International Coastal Research Center, Ocean Research Institute, The University of Tokyo, Otsuchi, Iwate, Japan.
Ecotoxicology. 2012 May;21(4):1260-71. doi: 10.1007/s10646-012-0881-8. Epub 2012 Mar 11.
In order to examine the ecological risk for organic pollutants in diadromous fish migrating between sea and freshwater, organochlorine compounds (OCs) were determined in the catadromous eel Anguilla japonica having marine, estuarine and freshwater residence life histories. The eels were collected in Japanese coastal areas. We also compared the OCs accumulation with the marine eel Conger myriaster, which has a similar life history as A. japonica in the marine environment. The ontogenic changes in the otolith strontium (Sr) and calcium (Ca) concentrations were examined along the life history transect to discriminate the migration type. There were generally three different patterns, which were categorized as 'marine residence' (spent most of their life in the sea and did not enter freshwater), 'estuarine residence' (inhabited estuaries or switched between different habitats), and 'freshwater residence' (entered and remained in freshwater river habitats after arrival in the estuary) according to the otolith Sr:Ca ratio. There were generally no correlations between OCs such as Dichlorodiphenyltrichloroethanes (DDTs), Hexachlorobenzene (HCB), Hexachlorocyclohexanes (HCHs) and Chlordanes (CHLs) accumulation and each biological characteristic such as TL, BW and age in A. japonica. A positive correlation between the lipid content and concentrations of OCs were found. Additionally, the concentrations of HCB, ∑HCHs, ∑CHLs and ∑DDTs in A. japonica were significantly higher than those of C. myriaster, associating with the higher lipid contents (14% on average) in the former than the latter eels (9% on average). A negative linear relationship was found between the otolith Sr:Ca ratios and concentration of each OCs in A. japonica. The ecological risk of OCs increase as the freshwater residence period in the eel becomes longer. It is clear that migratory histories and lipid contents directly affected OCs accumulation in the anguillid eels.
为了研究洄游鱼类在海洋和淡水之间迁移过程中的有机污染物的生态风险，我们对具有海洋、河口和淡水生活史的洄游鳗鲡 Anguilla japonica 中的有机氯化合物（OCs）进行了测定。这些鳗鱼是在日本沿海地区采集的。我们还比较了海洋鳗鲡 Conger myriaster 中 OCs 的积累情况，后者在海洋环境中与 A. japonica 具有相似的生活史。我们沿着生活史轨迹检查了耳石中锶（Sr）和钙（Ca）浓度的发育变化，以区分迁移类型。根据耳石 Sr:Ca 比值，通常有三种不同的模式，分别归类为“海洋居留”（大部分时间生活在海洋中，不进入淡水）、“河口居留”（栖息在河口或在不同栖息地之间切换）和“淡水居留”（进入并留在河口后进入淡水河流栖息地）。在 A. japonica 中，OCs 如二氯二苯三氯乙烷（DDTs）、六氯苯（HCB）、六氯环己烷（HCHs）和氯丹（CHLs）的积累与 TL、BW 和年龄等生物学特征之间通常没有相关性。发现有机氯化合物的浓度与脂质含量呈正相关。此外，A. japonica 中的 HCB、∑HCHs、∑CHLs 和∑DDTs 浓度明显高于 C. myriaster，这与前者比后者鳗鱼（平均 9%）具有更高的脂质含量（平均 14%）有关。在 A. japonica 中，还发现耳石 Sr:Ca 比值与每种 OCs 浓度之间存在负线性关系。随着鳗鱼在淡水中居留时间的延长，OCs 的生态风险增加。显然，洄游历史和脂质含量直接影响了鳗鲡中 OCs 的积累。
