UMR DECOD (Ecosystem Dynamics and Sustainability), IFREMER, INRAE, Institut Agro, ZI Pointe du Diable, Plouzané F-29280, France.
IFREMER, CCEM Contamination Chimique des Écosystèmes Marins, Nantes F-44000, France.
Aquat Toxicol. 2022 Jul;248:106207. doi: 10.1016/j.aquatox.2022.106207. Epub 2022 May 23.
Chemical contaminants are one of the causes of the ongoing degradation of coastal and estuarine nurseries, key functional habitats in which the juveniles of many marine species grow. As chemical contaminants can cause a decrease in the energy available and induce defence mechanisms reducing the amount of energy allocated to life history traits, quantifying their effect on the fitness of juvenile fish is key to understand their population-level consequences. However, these effects are primarily estimated experimentally or in the wild but on a limited number of contaminants or congeners that do not reflect the wide variety of chemical contaminants to which juvenile fish are exposed. To address this issue, we measured concentrations of 14 trace metal elements (TMEs) and bioaccumulative organic contaminants (OCs) in European sea bass juveniles (1-year-old) from three major French nurseries (Seine, Loire and Gironde estuaries). We tested the hypotheses that (i) levels and profiles of contaminants differed among studied nurseries, and ii) fish growth and body condition (based on morphometric measurements and muscle C:N ratio) were lower in individuals with higher contaminant concentrations. Multivariate analyses showed that each nursery had distinct contaminant profiles for both TMEs and OCs, confirming the specific contamination of each estuary, and the large array of contaminants accumulated by sea bass juveniles. Increasing concentrations in some TMEs were associated to decreased growth, and TMEs were consistently related to lower fish body condition. The effect of OCs was more difficult to pinpoint possibly due to operational constraints (i.e., analyses on pooled fish) with contrasting results (i.e., higher growth and decreased body condition). Overall, this study shows that chemical contaminants are related to lower fish growth and body condition at an early life stage in the wild, an effect that can have major consequences if sustained in subsequent ages and associated with a decline in survival and/or reproductive success.
化学污染物是导致沿海和河口育苗场持续退化的原因之一，这些育苗场是许多海洋物种幼体生长的关键功能栖息地。由于化学污染物会导致可用能量减少，并诱导防御机制，从而减少分配给生活史特征的能量，因此量化它们对幼鱼适应性的影响对于了解其种群水平的后果至关重要。然而，这些影响主要是通过实验或在野外进行估计的，但仅限于少数几种污染物或同系物，这些污染物或同系物并不能反映幼鱼所暴露的广泛的化学污染物。为了解决这个问题，我们测量了来自法国三个主要育苗场（塞纳河、卢瓦尔河和吉伦特河口）的 14 种痕量金属元素（TME）和生物累积性有机污染物（OC）在欧洲鲈鱼幼鱼（1 岁）中的浓度。我们检验了以下两个假设：（i）研究中的育苗场之间污染物的水平和分布不同；（ii）污染物浓度较高的个体的生长和身体状况（基于形态测量和肌肉 C:N 比）较低。多元分析表明，每个育苗场的 TME 和 OC 都有独特的污染物分布，证实了每个河口的特定污染情况，以及鲈鱼幼鱼积累的大量污染物。一些 TME 浓度的增加与生长下降有关，TME 与鱼类身体状况的下降呈一致相关。OC 的影响则更难以确定，这可能是由于操作限制（即，对混合鱼类进行分析）导致结果相互矛盾（即，生长增加，身体状况下降）。总体而言，这项研究表明，在野外的早期生活阶段，化学污染物与鱼类生长和身体状况下降有关，如果在后续年龄阶段持续存在，并与存活率和/或繁殖成功率下降相关，这种影响可能会产生重大后果。
