牙鲆家系亲权鉴定的微卫星DNA标记分析

为准确进行不同家系的亲权鉴定,筛选具有高亲本排除概率的微卫星DNA标记,从牙鲆选育基础群体中挑选性腺发育良好的雌雄亲本各10尾建立全同胞家系10个,从独立饲养的每个家系中随机选取30尾个体组成系谱结构已知的家系群体,从混合培育的子代群体中随机选取200尾个体组成系谱结构未知的混合群体。48个微卫星DNA标记选自牙鲆第二代遗传连锁图谱,且均匀分布于24个连锁群上,每个连锁群2个标记。家系群体的遗传分析结果发现,10个拥有丰富遗传多态性的微卫星DNA标记表现出高的亲本排除概率,其Excl1和Excl2的范围分别为0.655~0.719和0.792~0.837。随鉴定所用微卫星DNA标记数目的增加,累计排除概率逐步升高。当使用8个微卫星DNA标记鉴定时,累计排除概率达到100%。利用这些标记开展混合群体的亲权鉴定,显示共有13个雌雄个体参与繁殖过程,不同亲本配组产生的后代数量存在差异,亲本与后代群体之间的各项遗传学统计指标不存在明显差异。研究表明,筛选出具有高亲本排除概率的微卫星DNA标记能够有效进行牙鲆家系的亲权鉴定,可以作为今后开展家系选育与DNA分子标记联合育种的候选标记。     

光照周期对褐牙鲆幼鱼生长、能量分配及生化指标的影响

在循环水实验系统中,设置1 L∶23 D、9 L∶15 D、12 L∶12 D、15 L∶9 D、24 L∶0 D(光L∶暗D)共5个光照周期处理组,研究其对褐牙鲆幼鱼生长及部分生化指标的影响。实验结束时褐牙鲆幼鱼的体质量为41.10~43.98 g,不同处理组间无显著差异,体质量未表现出与日光照周期长短的相关性。日生长系数只在21~30 d阶段内出现显著差异,整个实验期间的平均日生长系数为1.86~2.02,不同处理组间不存在显著差异,日生长系数随日光照周期的延长略呈下降趋势。不同阶段的摄食率在31~40 d阶段出现显著差异,12 L∶12 D处理组摄食率显著高于9 L∶15 D处理组。在整个实验期间,1 L∶23 D的褐牙鲆幼鱼摄食率为1.64,显著低于12 L∶12 D的褐牙鲆幼鱼的摄食率(1.79)。整个实验期间,1 L∶23 D的褐牙鲆幼鱼平均饲料转化效率为113.49,显著高于12 L∶12 D、15 L∶9 D、24 L∶0 D的褐牙鲆幼鱼,并略高于9 L∶15 D的褐牙鲆幼鱼,饲料转化效率随光照时间的延长呈下降趋势。实验期间摄食能的分配比例仅在排泄能上出现显著差异,15 L∶9 D最高,12 L∶12 D最低,其他各项能量分配均无显著差异。不同光照周期对耗氧率影响显著,15 L∶9 D最高,为0.252 mg/(g·h),24 L∶0 D最低,为0.173 mg/(g·h)。耗氧率随着光照时间的延长呈先上升后下降的趋势。血浆生长激素和类胰岛素生长因子I含量在不同处理组间也不存在显著差异,随光照时间延长也未表现出明显变动趋势。血浆褪黑素含量随光照时间的增加呈先下降后上升的趋势,12 L∶12 D处理组MT含量最低,但与其他处理组差异不显著。实验结束时肌肉RNA/DNA比值随光照周期延长呈先上升后下降变动趋势,其中15 L∶9 D和24 L∶0 D处理组的肌肉RNA/DNA比值显著高于1 L∶23 D处理。肝脏RNA/DNA比值以12 L∶12 D最高,15 L∶9 D最低。实验结果表明光照周期对褐牙鲆幼鱼摄食量和饲料转化效率产生显著影响,但摄食量减少的处理组由于耗氧率降低因而饲料转化效率得到提高,因此光照周期对生长没有显著影响。光照周期明显影响血浆褪黑素、肌肉和肝脏RNA/DNA比值,但生化指标的差异与生长无明显相关性。     

Effect of feeding ratio on growth and body composition of juvenile olive flounder Paralichthys olivaceus fed extruded pellets during the summer season

The effect of feeding ratio on growth and body composition of juvenile olive flounder fed extruded pellets was determined during the summer season. Thirty juvenile olive flounder (initial body weight of 17 g) per tank were distributed into 21, 180-l flow-through tanks. Seven treatments that included triplicate groups of feeding ratio in 5% decrement were prepared for this study: 100% (satiation), 95%, 90%, 85%, 80%, 75% and 70% of satiation. Fish in the control group were hand-fed to apparent satiation twice a day. Then feed allowance in the rest of the six groups was determined based on average feed consumption in the control group. The feeding trial lasted for 7 weeks. Survival was over 97% and was not significantly (P > 0.05) affected by the feeding ratios. Weight gain and SGR of fish fed to 100% of satiation were not significantly different from those fed to 95% of satiation but significantly (P < 0.05) higher than those of fish fed to 90%, 85%, 80%, 75% and 70% of satiation. Weight gain, SGR and feed consumption of flounder linearly (P < 0.001) decreased with a decrease in feeding ratio. However, feed efficiency ratio, protein efficiency ratio and protein retention in fish body were not significantly (P > 0.05) affected by the feeding ratio. The crude protein levels of the whole body without liver or liver were significantly affected by the feeding ratio. Hepatosomatic index and condition factor of fish were not significantly (P > 0.05) affected by the feeding ratio. It can be concluded that optimum feeding ratio for growth of juvenile olive flounder could be lowered to 95% of satiation without growth suppression.     

Reproductive behaviour and early development in yellowtail kingfish (Seriola lalandi Valenciennes 1833)

The spawning behaviour of wild caught brood stock as well as early egg and larval development were studied in yellowtail kingfish (Seriola lalandi). Spawning occurred naturally in the austral spring/summer (November-February) when the seawater temperature was above 17 °C. Courtship behaviour involved one male and female, and consisted of a high-speed pursuit punctuated by stalling, nipping and touching. This lasted for approximately 0.5-1.5 h until, immediately prior to spawning, the male would nip at the female gonoduct, presumably to induce spawning. At this stage, in 50% of spawns, a second male would become involved. The release of gametes involved frenzied circling behaviour near the bottom of the tank and lasted approximately 22 s. Spawning occurred in the early daylight hours at the start of the spawning season, but shifted to around dusk in the latter part. Spawned eggs were positively buoyant, had a high fertilisation rate (> 99%), ranged 1.33-1.50 mm in diameter with a single oil droplet 0.30-0.33 mm diameter, and developed in a similar manner to that described in congenerics. Egg viability within the floating fraction was visually determined to be 74% ± 17% over the entire reproductive season. Indistinct cell margins and asymmetrical cleavage were the most common blastomere deformities observed. Egg and oil droplet volume were found to decrease by 15-20% over the spawning season, though no relationship was found between visually assessed egg viability and date. Egg incubation trials between 16 and 24 °C indicated that temperature accelerated the time to hatch by a Q₁₀ of 5.0. While larvae were found to hatch at a smaller length with a larger yolk sac and oil droplet at warmer incubation temperatures, there was little difference in the maximum larval length reached at the onset of first feeding among the rearing temperatures used. It is proposed that the reason for this was that higher incubation temperatures accelerated the hatching process faster than the rate of tissue deposition. The findings from this study are discussed in terms of the biological significance and implications for the larviculture of this species.     

牙鲆皮肤黏液免疫球蛋白的纯化及部分特性分析

采用饱和硫酸铵分步盐析结合Sephacryl S-300凝胶过滤层析及DEAE Sepharose离子层析法,对牙鲆皮肤黏液中的免疫球蛋白(Ig)进行了分离纯化,并通过SDS-PAGE及Western-blotting技术对纯化蛋白的部分特性进行了分析。结果表明,30%、50%饱和硫酸铵分步盐析可以去除牙鲆黏液中除Ig外的很多杂蛋白,得到粗提黏液Ig;再经Sephacryl S-300纯化,Ig纯度较高,其中含有72和26 ku的条带;DEAE Sepharose层析法可进一步纯化Sephacryl S-300柱层析的产物,所提取黏液Ig经SDS-PAGE检测,只含有72和26 ku两个条带,初步认为是牙鲆黏液Ig的重链和轻链。Western-blotting结果显示,抗牙鲆血清Ig单克隆抗体可与黏液Ig重链72 ku条带发生发应。     

Study on the distribution and expression of a DNA vaccine against lymphocystis disease virus in Japanese flounder (Paralichthys olivaceus)

The distribution and expression of lymphocystis disease virus (LCDV) vaccine, on the basis of DNA vaccine (pEGFP-N2-LCDV0.6 kb) construction, were analyzed in tissues of the Japanese flounder by PCR, RT-PCR and fluorescent microscopy. Results from PCR studies indicated that the vaccine-containing plasmids were distributed in injected muscle, muscle located opposite the injection site, hind intestine, gill, spleen, head kidney, liver and gonad 7 days after vaccination. However, these vaccine-containing plasmids disappeared by 90 days following vaccination. Fluorescent microscopy observations revealed that green fluorescence appeared in muscle, muscle located at the opposite side of the injection site, hind intestine, gill, spleen, head kidney and liver of fish 36 h after vaccination, and that green fluorescence did not appear in control tissue. The green fluorescence became weaker at 60 days post-vaccination, however, it remained detectable in the spleen 90 days post-vaccination. Results from RT-PCR studies indicated that the Mcp gene is expressed in all tissues of vaccinated fish 7-20 days after vaccination. These results demonstrate that the DNA vaccine is distributed and expressed in different tissues of vaccinated fish, and therefore, may have provided an antigen producing specific immune response.     

Recruitment and effects of Discocotyle sagittata (Monogenea) infection on farmed trout

Farmed rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta were monitored over 3 years for infection with the blood-feeding gill fluke Discocotyle sagittata. Parasite transmission is seasonal: new infections take place during summer/autumn, and transmission is generally negligible during winter/spring. There are 2 sources of infection for naïve fish-of-the-year: limited invasion when fish are in the raceways by riverborne larvae originating external to the farm; and internally, within the farm, when 0+ fish are transferred to ponds previously occupied by older cohorts of infected fish. Thereafter, infection levels continue to increase in rainbow trout primarily through transmission within the farm. Prevalence rose to 100% in 1+ fish by the end of their second summer. In O. mykiss, mean abundance reached 194 worms/host for 1+ fish (up to 489 worms/host) and 160 worms/host for 2+ fish. By contrast, in S. trutta, parasite prevalence never exceeded 85% and, after the first year's invasions, infection levels decreased over time: in 1+ and 2+ brown trout, parasite mean abundance was < 4 (maximum 15) worms/host. We present evidence of the detrimental effects of D. sagittata on the host: high burdens are associated with pale gills, decreased body condition and host mortality. Parasite burdens become overdispersed during the warmer part of the year, as prevalence and mean abundance increase. However, the degree of parasite overdispersion decreases over winter; we cannot distinguish whether decreased aggregation is due to parasite losses from infected fish (including immune-mediated parasite mortality) or parasite-induced host mortality.     

牙鲆抗病群体和家系的建立及其生长和抗病性能测定

通过自然选择和人工感染途径筛选出抗鳗弧菌病牙鲆鱼种,将其培育成亲鱼94尾,建立了牙鲆抗病群体;从日本引进了牙鲆日本群体;以上述2个群体以及黄海中捕捞的黄海群体为基础群体,通过不同组合的交配,建立了63个牙鲆家系,其中半同胞家系54个,全同胞家系9个.生长比较实验表明这63个家系的生长速度存在着明显差异,从中筛选出生长快速的家系4个(家系36,42,43和57),生长较快的家系9个(家系27、28、35、39、41、51、60、65和76),生长慢的家系1个(75号家系).通过对59个家系的抗病能力测定表明,不同家系在抗鳗弧菌感染的能力上存在着明显差别,从中鉴定出抗病力强的家系3个(家系50,61和68号),其在鳗弧菌感染后的成活率高达60%以上;抗病力比较强的家系17个,其成活率为39%～60%;抗病力一般的家系33个,其成活率为17%～39%之间;抗病力差的家系6个,其成活率在17%以下.这些牙鲆家系的建立为牙鲆抗病、高产新品种的培育奠定了重要基础.     

牙鲆和半滑舌鳎5S rDNA基因的染色体定位及鲽形目5种鱼类的分子系统学分析

利用荧光原位杂交(FISH)技术将5S rDNA基因定位在牙鲆和半滑舌鳎染色体上,结果表明,5S rDNA基因在雌、雄性半滑舌鳎的一对同源染色体上分别存在2个杂交信号位点;在二、三倍体牙鲆的同源染色体上分别存在2个和3个杂交信号位点,杂交信号明显且特异。本研究首次将5S rDNA基因定位在半滑舌鳎和三倍体牙鲆的染色体上,为牙鲆及半滑舌鳎倍性鉴定、染色体鉴别提供了有效方法。此外,根据牙鲆5S rDNA基因编码区序列设计引物,扩增出大菱鲆和半滑舌鳎5S rDNA基因编码区序列,与鲽、塞内加尔鳎、大口黑鲈、七鳃鳗的5SrDNA基因序列进行同源性比较后发现,5种鲽形目鱼类5S rDNA基因序列同源性高达98.3%,系统发生分析结果显示5种鲽形目鱼类聚为一支;各序列中GC含量均显著高于AT含量。     

Immobilization antigen-independent protection of olive flounder (Paralichthys olivaceus) against Philasterides dicentrarchi (Ciliophora: Scuticociliatia) infection

To determine whether olive flounder (Paralichthys olivaceus) immunized with lysate of Philasterides dicentrarchi could be protected immobilization antigen (i-antigen) type independently, fish were immunized with lysate of ciliates obtained from in vitro cultures or ciliates obtained from infected fish. Fish immunized with ciliates obtained from infected fish were completely protected against artificial infection with in vitro cultured P. dicentrarchi, in spite of a weak or no serum agglutination activity against in vitro cultured ciliates. The present results indicate that i-antigen-independent protection was elicited by immunization of fish with the ciliates lysate, and the cultured ciliates would provide a good source for preparation of vaccines, which are cross-protective against various i-antigen types of P. dicentrarchi.     

Diel rhythms of oxygen consumption rates of California halibut (Paralichthys californicus) under culture in a recirculating system

Diel oxygen consumption patterns were determined in this study for California halibut (Paralichthys californicus) 3.2, 4.4, 6.2, 7.5, 9.2, 11.8, 12.8 and 14.2 g and between 110.5, 113.8, 115.7, 117.9, 120.1, 126.5, 132.4, 140.6, and 165.6 g held under farm-like conditions. The concept farm-like refers to a fish rearing condition as close as possible to a farming operation in terms of density, loading, and daily management. Open respirometries were performed in culture raceways during 24 h cycles while fish were growing from 3.2 g up to 165.6 g to determine hourly oxygen consumption rates by mass balance calculations. Fish were offered feed continuously during 12 h (within the 16 h light phase) resulting in maximum daily oxygen consumption rates that were between 1.2 and 1.5 times the mean daily values. A typical diel oxygen consumption pattern of the smaller group of fish tested (range between 3.2 and 14.2 g) had a peak during the feeding period, and relatively low and falling oxygen consumption after feeding was stopped. Oxygen consumption of the larger group of fish (range between 110.5 and 165.6 g) showed a less marked diel variation and did not change significantly after feed was distributed. In conclusion, diel oxygen consumption rates for California halibut reported here are key bioengineering parameters to be used when designing and sizing a rearing facility for the intensive culture of California halibut.     

牙鲆趋化因子基因CXCL9的克隆、鉴定与表达分析

趋化因子是一类具有化学趋化功能的小分子分泌性蛋白,能够引导白细胞到损伤或者感染的部位,参与免疫调节和病理反应。为丰富鲆鲽鱼类趋化因子的相关基础研究,本研究克隆了牙鲆(Paralichthys olivaceus)趋化因子基因CXCL9,其全长为910 bp,开放阅读框为408 bp,编码135个氨基酸。该基因具有趋化因子超家族的典型特征,在35、37、60和77个氨基酸位置具有4个保守的半胱氨酸残基,形成两个二硫键。氨基酸序列分析表明,该基因与大菱鲆(Scophthalmus maximus)、半滑舌鳎(Cynoglossus semilaevis)的CXCL9基因具有较高的同源性,分别为78.5%和71.0%。实时荧光定量PCR结果显示, CXCL9在正常牙鲆肝脏和脾脏中的表达量非常高,在皮肤和鳃等组织中表达量次之,说明CXCL9特异性地在免疫相关组织中表达。经迟缓爱德华氏菌(Edwardsiella tarda)感染后,牙鲆肝脏中CXCL9 mRNA表达量在感染后6 h即出现高峰值,而头肾和脾脏中的高峰值出现较晚。经鳗弧菌(Vibrio anguillarum)感染后6 h,牙鲆肝脏中CXCL9 mRNA的表达量升高近8倍,头肾中的表达高峰值出现在感染后24 h,而脾脏中CXCL9 mRNA的表达量在感染后6 h迅速升高10倍,逐渐降低后48 h又出现高峰,为正常水平的20倍。上述研究结果说明CXCL9基因在病原菌感染过程中有快速响应,可能参与了免疫防御过程,将有可能发展为一种牙鲆细菌性疾病的生物标记。本研究为牙鲆趋化因子超家族免疫机制的深入研究奠定了基础。     

Investigating fragment size for culturing reef-building corals (Porites lobata and P. compressa) in ex situ nurseries

Culturing small propagules of coral has the potential for high yield with low environmental impact, provided that mortality is low. This study investigated the size-specific mortality and growth of minute fragments (as small as 5 polyps) of two of the most abundant reef-building corals in Hawaii (Porites lobata and P. compressa). Two ex situ nursery systems differing in cost, design complexity, and labor intensity were compared. The first nursery experiment lasted for four months in a large tank with high water motion/surge and extensive manual cleaning to remove competitive algae. The corals were then transferred to a simple low-flow tank containing sea urchins (Tripneustes gratilla) and reduced cleaning, where they were grown for six more months (Nursery II). ‘Nursery I’ resulted in 92% of P. lobata and 73% of P. compressa fragments surviving and nearly doubling in area, in spite of a brief infestation by a nudibranch (Phestilla sibogae) that primarily fed on larger P. compressa fragments. There was a significant positive relationship between fragment size and growth rate, and survivorship was significantly different between donor colonies (genets), but there was no evidence of size-specific mortality. ‘Nursery II’ on the other hand had clear size-specific mortality and higher urchin damage for smaller fragments, resulting in moderate survivorship (78% for P. lobata and 76% for P. compressa), and only a slight increase in the total area covered by coral tissue. Fragments larger than 3 cm² were undamaged and had the highest survival and growth rates. This study illustrates how size-specific mortality can be reduced by ex situ nursery conditions.     

Controlling the growth of a cyanobacterial contaminant, Synechoccus sp., in a culture of Tetraselmis chui (PLY429) by varying pH: Implications for outdoor aquaculture production

In aquaculture, large volumes of phytoplankton are often grown outdoors to reduce costs. However, growing microalgae in an environment not as well-controlled as in the laboratory can lead to unwanted phytoplankton, including cyanobacteria, contaminating a culture. A cyanobacterial contaminant was isolated from an outdoor culture of Tetraselmis chui (PLY429) at the Milford Laboratory. This study investigated the growth of PLY429 and the cyanobacterium in pure cultures and a mixed culture in a pH range of 6.5-9.5. The division of PLY429 was greater at a pH range of 7.0-8.0; whereas, for the cyanobacterium, higher growth was obtained at pH 8.0-9.0. Results from combined cultures of PLY429 and the cyanobacterium grown at various pHs indicated that maintaining pH near 7.1 yields higher growth of PLY429 than those of the cyanobacterium. These findings suggest that controlling pH may reduce the population of a cyanobacterial contaminant in an aquaculture feed culture.     

饲料中不同维生素A含量对花鲈生长和血清生化指标的影响

以酪蛋白和明胶为蛋白源,鱼油和豆油为脂肪源,糊精为糖源并添加氨基酸混合物配制精制基础饲料,通过向基础饲料中添加维生素A醋酸酯使饲料中的维生素A含量达到0、1 000、2 000、4 000、8 000和16 000 IU/kg(实测含量为245、1 005、1 835、3 781、7 583和15 273 IU/kg),配制出6种等氮等能的实验饲料(饲料1～6).以花鲈为实验对象,在室内流水系统中进行为期9周的生长实验,探讨精制饲料中不同维生素A含量对花鲈生长和血清学生化指标的影响.结果表明:摄食不添加维生素A组(饲料1)饲料的花鲈在养殖后期表现出较高的死亡率,并出现眼球浮肿、膨胀、鳍基充血以及鳃盖扭曲等维生素A缺乏症,而在其他维生素A添加组(饲料2～6)并未出现类似症状.体成分分析表明:饲料中不同维生素A含量会显著增加花鲈体脂肪含量,但对蛋白质和水分的含量没有显著影响.对花鲈血清指标分析表明:饲料添加维生素A含量会显著增加花鲈血清碱性磷酸酶(AKP)、甘油三酯(TG)和胆固醇(TC)含量,但显著降低丙氨酸氨基转移酶(ALT)和天冬氨酸氨基转移酶(AST)活力.采用折线模型,当以增重率为评价指标时,花鲈对饲料中维生素A的需求量为1 934.8 IU/kg;当以肝脏维生素A含量为评价指标时,花鲈对饲料中维生素A的需求量为3 546.6 IU/kg.     

Chicken-derived IgY recognizes developing and mature stages of Loma salmonae (Microsporidia) in Pacific salmon, Oncorhynchus spp.

A polyclonal IgY preparation, purified from yolk of immunized hens, is shown to be useful for the detection of Loma salmonae in Pacific salmon. Purity of the IgY was confirmed by SDS-PAGE and western blots of yolk protein extracts. Reactivity of the IgY preparation to L. salmonae was determined through indirect-fluorescent antibody tests on purified spores and by immunohistochemistry. Developing xenomas in histological sections of heart and gill tissue of infected chinook salmon (Oncorhynchus tshawytscha) were visualized as early as 4 weeks post-exposure (PE). Non-lethal detection of L. salmonae was obtained by indirect-fluorescent microscopy of acetone-fixed gill smears. The IgY preparation was shown to react with another Loma sp., L. branchialis. In contrast, no reactivity was observed with other microsporidian parasites of fish such as Pseudoloma neurophilia and Glugea anomala. Yolk derived IgY may be useful in the detection of other fish pathogens.     

Identification and characterization of a green-type mutant of Porphyra tenera Kjellman var. tamatsuensis Miura (Bangiales, Rhodophyta)

We identified two green-colored conchocelis strains of cultivated Porphyra, ‘Oba-green’ and HGT-6 (F₁ strain of ‘Oba-green’), based on PCR-RFLP and sequence analyses of the nuclear ITS region and the plastid RuBisCO spacer region. These molecular analyses confirmed that the two strains were green-type mutants of the endangered species Porphyra tenera, although their blade color was not green. Under the same culture conditions, blade length increase was significantly higher in HGT-6 than in a wild strain HGT-1 of P. tenera, and the blade shape of HGT-6 was extremely elongate compared with that of HGT-1. From the growth characteristics and ITS-1 sequence data, HGT-6 was confirmed to be a green-type mutant of P. tenera var. tamatsuensis, a vigorously growing cultivar. Although photosynthetic pigment contents were lower in HGT-6 than in HGT-1, total content of four major free amino acids was higher and the blade thickness was almost the same in HGT-6 and HGT-1. These results suggest that the green-type mutant HGT-6 has potential as breeding material for further development of Porphyra breeding.     

虾夷扇贝耐高温育种家系的建立与早期筛查

对于贝类选择育种,维系大量家系养殖设施的成本巨大,如果能在贝类早期发育阶段对生长、存活进行筛查,提前舍弃那些存活率低、生长慢的家系,将有助于节约家系育种的成本。本实验通过室内模拟升温,比较了10个稚贝期全同胞家系在不同温度下存活率的差异,并对这10个家系在自然海区的生长、存活进行了一周年连续监测。结果表明:在室内8、13、18和23℃4个温度梯度下,10个家系经蓄养15~20 d后,18和23℃实验组的稚贝存活率差异显著,其中A08和A09家系的存活率最高,即为提前筛选出的耐高温家系;经自然海区一周年养成后,存活的4个家系(A01、A03、A08和A09)的存活率分别为0.9%±0.1%、0.5%±0.1%、34.3%±3.5%和46.5%±5.3%,但家系间壳高差异不显著,表明家系生长与存活无明显相关性;而A08和A09为耐高温家系,这与室内稚贝期升温筛选的结果一致。本实验验证了高温是导致虾夷扇贝夏季大规模死亡的主要原因,并提供了一种在家系稚贝期进行耐高温性提前筛查的方法,将为虾夷扇贝耐高温品系的选育提供参考依据。