Size-differential feeding in Pinna nobilis L. (Mollusca: Bivalvia): Exploitation of detritus,phytoplankton and zooplankton

The endangered fan shell Pinna nobilis is a large bivalve mollusc (<120 cm shell length) endemic to the Mediterranean that lives one-third buried in soft substrata, generally in shallow coastal waters. We hypothesised that P. nobilis of different sizes would ingest different food sources, because small fan shells will inhale material from closer to the substratum than do large fan shells. We studied stomach contents and faeces of 18 fan shells, 6 small (mean 23.0 cm length), 6 medium-sized (mean 41.5 cm length) and 6 large (mean 62.7 cm length) living in a small area of a low-energy coastal detritic bottom characterised by mud, sand and macroalgae at Mali Ston Bay, Croatia. We found that all P. nobilis ingested copious quantities of undetermined detritus (probably at least 95% of ingested material), phytoplankton, micro and mesozooplankton and pollen grains. Large P. nobilis stomach contents showed a preponderance of water column calanoid copepods, while small fan shells had higher numbers of bivalve larvae. All fan shells took in high numbers of harpacticoid copepods that are benthonic, feeding on microbial communities of detritus and benthic vegetation. There was also a significant selection of phytoplankton species, some apparently occurring between inhalation and ingestion. The stomach contents of small P. nobilis had a higher organic matter content than either medium-sized or large fan shells; this indicated that small fan shells ingested detritus of higher organic content than did larger P. nobilis. As the faeces of all P. nobilis had similar organic matter content, this also indicates higher assimilation efficiencies in small fan shells. The demonstration of differential dietary selectivity by different sized animals has implications for future trophic studies of this endangered species. This study also provides the first demonstration of predation on zooplankton by P. nobilis.     

The effect of hydrodynamics on shell orientation and population density of Pinna nobilis in the Gulf of Oristano (Sardinia,Italy)

Pinna nobilis is the largest endemic bivalve of the Mediterranean Sea, declared protected since 1992. Although hydrodynamic stress induced by waves is known to influence density, size and orientation of P. nobilis, the effect of other hydrological features is unknown. This paper considers a P. nobilis population living within a Posidonia oceanica meadow in the Gulf of Oristano (Sardinia, Italy). We hypothesize that spatial differences in density and orientation of P. nobilis may be related to significant wave height (H_S), wave direction (D_W), bottom current direction (D_BC) and bottom current speed (S_BC). A population of P. nobilis was investigated at different sites and its distribution was correlated to hydrodynamics by means of a numerical modeling approach. The spatial distribution was patchy, with a density of 0.06–6.7 ind. 100 m^− 2. A non-uniform distribution of shell orientations (O_S) was demonstrated in 4 sites out of 6. D_BC and S_BC were the main factors affecting O_S, while waves had little influence. A S_BC of 0.07 m s^− 1 appears to be the threshold for inducing specimen directionality with shells aligned to the current and the ventral side exposed to the flow. This suggests that feeding strategy is a key factor in determining O_S, in addition to drag minimization. We also highlighted the role of adjacent lagoons in supporting high densities as a result of high food availability. These findings demonstrate the usefulness of modeling techniques in explaining the spatial distribution pattern of P. nobilis and in contributing to our knowledge of its ecological traits.     

Epibiotic assemblages on the pen shell Pinna rudis (Bivalvia,Pinnidae) at Matiota Beach,São Vicente Island,Cabo Verde

The rough pen shell Pinna rudis Linnaeus, 1758 (family Pinnidae), a mollusc with an Atlantic–Mediterranean distribution, is able to live in coarse sandy substrates. Considering its shell structure and ecological characteristics, P. rudis can enhance biodiversity by providing a substrate for settlement on its shell. For this reason, we compared the diversity of benthic taxa around P. rudis shells with the species diversity on P. rudis shells, at Matiota Beach, São Vicente Island, Cabo Verde. We sampled an area of 900 m2 and recorded data in situ to estimate the population size of P. rudis and the epibiotic and benthic community diversity. The average density of P. rudis estimated in the sampled area was 6.6 ind. 100 m–2 and the highest density was found at between 2 and 3 m depth, mostly in biogenic and sandy substrates. The epibiotic species diversity on P. rudis shells was significantly higher than the species diversity in the microhabitat around the shells. The P. rudis shell seems to play an important role in increasing the biodiversity of the ecosystem, with some species found only as epibionts on P. rudis.     

华贵栉孔扇贝(Chlamys nobilis)壳色与闭壳肌颜色遗传规律的研究

华贵栉孔扇贝壳色和闭壳肌颜色具有多态性,其中贝壳的桔黄色表型和闭壳肌的黄色表型具有重要的经济价值,是选择育种中的重要目标性状,对这些性状遗传规律的研究可为选择育种提供理论依据。采用自交、正反杂交和卡方检验方法对华贵栉孔扇贝的桔黄色与枣褐色等2个壳色和黄色与白色等2个闭壳肌颜色的遗传规律进行了研究。结果表明,华贵栉孔扇贝贝壳颜色和闭壳肌颜色均属质量性状,受基因控制,可以遗传,不受环境影响;贝壳桔黄色表型对枣褐色表型为显性;闭壳肌白色表型对黄色表型为显性;壳色和闭壳肌颜色为两个互不连锁的独立性状,在后代遗传过程中可以自由组合,独立遗传,不受母性影响;枣褐色贝壳或黄色闭壳肌个体均为隐性纯合体,其后代性状均与亲代相同;由于不能确定桔黄色贝壳或白色闭壳肌个体属于显性纯合还是杂合,显性纯合家系的获得必须通过建立家系并繁育2代才能实现。     

Mass mortality of the fan mussel,Pinna nobilis in Turkey (eastern Mediterranean)

This study reported the mass mortality events (MMEs) of Pinna nobilis based on diving surveys in Turkey. Data were collected across 12 sites in the Aegean Sea, and one site in the Sea of Marmara, within the period of June-September 2019. The results showed that a low mortality rate of 10% was found in the Sea of Marmara, and a MME was not detected for this area. In contrast, 97% mortality was recorded for the P. nobilis population distributed in the Turkish Aegean Sea. This discrepancy might be related to the seawater temperature and salinity values of these two seas. The waters of the Sea of Marmara were colder and less salty than the Aegean Sea. The findings highlighted the importance of protecting the healthy population of critically endangered fan mussels in the Sea of Marmara. It was recommended that sound management plans comprising of monitoring, enforcement and public awareness activities could be implemented in order to achieve this.     

几何形态学对8种扇贝的形态分类的应用

几何形态学(morphometrics)是基于笛卡尔地标点的统计分析方法,主要运用广义普鲁克分析(GPA)、薄板样条分析(TPS)、主成分分析(PCA)、典型变量分析(CVA)等方法,定量的对形态变化进行识别,结果更为客观。本研究运用几何形态学方法对8种常见扇贝(栉孔扇贝Azumapecten farreri、虾夷盘扇贝Mizuhopecten yessoensis、海湾扇贝Argopecten irradians、平濑掌扇贝Volachlamys hirasei、北海道扇贝Swiftopecten swiftii、荣套扇贝Gloripallium pallium、华贵类栉孔扇贝Mimachlamys nobilis、美丽环扇贝Annachlamys striatula)间形态关系进行研究,运用界标点和半界标点对扇贝的壳盘和壳耳进行数字化标点,利用PCA、CVA、TPS方法,获得8种扇贝的形态差异并进一步分析,建立系统发育树。PCA和CVA分析结果表明可以通过几何形态测量学分析方法将8种扇贝基于形态差异进行有效区分。此外,结合TPS的分析结果,发现壳耳和壳盘在扇贝中具有种间规律性差异。通过其形态分异进行表型聚类,从结果可知:美丽环扇贝、虾夷盘扇贝和海湾扇贝距离较近,壳型有共同的特征:扇贝壳盘较椭圆,壳耳相对较小;荣套扇贝和华贵类栉孔扇贝距离较近,壳型有共同的特征:扇贝壳盘更扁平,前耳相对较大;北海道扇贝、平濑掌扇贝和栉孔扇贝与其他种类没有交集。在聚类过程中,华贵类栉孔扇贝和荣套扇贝有交集,10个标本混淆,其他标本均成功聚类,正确率为95.5%。     

Growth rates of the infaunal bivalve Soletellina alba (Lamarck, 1818) (Bivalvia: Psammobiidae) in an intermittent estuary of southern Australia

Caging and a mark–recapture design were used to estimate the growth rate of the brittle, infaunal bivalve Soletellina alba in the Hopkins River estuary. The growth of both caged and uncaged individuals was monitored at three sites near the mouth of the estuary over 180 days. Growth rates did not differ for caged and uncaged bivalves, or for bivalves subject to different amounts of handling, or between sites. Growth did differ between consecutive time intervals, which was attributable to negligible growth occurring during the colder months of autumn/winter. Comparisons of the condition (as indicated by total mass for length³) of S. alba were inconsistent between sites for caged and uncaged bivalves and for those subject to different amounts of handling. Soletellina alba is a rapidly growing bivalve with mean growth rates for the three time intervals being 0.04±0.002 mm day⁻¹ in summer, 0.02±0.001 mm day⁻¹ in autumn and 0.03±0.001 mm day⁻¹ from summer to winter. Using existing literature, it was shown that a significant relationship exists between maximum shell length and onset of sexual maturity in bivalve molluscs. This relationship predicts that S. alba should reach the onset of sexual maturity at 15.8 mm length. Therefore, it appears that it may be possible for juvenile S. alba (<1 mm) to grow, reach sexual maturity and reproduce in between annual mass-mortality events caused by winter flooding.     

黑花鳙(Aristichthys nobilis)和白花鳙肌肉营养成分分析及营养价值评定

采用常规营养成分分析方法,研究了新选育品种黑花鳙和白花鳙F2代的含肉率、肌肉生化成分和能值。结果表明,二者的含肉率分别为77.47%和77.53%;鲜样中肌肉生化成分分别为:水分80.56%和79.38%,蛋白质17.01%和17.67%,脂肪0.87%和1.20%,灰分1.25%和1.35%,比能值4.43kJ/g和4.72kJ/g;干样中黑花鳙17种氨基酸总含量(81.32g/100g),9种人体必需氨基酸含量(40.05g/100g),四种呈味氨基酸含量(29.13g/100g)均小于白花鳙(86.63,42.04,31.57g/100g),但其必需氨基酸/氨基酸总含量(49.25%)以及必需氨基酸/非必需氨基酸(0.97)均大于白花鳙(48.53%,0.94)[以上差异均不显著(P0.05)];二者的限制性氨基酸为缬氨酸、亮氨酸和苏氨酸。黑花鳙必需氨基酸与总氮的克数比(2.62)以及必需氨基酸指数(77.98)均小于白花鳙(2.67,79.6),但都大于湖北等产地的鳙鱼。两种新选育的鳙鱼开发利用前景看好。     

不同月龄青蛤形态性状对活体质量的影响分析

随机选取5月龄、10月龄、15月龄的青蛤(Cyclina sinensis)混合家系各220枚作为研究对象,通过测定其壳长(SL)、壳高(SH)、壳宽(SW)和活体质量(W),并采用相关性、通径和决定系数的统计分析探讨青蛤形态性状对活体质量的影响效力。结果表明:各性状与活体质量间的相关性均达极显著水平(P0.01),其中5月龄、10月龄和15月龄相关系数最大的均为壳高;通径分析结果显示,对不同月龄的活体质量的直接影响最大的均是壳高、其次壳宽、最后壳长;5月龄和15月龄的壳高和壳宽共同决定系数最大,分别为0.269和0.262, 10月龄的壳高决定系数最大为0.338。利用逐步回归的方法分别建立5月龄、10月龄、15月龄青蛤活体质量的最优回归方程分别是:W5=–0.564+0.061SH+0.051SW,R2=0.933;W10=–2.585+0.040SL+0.149SH+0.101SW,R2=0.934;W15=–7.359+0.123SL+0.210SH+0.273SW,R2=0.957。本研究结果可为青蛤高产新品系阶段选优和良种选育提供基础数据。     

High-resolution isotopic records (δ 18O and δ 13C) and cathodoluminescence study of lucinid shells from methane seeps of the Eastern Mediterranean

We present high-resolution isotopic records and cathodoluminescence studies of recently dead and live bivalve specimens from cold seeps, in an attempt to reconstruct environmental conditions during organism growth, and thereby the possible variability of fluid-venting activity at the seafloor. Shells of the burrowing lucinid Myrtea aff. amorpha were collected at three localities near actively venting methane seeps in the Eastern Mediterranean deep sea, using the Nautile submersible during two French oceanographic cruises: from the Kazan mud volcano, in the vicinity of the Anaximander mounts (MEDINAUT cruise, 1998), and from the central pockmark province and the Amon mud volcano of the Nile deep-sea fan (NAUTINIL cruise, 2003). The oxygen and carbon isotope compositions of 18 shells from the various localities, and also from different sites at the same locality show a rather strong scatter (1.8 < δ ¹⁸O‰ < 3.4; −10.2 < δ ¹³C‰ < 2.2), and values lower than those expected for carbonate precipitated at equilibrium with present-day bottom waters. This means that warm methane-rich fluids were mixed with bottom seawater during precipitation of shell carbonates. We have tried to determine ontogenetic age of two shells by using cathodoluminescence as a sclerochronological proxy, because the direct counting of carbonate increments was not possible in these specimens. There is a relatively good correspondence between cathodoluminescence trends and oxygen isotope profiles that might support the link between manganese incorporation during growth and temperature. Eight specimens of lucinid shells were selected for high-resolution isotopic profiling. A few shells exhibit decreasing δ ¹⁸O and δ ¹³C values from the umbo to the actively growing ventral shell margin, which can be attributed to the commonly observed physiologically controlled deceleration of growth with increasing organism age, this metabolic effect corresponding to the increase of incorporation of respiratory CO₂. A few shells exhibit high-frequency δ ¹⁸O variations with an amplitude of about 1.5‰ that might be related to temperature variations controlled by fluid-venting activity. One shell from the pockmark province of the Nile deep-sea fan records a strong, sharp δ ¹³C decrease of about 9‰, and extending over a 5-mm interval in the shell that can be related to a major methane release event. Another shell from the Kazan mud volcano exhibits a progressive increase of δ ¹³C values from −10‰ to 0‰ with age, which might indicate decreasing methane flow throughout the organism’s life. This study has demonstrated that bivalve shells from deep-sea cold seeps represent good indicators of variability in seepage activity of methane-rich fluids, at various scales in both space and time. Although the precise chronology of the observed events was not established, because shell growth rate is not known in this case, this remains a priority for future studies in such environments.     

Shell form,growth, and production of Astarte borealis (Schumacher, 1817) (Astartidae,Bivalvia) in the southeastern Baltic Sea

The relationships between the linear dimensions and body weight and the ratio between the masses, growth, and production were studied for the bivalve Astarte borealis inhabiting the southeastern Baltic Sea. The maximal shell length was 21.09 mm, while the maximum age was 8+. The linear growth was described by the Bertalanffy equation L _τ = (1 - e ^{-0.0894(τ-(-0.7354))}). The annual production was 7.60 kJ/m² at a P _s/B coefficient of 0.41. It was found that the A. borealis inhabiting the southeastern Baltic Sea was characterized by a lower linear growth rate compared to the mollusks of other parts of the geographical range due to the low salinity of the Baltic Sea.     

马氏珠母贝黄壳色家系的生长、壳色分离及总抗氧化能力比较

以马氏珠母贝(Pinctada fucata martensii)黄壳色作为选育指标构建了黄壳家系,对其4个生长性状和黄壳色性状分离比进行了统计分析,并测定了黄壳家系中黄壳、褐壳色个体不同组织中的总抗氧化能力(TAC)。结果发现:黄壳色性状能遗传并发生分离,其分离不完全符合孟德尔遗传分离定律;褐壳色亲本不会产生黄壳色子代,推测褐壳色是纯合子;第一代黄壳家系5、7月龄贝仅壳宽值显著小于褐壳家系(P0.05),壳高、壳长、总质量差异不显著, 11月龄贝仅壳长和壳宽值显著小于褐壳家系, 14、20月龄贝的壳高、壳长、壳宽、总质量这4个生长性状均极显著小于褐壳家系(P0.01);在第一代6个黄壳家系内,黄壳、褐壳色个体的4个生长性状差异不显著;黄壳色贝在足、心、性腺中的TAC显著低于褐壳色贝(P0.05);在鳃、闭壳肌、消化腺组织中TAC高于褐壳色贝,但差异不显著。     

基于贝壳生长轮方法的平端深海偏顶蛤的生长和年龄结构研究

平端深海偏顶蛤(Gigantidasplatifrons)是广泛分布于西太平洋深海热液和冷泉生态系统中的优势种和共有种,也是深海化能生态系统中重要的生境营造种。以南海F冷泉平端深海偏顶蛤为研究对象,基于贝壳日生长轮方法,分析了平端深海偏顶蛤的年龄与生长速率,建立了其年龄与贝壳壳长关系的生长方程。同时,结合获得的生长方程,分析了南海F冷泉采样点(119.285 6°E,22.115 4°N)平端深海偏顶蛤种群的年龄结构。研究结果表明,采样获得的平端深海偏顶蛤种群的最大壳长为11.4 cm,最大寿命为13.5龄。研究区域的贝壳长度分布集中在4～7 cm,占比60%;年龄分布集中在2～4龄,占比49.7%。相关研究结果为进一步开展平端深海偏顶蛤的生长研究提供了基础数据,有助于深入了解冷泉区域的种群动态变化规律。     

3月龄脉红螺表型性状对体质量影响效应分析

随机抽取3月龄脉红螺稚螺103粒,开展其表型性状对体质量性状影响分析,以期为脉红螺人工选择育种提供较好的测度指标。实验测量了脉红螺壳长（X₁）、壳宽（X₂）、壳厚（X₃）、壳口长（X₄）、壳口宽（X₅）等5种表型性状和体质量性状（Y）,运用相关性分析、多元回归分析、通径分析及决定系数分析等方法分析了表型性状对体质量性状的影响。结果表明,脉红螺各性状间的相关性均达到极显著水平（P<0.01）,拟合的多元线性方程为Y=-18.484 4+0.348 35X₁+0.463 79X₂,经自助法检验,在95%置信区间条件下,该方程决定系数（R²）范围为0.863 5~0.939 4,拟合度较好;壳长和壳宽对体质量的决定系数之和大于0.85,是最适宜用来预测体质量性状的两个表型性状指标。本研究成功分析出对脉红螺体质量直接影响作用最强的表型性状,为脉红螺选择育种理想测度指标的挑选提供了依据。     

长牡蛎F3 代快速生长选育群体生长特性的研究

采用模型拟合方法研究了长牡蛎(Crassostrea gigas)F3代快速生长选育群体不同时期各生长性状的发育规律。结果表明,长牡蛎幼虫期壳高(SH)、壳长(SL)对日龄(t)的回归遵循Logistic模型,生长方程分别为SH=455.612/(1+9.500e-0.142t),R2=0.999;SL=462.476/(1+8.026e-0.108t),R2=0.996。幼虫期壳高与壳长成直线相关,回归方程为SL=0.76SH+18.82,R2=0.994。长牡蛎养成期各生长性状呈现明显的季节变化,壳高(SH)、壳长(SL)、壳宽(SW)和总质量(TW)对月龄(X)的多项式回归方程分别为SH=-0.0297X4+1.0365X3-12.0220X2+57.6500X-68.9260,R2=0.985;SL=-0.0173X4+0.5893X3-6.5702X2+30.2420X-34.4150,R2=0.986;SW=-0.0068X4+0.2620X3-3.2806X2+16.9170X-22.1410,R2=0.956;TW=-0.0219X4+0.8234X3-10.1680X2+50.7040X-85.4110,R2=0.972。壳高、壳长、壳宽与总质量均呈幂函数相关,回归方程分别为SH=23.645TW0.3213,R2=0.998;SL=12.337TW0.3776,R2=0.995;SW=6.611TW0.3589,R2=0.981。     

基于GLM模型Logistic回归的菲律宾蛤仔地理群体判别

菲律宾蛤仔(Ruditapesphilippinarum)是重要的海洋经济贝类和海水养殖品种,具有较强的表型可塑性特点,不同地理群体之间存在表型差异。本研究根据实测数据建立了胶州湾与天鹅湖菲律宾蛤仔壳长(SL)与壳高(SH)、壳宽(SW)和活体重(W)的回归方程,定量分析了两个地理群体的形态学差异。由于其近似圆形的形态使得所能测量的外部指标较少,限制了传统形态测量学在其地理群体判别中的应用。本研究提出了将传统形态测量学和广义线性模型(GLM)相结合的方法,建立了判别菲律宾蛤仔地理群体的逻辑斯蒂(Logistic)回归方程。结果表明:菲律宾蛤仔的天鹅湖群体比胶州湾群体具有更高的SH/SL和SW/SL比值,壳形椭圆较圆且隆起程度高,"凸"形明显;基于GLM模型的Logistic回归能够快速准确地判别菲律宾蛤仔的地理群体归属,判别正确率高达94.23%。本研究为双壳类物种地理群体判别提供了新的分析方法和技术手段。     

Cold seep communities in the deep eastern Mediterranean Sea: composition, symbiosis and spatial distribution on mud volcanoes

Two mud volcano fields were explored during the French–Dutch MEDINAUT cruise (1998) with the submersible NAUTILE, one south of Crete along the Mediteranean Ridge at about 2000 m depth (Olimpi mud field) and the other south of Turkey between 1700 and 2000 m depth (Anaximander mud field) where high methane concentrations were measured. Chemosynthetic communities were observed and sampled on six mud volcanoes and along a fault scarp. The communities were dominated by bivalves of particularly small size, belonging to families commonly found at seeps (Mytilidae, Vesicomyidae, Thyasiridae) and to Lucinidae mostly encountered in littoral sulfide-rich sediments and at the shallowest seeps. Siboglinid polychaetes including a large vestimentiferan Lamellibrachia sp. were also associated. At least four bivalve species and one siboglinid are associated with symbiotic chemoautotrophic bacteria, as evidenced by Transmission Electronic Microscopy and isotopic ratio measurements. Among the bivalves, a mytilid harbors both methanotrophic and sulfide-oxidizing bacteria. Video spatial analysis of the community distribution on three volcanoes shows that dense bivalve shell accumulations (mainly lucinids) spread over large areas, from 10% to 38% of the explored areas (2500–15000 m²) on the different volcanoes. Lamellibrachia sp. had different spatial distribution and variable density in the two mud volcano fields, apparently related with higher methane fluxes in the Anaximander volcanoes and maybe with the instability due to brines in the Olimpi area. The abundance and richness of the observed chemosynthetic fauna and the size of some of the species contrast with the poverty of the deep eastern Mediterranean. The presence of a specialized fauna, with some mollusk genera and species shared with other reduced environments of the Mediterranean, but not dominated by the large bivalves usually found at seeps, is discussed.     

不同养殖海域栉孔扇贝(Chlamys farreri)混合家系的通径分析

为了深入认识栉孔扇贝(Chlamys farreri)壳尺寸性状和体重之间的关系,达到通过直观可见形状判断非直观性状,在栉孔扇贝苗种培育中指导种贝挑选工作的目的,本实验将600余只扇贝分别于三个不同纬度养殖环境(山东青岛、山东荣成和辽宁大连)下养殖一年后测量其性状数据,包括壳长、壳高、壳宽、体重,进行壳尺寸性状对体重性状的通径分析。偏回归系数统计表明,除大连海域壳长对体重的偏回归系数为0.266,差异不显著(P0.05)外,其它参数对体重均极显著(P0.01),表明大多数自变量和因变量之间都有极显著的共线性关系。对各个海域建立以壳尺寸为自变量,体重为因变量的回归方程,得出通径系数、各性状间的相关性指数以及各参数对体重的决定系数,计算出了不同养殖地点的栉孔扇贝壳尺寸性状和体重之间关系的回归方程。通径分析显示,对青岛海域栉孔扇贝体重直接作用最大的是壳高,对荣成海域栉孔扇贝体重直接作用最大的是壳长,而对大连海域栉孔扇贝体重直接作用最大的是壳宽。因此,以体重为目标挑选青岛海域的种贝时,应以壳高为优先选择指标;挑选荣成海域的种贝时,优先选择壳长;挑选大连海域的种贝时,优先选择壳宽。不同养殖海域栉孔扇贝的通径分析为栉孔扇贝亲贝的挑选提供了理论支持。     

马氏珠母贝两个与生长性状相关QTL 的验证

利用2个马氏珠母贝群体对遗传连锁图谱已经定位的,与马氏珠母贝生长性状相关的数量性状位点(Quantitative trait locus,QTL)中的两个进行验证。结果显示:m59标记在2个群体中与壳高、壳长、壳宽和总重具有显著的相关性(P0.05),其GT基因型的个体壳高、壳长、壳宽和总重均显著高于GG基因型的个体;154165标记在湛江群体中与壳高具有显著相关性(P0.05),而在深圳群体中与壳宽具有显著相关性(P0.05);表明QTL标记m59在2个群体中是共享QTL,而154165标记在群体中是特异QTL。基于这两个QTL在这2个群体中分别构建二倍型,发现在湛江群体中二倍型C_1(AAGT)和深圳群体中D_1(AGGT)型和D_2(AAGT)型对马氏珠母贝生长最为有利,可作为优先的基因型组合。     

青蛤(Cyclina sinensis)贝壳形态性状对软体部重的影响分析

随机抽取中国及日本海域的1龄青蛤(Cyclina shiensis)245个,分别测量其壳高、壳长、壳宽、韧带长、壳重及软体部重等形态学和生产性状,采用相关分析、通径分析、决定系数分析和多元回归分析方法,讨论了贝壳各形态性状对软体部重的影响.结果表明,青蛤的壳高对软体部重相关系数r1y和直接影响通径系数Pi分别达到了0.953和0.938,统计检验均达到了极显著水平(P<0.01).此外,壳高对软体部重的决定系数R12为0.9080,多元回归分析亦显示出青蛤的壳高与软体部重具有显著的相关性(P<0.01).实验结论认为,壳高对青蛤的生产性状影响最大,可以作为青蛤种质选育的重要甄别性状.