Jacksonville University, 2800 University Blvd. North, Jacksonville, FL 32211, USA.
Jacksonville University, 2800 University Blvd. North, Jacksonville, FL 32211, USA.
Aquat Toxicol. 2023 Aug;261:106641. doi: 10.1016/j.aquatox.2023.106641. Epub 2023 Jul 24.
Anthropogenic practices have increased metal contamination in marine ecosystems. Most sharks have long lifespans, occupy an important ecological position at the top of marine food webs, and can accumulate metals. However, reference levels of metal contaminants in the tissues of sharks, particularly, apex predators such as the white shark (Carcharodon carcharias), are lacking. In this study, concentrations of copper (Cu), cadmium (Cd), nickel (Ni), lead (Pb), silver (Ag), and zinc (Zn) were measured in the muscle tissue of white (n = 42) and tiger (Galeocerdo cuvier; n = 3) sharks. Metal exposure in various species, including sharks, has been correlated with increased oxidative stress. Therefore, the main objectives of this study were to assess metal accumulation and antioxidant enzyme activity (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)) in the muscle tissue of the population of white sharks and tiger sharks inhabiting the Western North Atlantic. The measured parameters were qualitatively compared between species. The small sample size of tiger sharks (collected from only one site) limited statistical analyses, therefore, white sharks were the primary focus of this study. Differences in tissue metal (Cu, Cd, Ni, and Zn) concentrations and antioxidant enzyme activities were detected based on collection site, with significant positive correlations between Cd and enzymes, SOD and CAT, and Zn and enzymes, SOD and GPx in C. carcharias. Differences in Ni concentration were detected based on sex, with females having higher Ni levels. Additionally, plasma osmolality was not correlated with tissue metal concentrations; however, osmolality decreased with increasing length in C. carcharias. This study is the first to report baseline levels of Cu, Zn, Cd, Ni, Ag, and Pb in muscle of North Atlantic white sharks and provides new insights into oxidative stress responses of these sensitive species to metal contaminants.
人为活动增加了海洋生态系统中的金属污染。大多数鲨鱼的寿命都很长，在海洋食物网的顶端占据着重要的生态地位，并且可以积累金属。然而，鲨鱼组织中金属污染物的参考水平，特别是像大白鲨（Carcharodon carcharias）这样的顶级掠食者，仍然缺乏。在这项研究中，测量了北大西洋白鲨（n = 42）和虎鲨（Galeocerdo cuvier；n = 3）肌肉组织中铜（Cu）、镉（Cd）、镍（Ni）、铅（Pb）、银（Ag）和锌（Zn）的浓度。各种物种（包括鲨鱼）的金属暴露与氧化应激的增加有关。因此，本研究的主要目的是评估栖息在北大西洋的大白鲨和虎鲨种群的肌肉组织中的金属积累和抗氧化酶活性（超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GPx））。对物种间的测量参数进行了定性比较。由于只从一个地点收集到少量的虎鲨样本，限制了统计分析，因此本研究主要关注大白鲨。基于采集地点，检测到组织金属（Cu、Cd、Ni 和 Zn）浓度和抗氧化酶活性的差异，在 C. carcharias 中，Cd 与酶、SOD 和 CAT 以及 Zn 与酶、SOD 和 GPx 之间存在显著正相关。根据性别检测到 Ni 浓度的差异，女性 Ni 水平较高。此外，组织金属浓度与血浆渗透压无关；然而，在 C. carcharias 中，渗透压随体长的增加而降低。本研究首次报道了北大西洋大白鲨肌肉中 Cu、Zn、Cd、Ni、Ag 和 Pb 的基线水平，并为这些敏感物种对金属污染物的氧化应激反应提供了新的见解。
