三丁基锡生殖毒性的研究进展

有机锡化合物,特别是三丁基锡,广泛存在于环境中,对生物体以及生态环境存在着潜在的威胁。本文综述了三丁基锡对软体动物、鱼类和哺乳动物生殖机能的影响及其其可能的作用机制,指出了进一步的研究方向。     

Fecundity as a Basis for Risk Assessment of Nonindigenous Freshwater Molluscs

Abstract:  The most efficient way to reduce future damages from nonindigenous species is to prevent the introduction of harmful species. Although ecologists have long sought to predict the identity of such species, recent methodological advances promise success where previous attempts failed. We applied recently developed risk assessment approaches to nonindigenous freshwater molluscs at two geographic scales: the Laurentian Great Lakes basin and the 48 contiguous states of the United States. We used data on natural history and biogeography to discriminate between established freshwater molluscs that are benign and those that constitute nuisances (i.e., cause environmental and/or economic damage). Two statistical techniques, logistic regression and categorical tree analysis, showed that nuisance status was positively associated with fecundity. Other aspects of natural history and biogeography did not significantly affect likelihood of becoming a nuisance. We then used the derived statistical models to predict the chance that 15 mollusc species not yet in natural ecosystems would cause damage if they become established. We also tested whether time since establishment is related to the likelihood that nonindigenous mollusc species in the Great Lakes and United States would cause negative impacts. No significant relationship was evident at the U.S. scale, but recently established molluscs within the Great Lakes were more likely to cause negative impacts. This may reflect changing environmental conditions, changing patterns of trade, or may be an indication of "invasional meltdown." Our quantitative analyses could be extended to other taxa and ecosystems and offer a number of improvements over the qualitative risk assessments currently used by U.S. (and other) government agencies.     

贝类典型寄生虫病害

体内寄生的原生动物是海水养殖贝类最严重的病原生物之一，在国外已进行了比较系统的研究。本文比较详细地介绍了典型贝类体内寄生的原生动物病害，包括血细胞虫病、微细胞病、槌虫病、单孢子虫病、帕金虫病，对其分类的地位、形态结构、生活史、流行情况、危害机理等进行了论述，为我国贝类病害的研究和防治提供参考。     

运用盐充法测量双壳贝类的壳腔体积

以长牡蛎（Crassostreagigas）和紫贻贝（Mytilusedulis）为例,研究了以食盐为填充物（盐充法）测量贝类壳腔体积的测量方法,并运用“水容法”进行验证。对两种贝类的测量结果表明,两种方法测得的壳腔容积结果相近,均无显著性差异（P〉0．05）。但运用盐充法测量牡蛎壳腔体积是水容法效率的8．4倍,测量贻贝壳腔体积的效率是水容法的6．2倍。由此可见,运用盐充法测量双壳类的壳腔体积具有操作简便和高效的特点,可广泛应用于贝类生理、生态和环境科学等领域的研究中。     

Terrestrial Reserve Networks Do Not Adequately Represent Aquatic Ecosystems

Abstract: Protected areas are a cornerstone of conservation and have been designed largely around terrestrial features. Freshwater species and ecosystems are highly imperiled, but the effectiveness of existing protected areas in representing freshwater features is poorly known. Using the inland waters of Michigan as a test case, we quantified the coverage of four key freshwater features (wetlands, riparian zones, groundwater recharge, rare species) within conservation lands and compared these with representation of terrestrial features. Wetlands were included within protected areas more often than expected by chance, but riparian zones were underrepresented across all (GAP 1–3) protected lands, particularly for headwater streams and large rivers. Nevertheless, within strictly protected lands (GAP 1–2), riparian zones were highly represented because of the contribution of the national Wild and Scenic Rivers Program. Representation of areas of groundwater recharge was generally proportional to area of the reserve network within watersheds, although a recharge hotspot associated with some of Michigan's most valued rivers is almost entirely unprotected. Species representation in protected areas differed significantly among obligate aquatic, wetland, and terrestrial species, with representation generally highest for terrestrial species and lowest for aquatic species. Our results illustrate the need to further evaluate and address the representation of freshwater features within protected areas and the value of broadening gap analysis and other protected‐areas assessments to include key ecosystem processes that are requisite to long‐term conservation of species and ecosystems. We conclude that terrestrially oriented protected‐area networks provide a weak safety net for aquatic features, which means complementary planning and management for both freshwater and terrestrial conservation targets is needed.     

Not Knowing, Not Recording, Not Listing: Numerous Unnoticed Mollusk Extinctions

Abstract:  Mollusks are the group most affected by extinction according to the 2007 International Union for Conservation of Nature (IUCN) Red List, despite the group having not been evaluated since 2000 and the quality of information for invertebrates being far lower than for vertebrates. Altogether 302 species and 11 subspecies are listed as extinct on the IUCN Red List. We reevaluated mollusk species listed as extinct through bibliographic research and consultation with experts. We found that the number of known mollusk extinctions is almost double that of the IUCN Red List. Marine habitats seem to have experienced few extinctions, which suggests that marine species may be less extinction prone than terrestrial and freshwater species. Some geographic and ecologic biases appeared. For instance, the majority of extinctions in freshwater occurred in the United States. More than 70% of known mollusk extinctions took place on oceanic islands, and a one-third of these extinctions may have been caused precipitously by introduction of the predatory snail Euglandina rosea. We suggest that assessment of the conservation status of invertebrate species is neglected in the IUCN Red List and not managed in the same way as for vertebrate species .     

贝类病原性寄生虫种类

海水贝类养殖业的迅猛发展以及养殖品种的异地养殖越来越普遍，导致了贝类病原性寄生虫全球范围内的广泛传播，而寄生虫是贝类最大的病原生物。本文比较系统地列举了导致牡蛎、贻贝、蛤类、扇贝、鲍鱼病害的寄生虫各类及体内寄生原生动物分类地位，为我国贝类病害的研究提供基础资料。     

海洋贝类类立克次体的感染

类立克次体的感染可以引起海洋贝类病害的发生,并且有时会导致贝类的大规模死亡,成为在世界范围内影响海洋贝类养殖业发展的重要制约因素.本文首先从海洋贝类类立克次体的分类地位、宿主种类及地理分布、海洋贝类类立克次体及其包涵体的生物学特征、致病性、传播途径、检测与防治方法等方面进行了系统的阐述.文章提出对海洋贝类类立克次体进行研究的必要性,分析了研究的重点及难点,展望了此研究领域的发展趋势.