环境因子对菲律宾蛤仔吐出杂物的影响

在不同温度、盐度、pH和光照条件下,研究了4种因素对菲律宾蛤仔Ruditapes philippinarum快速净化的影响。结果表明:温度为15~20℃时,菲律宾蛤仔吐出杂物的速率较大,净化4 h后其吐出杂物的重量百分比达89.59%;盐度为25~30时,蛤仔吐出杂物的速率较大,净化4 h后其吐出杂物的重量百分比达88.4%;pH为7~8时,菲律宾蛤仔吐出杂物的速率较大,4 h后其吐出杂物的重量百分比达87.99%;菲律宾蛤仔处于黑暗条件时,其吐出杂物的速率较自然光照下大,4 h后其吐出杂物的重量百分比达85.92%。因此,快速净化菲律宾蛤仔的适宜条件应为:水温15~20℃,盐度25~30,pH为7~8,且选择黑暗条件下进行。     

蛤类寄生的鱼钩虫属形态学观察

采用活体观察和蛋白银染色法,对文蛤、青蛤、四角蛤蜊和菲律宾蛤仔寄生性鱼钩虫属内的种类进行了初步鉴定,并观察其基本形态学特征。从4种蛤中共鉴定出鱼钩虫属纤毛虫3种,即尖鱼钩虫、日本鱼钩虫和厚鱼钩虫,其主要形态学统计特征有一定差异,但不同种间都具有各自相对稳定的特征。日本鱼钩虫和厚鱼钩虫的感染率和感染强度均高于尖鱼钩虫,不同种鱼钩虫表现出较高的宿主专一性。     

A herpes-like virus infecting Crassostrea gigas and Ruditapes philippinarum larvae in France

Concomitant sporadic high mortalities were reported in June 1997 among batches of larval Pacific oyster, Crassostrea gigas, and Manila clam, Ruditapes philippinarum , in a French commercial hatchery. Histological observation showed the presence of cellular abnormalities in affected animals. Electron transmission microscopy revealed the presence of herpes-like virus particles in infected larvae of both bivalve species. Viruses observed in C. gigas and R. philippinarum are closely related with respect to ultrastructure and morphogenesis. They were detected simultaneously in both bivalve species larvae indicating possible interspecific transmission. Moreover, PCR analysis using oyster herpes-like virus specific primers allowed amplification of fragments of expected sizes for both bivalve species and demonstrated the presence of viral DNA. The PCR products obtained for both bivalve species and digested by restriction enzymes displayed the same patterns. These data suggest that the same herpes-like virus may infect larval oysters and clams.     

Herpes-like virus infections in hatchery-reared bivalve larvae in Europe: specific viral DNA detection by PCR

Periodic losses in oyster hatcheries are regularly reported in Europe. Herpes-like virus infections seem to play a key role. Polymerase chain reaction (PCR) was used to investigate the presence of herpes-like virus DNA in larval samples belonging to different bivalve species from different geographical origins. Seventeen samples of the 81 analysed appeared positive for the herpes-like virus DNA by PCR. These results confirm previous data indicating that herpes-like virus infections occur in commercial French hatcheries. Polymerase chain reaction positive results were also obtained for bivalve larval samples originating from Spain and the UK. The number of virus DNA positive samples depended on the primer pair used. The primer pair C2/C6 appears well adapted for herpes-like virus DNA detection because of processing ease and great sensitivity. Positive samples were observed in four bivalve species: Crassostrea gigas , Ostrea edulis , Ruditapes decussatus and Ruditapes philippinarum . Herpes-like virus DNA detection is reported in larval R. decussatus for the first time. Many samples in which viral DNA was detected by PCR correspond to larval batches presenting mortalities. Herpes-like viruses may be one of the causative agents of mortalities observed in bivalve hatcheries.     

不同温度与饵料浓度下菲律宾蛤仔的能量收支

在静水系统中测定了实验条件下菲律宾蛤仔(Ruditapes philippinarum)的摄食率、吸收率、耗氧率和排泄率等生理指标;研究了软体部干重、温度和饵料浓度对菲律宾蛤仔最小碳需求量(WMCR)和能量收支的影响;建立了不同温度及饵料浓度下菲律宾蛤仔的能量收支方程。结果表明：最小碳需求量随个体软体部干重的增加而增加,温度越高其增加速率越快;软体部干重对生长效率没有显著的影响。温度通过影响耗氧率而显著影响单位软体部干重的最小碳需求量。在9—22℃范围内,菲律宾蛤仔的生长余力(SFG)随温度和饵料浓度的升高而增加,在较低温度和饵料浓度下蛤仔的SFG均出现负值。在能量收支方程中摄食能随温度变化显著,而呼吸耗能随温度的变化不明显。     

菲律宾蛤仔苗种土池中间培育及越冬生产试验

利用26000m2(39亩)和31349m2(47亩)2个养虾池,分别移入在室内培育的菲律宾蛤仔壳顶后期幼虫和双水管稚贝各80亿粒和9.7亿粒,经土池中间培育、越冬后,共生产出2 000-3 000粒／500g幼贝7.9亿粒,成活率分别达到4.5％和4.3％。     

菲律宾蛤仔的生活史

本文主要采用室内人工催产和培育方法,连续观察菲律宾蛤仔自受精卵至蛤苗(壳长7毫米)各发育阶段的形态变化,并结合观察自然海区蛤苗生长发育的周年变化,详细而系统地描述菲律宾蛤仔的生活史.根据精子与蛤苗的形态观察,进一步证实了过去福建海水养殖的杂色蛤仔(Rudi tapes Variegota Sowerby),订正为菲律宾蛤仔(Ruditapes PhilippinarumAdams ＆ Reeve)是正确的。     

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。     

菲律宾蛤仔养殖水体中大肠杆菌安全限量的研究

研究了在不同大肠杆菌含量的养殖水体中菲律宾蛤仔对大肠杆菌的富集情况,结果是,菲律宾蛤仔对大肠杆菌的富集量随着大肠杆菌在养殖水体中含量的升高而增大,从而推导出富集量公式y=0.9254x2 17.366x-123.77。参照CAC、91/492/EEC和NSSP的标准,通过相关换算,再与国内标准进行对比,建议将菲律宾蛤仔养殖水体中大肠杆菌的安全限量定为≤70MPN/100mL,将供生食的菲律宾蛤仔养殖水体中大肠杆菌的安全限量定为≤14MPN/100mL。     

乳山湾菲律宾蛤仔可溶性氮、磷排泄及其与温度的关系

菲律宾蛤仔(Ruditapes philippinarum)取自乳山湾东流区金港养殖区,其壳长范围为2.86~3.21 cm。实验结果表明,温度为20℃时,菲律宾蛤仔氮的排泄率最大(11.381μg.h-1.ind-1),是其他温度组(10℃、15℃、25℃、30℃)的2~8倍。菲律宾蛤仔代谢产物中NH4+-N占总无机氮的88%~91%,NO3--N和NO2--N占总无机氮的比例很小,分别为5.74%~7.89%和2.11%~4.01%,表明菲律宾蛤仔是排氨动物,氮的代谢终极产物主要为氨。磷的排泄随温度的变化不是很明显,排泄的磷中DOP的量明显小于DIP,总体趋势是随温度的升高略有增高,其中TDP和DIP变化幅度完全一致,DOP变幅相对较小,但上述3种形态P的水平随温度变化与N相比要小得多。通过实验分析表明,20℃时菲律宾蛤仔氮的排泄率最高。