,随着空间的增大,摄食量增大,幼蟹的生长速率(蜕皮率,体重增长率)增加。其中,在2倍空间以上处理中,幼蟹表现有最高的成活率(100%)、蜕皮率(100%)以及体重增长率(86.5%—97.2%),同时有较低的饵料系数(1.31±0.11)。成蟹的试验结果与幼蟹类似,除1.5倍饲养空间外,该处理中幼蟹表现出对生长的胁迫,而成蟹的摄食行为和生长与2倍及3倍空间无差异。不同空间中梭子蟹的摄食与生长的差异与梭子蟹在这些处理中的保护性酶类(SOD,POD,CAT)和消化酶类(淀粉酶,蛋白酶,脂酶)的活性有密切关系。

三疣梭子蟹(Portunus trituberculatus)耐低盐的遗传力估计

应用数量遗传学原理和全同胞组内相关法估计三疣梭子蟹(Portunus trituberculatus)Ⅱ期幼蟹和80日龄稚蟹耐低盐性状的遗传力。实验中采用梭子蟹室内人工控制定向交尾方法,构建了32个全同胞家系,包括9个半同胞家系。测定Ⅱ期幼蟹和80日龄稚蟹在盐度11胁迫下的存活率分别为55%和64%,差异显著。利用SPSS软件的一般线性模型(GLM),计算存活率变量的方差组分,估计耐低盐性状的遗传力。基于全同胞方差组分分析显示,全同胞方差组分估计的遗传力是对三疣梭子蟹两个发育阶段狭义遗传力的无偏估计值,Ⅱ期幼蟹耐低盐遗传力为0.18,属于低度遗传力;而80日龄稚蟹耐低盐遗传力为0.20,属于低度遗传力。因此,家系选育方法更适于三疣梭子蟹耐低盐新品种培育。

三疣梭子蟹(Portunus trituberculatus)肝胰腺内源酶性质的初步研究

内源酶是三疣梭子蟹(Portunus trituberculatus)体内重要的酶,往往会导致梭子蟹死后肌肉组织迅速软化,严重影响了蟹肉的贮藏品质。为了探明该酶的基本特性,本试验从三疣梭子蟹肝胰腺中提取了粗酶,优化了提取方法,并对其部分酶学性质进行初步研究。结果表明:三疣梭子蟹肝胰腺内源酶最佳浸提时间段为4～12 h,酶比活显著高于0～4 h和12～14 h;以酪蛋白为水解底物,内源酶作用最适温度为65℃、最适p H范围为7.0～8.0;丝氨酸蛋白酶特异性抑制剂,包括大豆胰蛋白酶抑制剂(SBTI)和苯甲基磺酰氟(PMSF),对内源酶活力的相对抑制率分别为100%、70.46%±6.27%,显著高于其他抑制剂的相对抑制率,推测丝氨酸蛋白酶为主要内源酶;在硫酸铵分级沉淀中,分别以酪蛋白和Boc-Phe-Ser-Arg-MCA为底物,前者最适盐析浓度为0～70%,后者为30%～70%,酶比活显著高于其他盐浓度;当硫酸铵浓度为40%～60%时,盐析蛋白质含量、粗酶酶活和丝氨酸蛋白酶活均显著高于其他盐浓度。

三疣梭子蟹(Portunustrituberculatus)冻藏过程中肌肉蛋白质生化特性的变化

以三疣梭子蟹肌肉基本营养成分、蛋白质组成、肌原纤维蛋白含量、Ca^(2+)-ATPase活性、总巯基含量、二硫键含量以及肌原纤维蛋白的SDS-PAGE分析作为指标,研究了三疣梭子蟹在不同冻藏温度下肌肉蛋白质生化特征的变化。结果表明,三疣梭子蟹是典型的高蛋白食品;随着冻藏时间的延长,水溶性蛋白含量先增加后减少,盐溶性蛋白和不溶性蛋白含量逐渐减少,碱溶性蛋白含量逐渐增加;肌原纤维蛋白含量、Ca^(2+)-ATPase活性、总巯基含量随着冻藏时间的延长,均呈现下降趋势,而二硫键含量则呈上升趋势,且–20℃和–40℃两组之间差异显著(P<0.05)。SDS-PAGE分析结果表明,组成肌原纤维蛋白的各种蛋白质均有不同程度降解,且–20℃比–40℃组降解更明显。因此,–40℃冻藏对梭子蟹肌肉蛋白质生化特性的影响较小。

Effect of escape vents on retention and size selectivity of crab pots for swimming crab Portunus trituberculatus in the East China Sea

An increase in the crab pot fishery in the East China Sea has caused great pressure on swimming crab Portunus trituberculatus resources.Thus,it is essential to implement suitable measures to release sublegal-sized crabs to increase the number of recruits for legal-sized crabs.One of the measures considered is the installation of escape vents on crab pots.We tested crab pots with one and two escape vents and compared the catchability and size selectivity of these pots with control pots without an escape vent.Pots with one escape vent located on single side of the pot,top or bottom(SS),and another on both sides at top and bottom edges(BS)were tested in sea trial experiments following typical commercial fishing practice.The results show that both SS pots and BS pots caught significantly smaller number of sublegal-sized crabs(<116 mm carapace width,CW),but the difference in catch between the two types of crab pots is not significant.The 50%selective CWs(CW_(50))and the selective ranges(SRs)of both BS pots are slightly larger than those of SS pots.However,95%confidence intervals of CW_(50)s and SRs are overlapped,indicating that the discrepancy between them is small.Then,in a mixed effect model,the effect of locations of escape vents,taken as the fixed effect,on selectivity parameters and indexes was analyzed by hypothesis testing.The results show that null hypothesis of no effect of location of vents on size selectivity cannot be rejected,indicating that there is no significant difference in size selectivity between the two types of pots for P.trituberculatus.

Effectiveness of escape vent shape in crab pots for releasing swimming crab Portunus trituberculatus in the East China sea

To stop the decline of swimming crab(Portunus trituberculatus)stocks in the East China Sea,escape vents on crab pots are urgently required to improve pot selectivity and enable release of sublegal-sized crabs.This study presents field comparative fishing experiments,which examined the effectiveness of different shapes and sizes of escape vents in crab pots for the release of swimming crabs.Two sizes each of rectangular,elliptic,and circular escape vents were tested.The results of comparative fishing experiments indicated that experimental pots with escape vents,regardless of their configuration,caught significantly fewer sublegal-sized crabs(<49 mm carapace length,or<116 mm carapace width)than unmodified control pots.Although legal-sized swimming crabs were also less caught,analysis of size selectivity showed that rectangular vents produced steeper selectivity curves than elliptic and circular escape vents.This indicates that rectangular vents may be more suitable and controllable when escape vents will become a requirement and their use will be enforced in fisheries.Underwater observations were conducted using GoPro cameras and LED lights during the first 2.5 h of the deployments(which usually lasted between 5 and 12 h).Video recordings of experimental pots equipped with rectangular or elliptic escape vents showed that swimming crabs trapped in the pots could detect the vents,and readily approached and passed through these.However,no significant difference was detected in the response behavior of swimming crabs between rectangular and elliptic vent pots when quantitative indicators,derived from video recordings,were compared.The effect of different vent shapes on the escape behavior of swimming crab gradually manifested as an increased soak time and by the onset of the escape of larger crabs.Future underwater observations should thus last the entire duration of pot soaking to study how crabs escape from the pots.

三疣梭子蟹精子顶体反应过程中的形态和结构变化

用离子载体A2 3187和卵水人工诱导三疣梭子蟹精子的顶体反应 ,分别获得 75 33%和 84 83%的顶体反应率。应用光镜和电镜技术观察了顶体反应前后精子形态和结构的变化。未处理精子呈陀螺形 ,由顶体、核杯和 5 - 10条核辐射臂组成。顶体包括顶体囊和顶体管。顶体囊的伞形头帽拥有约 70条辐射肋。连续发生的精子顶体反应过程被人为地分为四个阶段 :(1)头帽鼓起 ;(2 )顶体囊外翻 ;(3)穿孔器前伸 ,顶体囊膜翻转 ;(4 )顶体囊膜脱落 ,顶体丝形成。直到第四阶段才观察到钉状精子的辐射臂开始收缩。

不同温度养殖的雌体三疣梭子蟹性腺和蟹肉风味品质比较

研究常温养殖与加温养殖对雌体三疣梭子蟹性腺和蟹肉的风味影响,测定2组蟹性腺和肉中的主要滋味物质,并进行电子舌、电子鼻和感官评价的分析。结果表明:电子舌和电子鼻均可对不同水温养殖三疣梭子蟹的性腺以及蟹肉进行有效区分;加温养殖会提高鸟苷酸(guanosine monophosphate,GMP)和腺苷酸(adenosine monophosphate,AMP)对性腺滋味的贡献,使总游离氨基酸含量有所减少,呈味氨基酸和必需氨基酸百分比有所上升。对蟹肉而言,加温组GMP、肌苷酸、AMP相比常温组增加了0.40、0.66倍和3.46倍,呈味氨基酸、必需氨基酸和总游离氨基酸的含量显著升高(P<0.05),味精当量值与常温组相比增加0.59倍。感官评价表明,加温养殖组性腺的肥满度和气味评分有一定的提高,蟹肉的整体感官品质明显高于常温组。

蟹类精子超微结构的比较研究

应用光镜和电镜， 比较研究三疣梭子蟹（ Ｐｏｒｔｕｎｕｓｔｒｉｔｕｂｅｒｃｕｌａｔｕｓ） 、中华绒螯蟹（ Ｅｒｉｏｃｈｅｉｒｓｉｎｅｎｓｉｓ）和长江华溪蟹（Ｓｉｎｏｐｏｔａｍｏｎ ｙａｎｇｔｓｅｋｉｅｎｓｅ） 的成熟精子。揭示３ 种蟹精子都是不能游动的无鞭毛精子， 呈球形，前后略扁。精子前端出现一光滑的小圆面， 圆面四周有内陷的沟环。沟环之后， 精子表面凹凸不平， 并伸出多数辐射臂。３ 种蟹精子均为高度特化的细胞， 外被质膜， 内含细胞核、顶体及退化的细胞质。核前面内凹， 呈杯状， 因称核杯。核杯外被基本上连续完整的核膜； 染色质不浓缩， 呈细网状。核杯外侧的突出物形成辐射臂。顶体宛如落入核杯内的一个小球， 结构复杂， 外被顶体膜， 分为顶体囊、头帽和顶体管３ 部分。退化的细胞质分布于核杯和顶体之间， 内有膜复合体。另外， ３ 种蟹精子在超微结构上也存在一定的差异。

不同来源三疣梭子蟹池塘养殖的生长比较

2014和2015年,将试验池塘分隔成2000m2的单个池塘,分别养殖3种来源的三疣梭子蟹:自然海域捕获的越冬蟹经室内暂养(称越冬种群)、首次放流的Ⅱ期幼蟹(增殖种群)和自然海区第一批抱卵蟹繁殖的Ⅱ期幼蟹(自繁种群),研究了同生态条件下池塘养殖梭子蟹的存活和生长,为评估莱州湾海域三疣梭子蟹放流效果提供参考。2014年越冬、增殖和自繁3个种群幼蟹的放养时间依次间隔20d,以3个种群梭子蟹作为类轴,分别以全甲宽及体质量为x、y轴进行二维图相关分析。结果表明,在同步养殖10d、20d时,可以直观区分出3个种群梭子蟹;同步养殖30d,参照全甲宽和体质量指标,只能区分自繁种群与越冬种群;同步养殖40d,自繁和增殖种群全甲宽和体质量指标逐步接近越冬种群,无法对3个种群进行有效区分。自繁种群的成活率极显著高于增殖种群(P<0.01)。2015年,增殖和自繁两个种群同规格同步养殖15、30、45d和60d时,自繁种群平均全甲宽和平均体质量高于增殖种群,但差异不显著(P>0.05),不能以全甲宽和体质量指标鉴别种群,自繁种群的成活率亦极显著高于增殖种群(P<0.01)。本研究结果为梭子蟹增殖放流效果评价提供了参考。