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:     

菲律宾蛤仔浅海规模化苗种中间培育调查

为改进菲律宾蛤仔苗种中间培育技术,对福建省晋江市围头湾浅海中培的菲律宾蛤仔稚贝生长和海区环境进行了调查分析.结果 显示,从2019年1月到4月,海区水温逐渐上升,盐度逐渐下降,但均处于菲律宾蛤仔稚贝适宜范围;浮游植物以硅藻为主,1月份密度为5 100个/L,4月份密度为8 300个/L;菲律宾蛤仔稚贝壳长由(2.33±...     

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。     

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.     

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...     

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.     

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.     

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.     

Virus-like particles associated with brown muscle disease in Manila clam, Ruditapes philippinarum, in Arcachon Bay (France)

Recently, Manila clam, Ruditapes philippinarum , populations have suffered mortalities in Arcachon Bay (SW France). Mortality was associated with extensive lesions of the posterior adductor muscle, which become progressively brown and calcified. Ultrastructural observations by transmission electron microscopy revealed tissue degradation with necrotized muscle fibres and granulocytomas. Unenveloped virus-like particles (VLPs) were detected in muscle, granulocytic, epithelial and rectal cells. VLPs were abundant in the extracellular space, in the cytoplasm (free or enclosed in vesicles) and in the nucleoplasm of granulocytes. Nuclei and mitochondria of granulocytes displayed changes which suggested reactive oxygen species production and apoptosis induction. VLPs exhibited an icosahedral structure with a diameter of 25 to 35 nm. These observations suggest that the VLPs could belong to the family Picornaviridae or the Parvoviridae.     

Molecular detection of protists associated with the Manila clam Ruditapes philippinarum inhabiting the Wajiro tidal flat in Hakata Bay,Fukuoka Prefecture

Fisheries Science - Tidal flats are ecologically important as they support a large community of animals (e.g., crabs, mollusks, and polychaetes) and restore water quality. However, information...     

The effect of temperature on the energy budget of the Manila clam, <Emphasis Type="Italic">Ruditapes philippinarum</Emphasis>

In this study, the energy budget of the Manila clam, Ruditapes philippinarum, was evaluated after one-week acclimation periods at 5, 10, 15, 20, and 25°C. Small clams (151 ± 12 mg DW) and large clams (353 ± 16 mg DW) were fed with the microalgae, Isochrysis galbana. Filtration rate, ingestion rate, assimilation efficiency, oxygen-consumption rate, and ammonia excretion rate were measured. Both filtration rate and ingestion rate of small and large clams were found to be related to temperature. The highest Q ₁₀ values were measured in the range 15–20°C for both small and large clams. Assimilation efficiency of both small and large clams was not significantly influenced by temperature, although the maximum mean values were detected at 20°C. Oxygen consumption rate and ammonia excretion rate of small and large clams were found to be related directly to temperature over the entire range, with a maximum being detected at 25°C. The highest Q ₁₀ value was estimated in the range 10–15°C with regard to oxygen consumption rate, and in the range of 15–20°C with regard to ammonia excretion rate. Scope for growth (SFG) was positive at all temperatures, achieving a maximum value at 20°C in both small and large clams, primarily as a consequence of the enhanced ingestion rate which offset the concomitant elevation in the metabolic rate. In this study we have estimated the thermal optimum for this species at 20°C.