Aix-Marseille University, CNRS/INSU, Toulon University, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, Campus de Luminy, 13288 Marseille, France.
Aix-Marseille University, CNRS/INSU, Toulon University, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, Campus de Luminy, 13288 Marseille, France.
Mar Pollut Bull. 2018 Feb;127:131-138. doi: 10.1016/j.marpolbul.2017.12.006. Epub 2017 Dec 6.
Pelagic sharks (blue shark Prionace glauca and shortfin mako Isurus oxyrinchus) caught by long-line Spanish and Portuguese fleets in the NE Atlantic, were sampled at Vigo fish market (Spain) for total mercury (Hg) analysis. Hg concentration in white muscle increased with size and weight in both species, but at a higher rate in shortfin mako than in the blue shark. No difference was found with sex, year and season. Spatial variation was observed in the blue shark with higher Hg values in the North of the Azorean archipelago, but not in the shortfin mako. These high-level predators are particularly susceptible to bioaccumulate contaminants (Hg) in their tissues (muscle). However, a significant positive relationship between Hg concentration and trophic level (δN) of individuals was observed only in the shortfin mako. Most sharks landed were juveniles which presented Hg concentration lower than the maximum limit allowed by the European Union (1mgkg wet weight) for marketing. However, concentrations above this threshold were most recorded in blue sharks larger than 250cm total length (TL) and in shortfin makos larger than 190cm TL, raising the question of the commercialization of large-sized individuals.
北大西洋西班牙和葡萄牙延绳钓船队捕获的远洋鲨鱼（灰真鲨 Prionace glauca 和短鳍灰鲭鲨 Isurus oxyrinchus）在维哥鱼市（西班牙）被取样，用于总汞（Hg）分析。两种鲨鱼的白色肌肉中的汞浓度随大小和体重的增加而增加，但短鳍灰鲭鲨的增加速度高于灰真鲨。性别、年份和季节没有差异。在灰真鲨中观察到空间变异，亚速尔群岛北部的 Hg 值较高，但在短鳍灰鲭鲨中则没有。这些高级掠食者在组织（肌肉）中特别容易生物积累污染物（Hg）。然而，仅在短鳍灰鲭鲨中观察到 Hg 浓度与个体营养水平（δN）之间存在显著正相关关系。上岸的大多数鲨鱼都是幼鱼，其 Hg 浓度低于欧盟（1mgkg 湿重）允许上市的最高限量。然而，在灰真鲨中，记录到超过这一阈值的浓度主要是在全长（TL）超过 250cm 的个体和 TL 超过 190cm 的短鳍灰鲭鲨中，这引发了对大型个体商业化的质疑。
