Gagné F, Blaise C, Pellerin J, Fournier M, Durand M J, Talbot A
Fluvial Ecosystems Research, Aquatic Ecosystems Research Protection Branch, Environment Canada, 105 McGill Street, Montréal, Québec, Canada H2Y 2E7.
Environ Int. 2008 Jan;34(1):30-43. doi: 10.1016/j.envint.2007.06.010. Epub 2007 Sep 6.
The purpose of this study was to examine the impacts of anthropogenic activity on the health status of intertidal clam populations of the Saguenay Fjord and the St. Lawrence Estuary (Québec, Canada). Clams were collected during low tide at sites subject to direct contamination and at sites far from human activity. Clams were analyzed for tributyltin and dibutyltin total levels and toxic stress (glutathione S-transferase, gonadal lipid peroxidation and DNA strand breaks), immunocompetence (phagocytic activity, hemocyte count and viability), reproduction (gonado-somatic index, gamete maturation, and vitellogenin-like proteins), energy status (temperature-dependent mitochondrial electron transport, and gonad lipids), and individual status (age, condition factor, and growth index). These responses were compared against population characteristics such as live clam density, number of empty shells, and sex ratio. The results show that clam density decreased with distance from the estuary (high salinity level) to upstream of the fjord (low salinity). There was no clear relationship between the number of empty shells and distance or site quality. Clam density values corrected against distance were significantly correlated with hemocyte viability, phagocytic activity, mitochondrial electron transport (MET), DNA damage in gonad, and temperature-dependent mitochondrial electron transport activity. A canonical analysis of the various groups of biomarkers revealed that population metrics were more strongly related with immunocompetence, followed by energy status and temperature-dependent mitochondrial electron transport activity. However, toxic stress biomarkers were strongly associated with energy status and reproduction. This was further confirmed by non-linear modeling using adaptive artificial neural networks (genetic selection and back propagation learning paradigms), where the following parameters were able to predict population parameters with <20% error: gonad maturation and somatic index, MET (at 4 degrees C), gonad LPO, DNA damage, and phagocytic capacity. Intertidal clam populations were influenced by a distance gradient effect (salinity), where immunocompetence, in addition to energy status, was the strongest physiological parameter related to clam population metrics.
本研究的目的是考察人为活动对萨格奈峡湾和圣劳伦斯河口（加拿大魁北克省）潮间带蛤蜊种群健康状况的影响。在退潮时，于受直接污染的地点和远离人类活动的地点采集蛤蜊。分析蛤蜊的三丁基锡和二丁基锡总含量以及毒性应激（谷胱甘肽S-转移酶、性腺脂质过氧化和DNA链断裂）、免疫能力（吞噬活性、血细胞计数和活力）、繁殖（性腺-体指数、配子成熟和类卵黄蛋白原）、能量状态（温度依赖性线粒体电子传递和性腺脂质）以及个体状态（年龄、条件因子和生长指数）。将这些反应与诸如活蛤蜊密度、空壳数量和性别比等种群特征进行比较。结果表明，蛤蜊密度随着从河口（高盐度水平）到峡湾上游（低盐度）距离的增加而降低。空壳数量与距离或地点质量之间没有明显关系。针对距离校正后的蛤蜊密度值与血细胞活力、吞噬活性、线粒体电子传递（MET）、性腺中的DNA损伤以及温度依赖性线粒体电子传递活性显著相关。对各类生物标志物进行的典范分析表明，种群指标与免疫能力的相关性更强，其次是能量状态和温度依赖性线粒体电子传递活性。然而，毒性应激生物标志物与能量状态和繁殖密切相关。使用自适应人工神经网络（遗传选择和反向传播学习范式）进行的非线性建模进一步证实了这一点，其中以下参数能够以小于20%的误差预测种群参数：性腺成熟和体指数、4℃时的MET、性腺脂质过氧化（LPO）、DNA损伤以及吞噬能力。潮间带蛤蜊种群受到距离梯度效应（盐度）的影响，其中免疫能力以及能量状态是与蛤蜊种群指标相关的最强生理参数。
