菲律宾蛤仔苗种繁育技术研究

2005-2006年度,共利用800 kg亲贝进行了4批育苗,获得受精卵2.33×10^10粒,D形幼虫15734×10^10粒,平均孵化率68.8%。受精卵经22～25 d的培育,稚贝规格达210～296μm,2005、2006年度单位水体出苗量分别为1.315×10^6粒/m^3、2.797×10^6粒/m^3,出池稚贝的平均壳长分别为265μm、228μm。分别采用干露法和用常温阴干刺激加流水法进行催产,平均每千克亲贝所获得的受精卵、D形幼虫及孵化率前者分别是后者的33.5%、20.32%和60.6%。     

菲律宾蛤仔室内常温育苗技术

进行了室内常温条件下菲律宾蛤仔亲贝暂养催产，产卵孵化，幼虫培育试验，对试验结果进行了分析，并探讨了影响其性腺发育的因素和死亡高峰期的形成原因，对策。     

菲律宾蛤仔新品种研究进展

综合菲律宾蛤仔(Ruditapes philippenarum)新品种的最新研究进展,在育种目标、遗传育种、新品种、病虫害等方面进行综述,总结目前菲律宾蛤仔新品种面临的问题,展望新品种的未来发展。     

菲律宾蛤仔健康苗种培育设备

介绍了在菲律宾蛤仔健康苗种培育和高效养殖过程中(包括种贝培养、幼虫培育、稚贝中间育成和越冬)所使用的设施设备。这些设施设备的开发和使用,对降低劳动强度,提高养殖效率,节省能源发挥了重要作用,对其他滩涂贝类也有重要的示范意义。     

菲律宾蛤仔大规格育苗技术研究

我国北方菲律宾蛤仔养殖所需的蛤苗,都依赖从南方的福建、浙江、广西等省购进,运输路途遥远、蛤苗产量受气候、水文等条件影响丰欠不稳,运输时间长、成活率低等因素一直制约着菲律宾蛤仔养殖业的发展。为解决养殖苗种问题,2010-2011年,笔者进行了菲律宾蛤仔室内大规格苗种繁育,现将育苗技术报告如下:     

温度和盐度对菲律宾蛤仔稚贝生长及发育的影响

本文叙述了，在室内控制条件下，温度和盐度对菲律宾蛤仔稚贝生长及发育的影响。蛤仔稚贝生长的适宜水温为15—30℃，其中以25℃为最好。在此温度范围内，稚贝生长迅速，成活率高达80％以上。稚贝对10℃以下的低温有强的忍耐性，也能忍耐35℃的高温，其死亡的临界温度在40℃左右。稚贝生长的适宜盐度为14．0—33．5‰，最适盐度是20．5‰左右。在此盐度范围内，稚贝发育整齐，成活率高达85％以上。生长的盐度下限和上限分别为7．5‰和40．0‰左右。幼虫变态的适宜盐度在20．5～33．5‰之间，在此盐度范围内，幼虫成活率为65％以上。盐度在27‰时幼体的成活率最高，达到92．5％。幼虫变态的盐度下限为7．5‰左右，而上限则在于40．0—46．5‰之间。     

菲律宾蛤仔土池人工育苗试验报告

于１９９５年５～８月，利用对虾养殖土池乾地菲律宾蛤仔人工育苗试验，将２００亩土 池经清淤，铺沙等改造后使用。作了蛤仔的亲贝蓄养，诱导产卵，受精孵化和浮游幼虫培养，获得附着稚贝平均为２３１０万粒／亩，面盘幼虫至附着稚贝的成活率为１１．６％，试验结果表明，在北方地区用土池培育蛤仔种苗是可行的。     

菲律宾蛤仔苗种高密度培育技术

菲律宾蛤仔的苗种生产,经历了土池半人工采苗、土池全人工育苗,发展到今天的工厂化车间内全人工育苗。工厂化车间育苗极大地满足了养殖生产需要,幼体培育密度可达到150个／ml左右,最高可达到200个／ml,保苗成活率达30％以上,     

菲律宾蛤仔稚贝期不同培育密度对生长、成活率的影响

2001年～2002年在大连普兰店市进行了菲律宾蛤仔稚贝期在大水体培育条件下,培育密度为260万～400万枚/m2对稚贝的日生长速度、成活率的影响试验,2001年试验中总平均日生长速度为44 7μm,出苗量为12 168亿枚,成活率为85 4%;2002年试验中总平均日生长速度为39 2μm,出苗量为15 47亿枚,成活率为90 7%。试验表明,菲律宾哈仔稚贝培育密度为260万～400万枚/m2在实际生产中是可行的,对稚贝的日生长速度、成活率影响不显著。     

菲律宾蛤仔室内工厂化育苗试验

2005年5月在青岛红岛蛤原良种开发有限公司进行了室内自动控温条件下菲律宾蛤仔(Ruditapes philippinarum) 育苗试验,对试验结果进行了分析,并探讨了影响其性腺发育的因素和死亡高峰期的形成原因、对策。除此之外,还对菲律宾蛤仔浮游期和附着期的生长速率进行了比较,并对浮游期不同培育密度对生长、成活率的影响进行了初步研究。利用室内工厂化育苗技术,可以充分发挥高密度生产的优势,通过对苗种培育过程中水质、饵料和环境条件的全面控制,消除或减少敌害生物的影响,提高幼体的抗逆能力,从而杜绝抗生素的使用;在降低育苗生产环境污染的同时,向养殖户提供健康、优质的贝类苗种,是一种与环境相协调的、可持续的水产苗种培育模式。     

Growth,mortality and reproduction of the transplanted Manila clam (Ruditapes philippinarum Adams & Reeve 1850) in Jiaozhou Bay

Samples of Manila clam (Ruditapes philippinarum Adams & Reeve 1850) were collected from May 2004 to April 2005 monthly, and plankton net trawling of planktonic larvae and bottom sediment sampling surveys were further conducted from May to October 2006 in Jiaozhou Bay. Based on the data collected, growth, mortality and reproduction of the transplanted Manila clam and the environmental effects were examined. The results showed that the enhanced clams grew well and showed a growth trend similar to the local wild ones. The main growth periods lasted from April to September, with the water temperature being the main factor affecting the growth, which was the same as that of the wild clams. There were also two reproduction cycles for the farmed Manila clams each year in Jiaozhou Bay and the main breeding period was from May to June. The phenomenon of delayed metamorphosis was quite common through larval development. The farmed clams could spawn when they reached sexual maturity, but they could not perform effective recruitment as many planktonic larvae died during metamorphosis and settlement. A preliminary study indicated that sediment perturbation and marine environment pollution were the main factors causing the death of larvae in the development process.     

Heritability of larval and juvenile growth for two stocks of Manila clam Ruditapes philippinarum

The heritability of larval and juvenile growth in natural and cultured populations of the Manila clam Ruditapes philippinarum was estimated using an unbalanced nested design and an artificial fertilization technique. A total of 33 full‐sib families and 10 half‐sib families were obtained from the natural population in Shihe (Dalian, Liaoning Province in the north‐eastern part of China), whereas 11 half‐sib families and 33 full‐sib families were generated from the cultured population in Putian (Fujian Province in the south‐eastern part of China). The offspring from each family were reared under the same hatchery and nursery conditions. Results from these studies led to estimates indicating a significantly greater influence due to the dam component compared with the sire component for both natural and cultured populations, which was mainly due to maternal effect. We found that the heritability estimates obtained from the intra‐group correlation of sire half‐sib were precise and unbiased. The narrow‐sense heritabilities of shell length for the Manila clam in the natural population (NP) at larval (at the age of 9 days) and juvenile (at the age of 30 days) stages were 0.22 ± 0.11 and 0.39 ± 0.14, respectively, whereas those in the cultured population (CP) were 0.17 ± 0.09 and 0.87 ± 0.24 respectively. The heritabilities of both NP and CP at 3 days were not significantly different from zero, and were ?0.03 for NP and ?0.14 for CP. These results suggest that selection should be highly effective in Manila clam, and that selecting either a natural or a cultured population for producing faster growing larvae and juveniles should be successful. Selective breeding could thus be used to develop high‐quality seed that would facilitate the development of a shorter culture cycle and higher yields.     

Importance of shingle beaches as habitat for Manila clam Ruditapes philippinarum

Fisheries Science - We carried out surveys to clarify how the density (no. of individuals/m2) and condition factor (CF) of Manila clam Ruditapes philippinarum differ between estuarine tidal flats...     

Evaluation of macroalgal detritus as food source for juvenile Manila clam,Ruditapes philippinarum: Effects on growth,amino acid content and fatty acid composition

Sufficient high‐quality microalgae are required for indoor nursery of juvenile Ruditapes philippinarum. However, culturing numerous microalgae to support clam feeding is a heavy burden on many hatcheries. The effects of detritus from the macroalgae Ulva pertusa, Chondrus ocellatus and Undaria pinnatifida on the growth, amino acid content and fatty acid profile of R. philippinarum were assessed as potential substitute diets. The green microalga Tetraselmis cordiformis served as comparative diet. Results revealed that the clams ingesting distinct diets presented no significant differences in growth of soft tissues, but the nutritional component of these clams differed dramatically. The clams fed with Undaria + Tetraselmis had the highest content of essential amino acids and proteins. In addition, the clams fed with single macroalgal diets and mixed macroalgal detritus and Tetraselmis showed significantly higher or statistically equal levels in n‐3/n‐6 ratio and docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) ratio with respect to Tetraselmis diets. The relative percentages of EPA and DHA in clams fed with Undaria were 28% and 63% higher than those fed with Tetraselmis, and the arachidonic acid abundances in clams ingesting Undaria + Tetraselmis and Tetraselmis were significantly higher than those in clams ingesting other diets. Together, the diets containing single Undaria or mixed Undaria + Tetraselmis produced Manila clams with nutritional advantages in terms of essential amino acids and polyunsaturated fatty acids. Thus, the detritus of macroalgae, especially Undaria, is an appropriate substitute diet, at least partially, for culture of nutrition‐improved R. philippinarum.     

Larval recruitment of the manila clam Ruditapes philippinarum in Ariake Sound, southern Japan

ABSTRACT: The mechanisms by which catch yields of the manila clam Ruditapes philippinarum have decreased drastically in Kumamoto Prefecture, southern Japan, and the larval recruitment by which benthic populations of the clam are maintained were studied. Samples at different growth stages (planktonic larvae, new settlers, and small to large bivalves of the species) were collected from February 1997 to December 1998 on two tidal flats (Kawaguchi and Nameishi, 20 km distance from each other) along the eastern coast of Ariake Sound. Densities of planktonic larvae, new settlers and small bivalves were generally higher at Kawaguchi than Nameishi. The higher density of large bivalves at Kawaguchi depends on a high larval density. Larval retention mechanisms coupled with water movement at Kawaguchi, such as tidal residual currents, may be related intimately with the higher larval density at Kawaguchi. Predation by shore birds at and after recruitment may be related to the lower density of large bivalves recorded at Kawaguchi in 1998, despite larval densities being higher there.     

菲律宾蛤仔2个壳色品系群体杂交的研究

于2007年10月,以F1代海洋红（R）和斑马蛤（Z）为材料,开展了2个壳色菲律宾蛤仔（Ruditapes philippinarum）品系的群体杂交。试验由RR（R♀×R♂）、ZZ（Z♀×Z♂）、RZ（R♀×Z♂）和ZR（Z♀×R♂）组成。结果表明,2个壳色品系亲贝壳长、重量和产卵量差异显著（P〈0．05）。各试验组卵径、受精率和D形幼虫大小元显著差异（P〉0．05）,但杂交组孵化率显著高于相应对照组（P〈0．05）。浮游期间幼虫未表现出明显的生长优势,但表现出一定的存活优势。RZ和ZR的生长优势平均值分别为（1．63±0．81）％和（2．58±0．67）％;生长速度分别为（8．64±0．32）和（8．67±0．31）μm·d^-1,显著高于相应对照组（P〈0．05）;存活优势分别为（10．30±1．92）％和（16．30±1．04）％。室内培育期间稚贝表现出明显的生长、存活优势。RZ、ZR的生长优势平均值分别为（11．25±2．98）％和（20．31±2．10）％;生长速度分别为（9．88±1．45）和（10．79±1．32）μm·d^-1,显著高于相应对照组（P〈0．05）,存活优势分别为（40．85±9．90）％和（57．08±11．98）％。     

胶州湾菲律宾蛤仔生态容量评估及其碳汇功能

胶州湾是我国重要的菲律宾蛤仔(Ruditapes philippinarum)养殖基地,为探究湾内菲律宾蛤仔的生态容量及其碳汇功能,本研究采用Ecopath模型法评估了胶州湾菲律宾蛤仔的生态容量,并利用Ecosim模块动态分析了菲律宾蛤仔生物量扩大对胶州湾生态系统结构与功能特征的潜在影响,同时估算了胶州湾菲律宾蛤仔个体及种群水平的碳收支情况。结果显示,胶州湾菲律宾蛤仔的生态容量为239.9 t/km2,虽然整体水平尚未达到生态容量,但局部养殖区域已远超出了菲律宾蛤仔的生态容量;当胶州湾菲律宾蛤仔生物量从当前增加至生态容量时,生态系统总流量、容量、优势度和循环指数分别提高了16.0%、3.9%、47.1%和103.0%,而熵值降低了10.4%,表明此时生态系统具有更高的成熟度与稳定性,但菲律宾蛤仔生物量扩大至生态容量10倍时会对生态系统产生不利影响甚至崩溃;菲律宾蛤仔个体在1个养殖周期内约摄取3 310.1 mg C,其中约46.2%的碳沉降至海底,约13.2%的碳通过收获移出,如按菲律宾蛤仔生物量达到生态容量时计算,胶州湾每年将有1.5万t碳以生物沉积形式沉降至海底,有0.6万t碳以收获形式移出。研究结果为指导菲律宾蛤仔增养殖产业的健康可持续发展、阐明菲律宾蛤仔的碳汇功能提供了理论依据与数据支撑     

Expression and localization of MCsialec, a sialic acid-specific lectin in the marine bivalve Manila clam, Ruditapes philppinarum

A novel sialic acid-specific lectin (MCsialec) was detected from an expressed sequenced tag (EST) sequence from Manila clam haemocytes infected with Perkinsus olseni. The cDNA of the lectin was cloned using gene-specific primers based on a previously determined EST and characterized. The full-length cDNA of MCsialec is 603 bp in length and encodes a polypeptide of 200 amino acids with a calculated molecular mass of 21.928 kDa. Sequence alignment and protein motif analyses showed that MCsialec shares identity with sialic acid-specific invertebrate lectins from Cepaea hortensis, Helix pomatia and Haliotis discus discus. The lectin was expressed in Escherichia coli M15 cells and purified using a Ni-NTA His-binding resin matrix for antibody production. The presence of the lectin in various tissues of Perkinsus-infected and uninfected Manila clams was analysed by both PCR and immunohistochemical localization assays. MCsialec was detected in each tissue of the clams; however, upon infection, the level of expression of the lectin increased in each tissue. Vibrio tapetis infection also induced high-level expression of MCsialec in the haemocytes. These data suggest that MCsialec plays a crucial role in the immune system of the Manila clam during pathogenic infection.     

SEM observations on larval shell morphology of Manila clam Ruditapes philippinarum and their utility

Manila clam Ruditapes philippinarum is common and abundant on Japanese tidal flats, forming a commercially important clam fishery. However, annual catches of Manila clam have decreased drastically since 1975?C1985. To study larval recruitment processes of Manila clam, we carried out scanning electron microscopy (SEM) observations on larval and juvenile shells of clams reared at 20 and 24?°C. There was no significant difference in final shell length of trochophores between 20 and 24?°C. However, the larval duration was much longer and the shell length of settled size of pediveligers was much larger for clams reared at 20?°C than those reared at 24?°C. These findings suggest that larval duration and growth, as well as settlement size, may vary markedly depending on temperature (and probably on season). The larval shell morphology of Manila clam can provide essential information about larval recruitment processes.