Influence of Water Allocation and Freshwater Inflow on Oyster Production: A Hydrodynamic–Oyster Population Model for Galveston Bay,Texas, USA

A hydrodynamic–oyster population model was developed to assess the effect of changes in freshwater inflow on oyster populations in Galveston Bay, Texas, USA. The population model includes the effects of environmental conditions, predators, and the oyster parasite, Perkinsus marinus, on oyster populations. The hydrodynamic model includes the effects of wind stress, river runoff, tides, and oceanic exchange on the circulation of the bay. Simulations were run for low, mean, and high freshwater inflow conditions under the present (1993) hydrology and predicted hydrologies for 2024 and 2049 that include both changes in total freshwater inflow and diversions of freshwater from one primary drainage basin to another. Freshwater diversion to supply the Houston metropolitan area is predicted to negatively impact oyster production in Galveston Bay. Fecundity and larval survivorship both decline. Mortality from Perkinsus marinus increases, but to a lesser extent. A larger negative impact in 2049 relative to 2024 originates from the larger drop in fecundity under that hydrology. Changes in recruitment and mortality, resulting in lowered oyster abundance, occur because the bay volume available for mixing freshwater input from the San Jacinto and Buffalo Bayou drainage basins that drain metropolitan Houston is small in comparison to the volume of Trinity Bay that presently receives the bulk of the bay's freshwater inflow. A smaller volume for mixing results in salinities that decline more rapidly and to a greater extent under conditions of high freshwater discharge. Thus, the decline in oyster abundance results from a disequilibrium between geography and salinity brought about by freshwater diversion. Although the bay hydrology shifts, available hard substrate does not. The simulations stress the fact that it is not just the well-appreciated reduction in freshwater inflow that can result in decreased oyster production. Changing the location of freshwater inflow can also significantly impact the bay environment, even if the total amount of freshwater inflow does not change.     

贝类帕金虫间接酶联免疫吸附测定法的建立

采用液体巯基醋酸盐培养基(FTM)培养贝类帕金虫,以其制备抗帕金虫的免疫血清,建立一种快速检测贝类帕金虫的间接酶联免疫吸附测定法(iELISA)。方法中理想的包被抗原数量为104/mL;帕金虫抗血清最佳工作浓度1:10 000;酶标二抗工作浓度为1:1 000;进行血清敏感性测定,其最低检出限为102/mL;阻断试验中的阻断率达86.77%;板内和板间变异系数分别为2.9%和3.21%。将该方法标准化后,对30份菲律宾蛤仔体内帕金虫进行检测,所得结果与用FTM方法得到的结果进行比较,后者灵敏度要高于前者,但是在检测时间上,前者在24 h内能够完成,而后者需要7 d。     

海产贝类帕金虫病害的研究进展

比较系统地介绍了国外贝类帕金虫病害的研究进展，包括帕金虫的分类地位、形态结构、生活史、检测方法、病理学、病害发生生态机理、防治技术与对策等。我国目前海产贝类病害越来越重，并且在发病贝类体内也检测到了帕金虫的存在。因此，系统阐述国外贝类帕金虫病害的研究进展，对我国海产贝类病害的研究，具有现实意义。     

温度盐度对菲律宾蛤仔帕金虫病害发生的影响

在实验室内进行了暖冬、海水温度和盐度对菲律宾蛤仔体内寄生帕金虫数量变化影响的实验,结果表明,在冬季高于自然海水温度的各实验组中菲律宾蛤仔体内的帕金虫含量要高于自然海水温度实验组,并且显示出菲律宾蛤仔体内过冬的帕金虫于春末和夏初当海水温度达到20℃左右时又出现明显增高趋势,导致菲律宾蛤仔的死亡率显著提高;盐度实验结果表明,在温度相同情况下,20～24的盐度是菲律宾蛤仔体内帕金虫的最适繁殖盐度.针对实验结果,提出了预防菲律宾蛤仔的帕金虫病害的一些生态养殖措施.