Mercury levels in commercial mid-trophic level fishes along the Portuguese coast – Relationships with trophic niche and oxidative damage. (September 2020)

• Record Type: Journal Article
• Authors: da Silva, Joana M.; Alves, Luís M.F.; Laranjeiro, Maria I.; Silva, Andreia; Angélico, Maria M.; Norte, Ana C.; Lemos, Marco F.L.; Ramos, Jaime A.; Novais, Sara C.; Ceia, Filipe R.
• Is Part Of: Ecological indicators. Volume 116(2020)
• Publication Date: 2020-09
• Subjects: Biomarkers -- Stable isotopes -- Stress responses -- Sardina pilchardus -- Scomber spp. -- Trachurus spp.; SEAc Area of the standard ellipse -- SEAB Bayesian standard ellipse areas -- LPO Lipid peroxidation -- SIA Stable isotope analysis; Environmental monitoring -- Periodicals; Environmental management -- Periodicals; Environmental impact analysis -- Periodicals; Environmental risk assessment -- Periodicals; Sustainable development -- Periodicals; 333.71405
• DOI: 10.1016/j.ecolind.2020.106500
• Languages: English
• ISSNs: 1470-160X

Abstract

Highlights: Commercial fish as bioindicators of mercury levels in mid-trophic levels. Mercury levels in tissues were much lower than the limits set by European Union law. Mercury levels showed no relationships with oxidative damage. Trachurus spp. differed from S. pilchardus and Scomber spp. in trophic niche. Oxidative stress biomarkers showed differences between sampling areas and seasons. Abstract: Sardines ( Sardina pilchardus ) and mackerels ( Scomber spp. and Trachurus spp.) are amongst the most common fish caught along the Iberian coast for human consumption and, as mid-trophic level organisms, they constitute essential prey in the diet of several marine predators. Thus, the assessment of trophic ecology, contamination exposure, and stress responses in such organisms provides valuable information on the environmental health in the mid-trophic chain and the potential risks for consumers. This study aims to contribute for an integrative mercury assessment of the marine ecosystem by measuring stable isotopes, mercury levels, and oxidative stress parameters in five commercial fish species in the northeast Atlantic. Samples of muscle and liver were collected from a total of 116 individuals in two fisheries assessment surveys (Spring and Autumn) along the whole Portuguese coast. Mercury concentrations and stable isotope analysis ( δ 13 C and δ 15 N) were performed in the muscle, while oxidative stress parameters (lipid peroxidation and DNA damage) were measured in both muscle and liver. Mercury concentrations were found to be considerably lower than values recorded in previous studies and the limits set by the European Union law, which confirms the non-toxic status of these species along the Portuguese coast, concerning this harmful element. Interestingly, no differences were found among the three genera, despite clear differences in trophic niches. Still, mercury concentrations were significantly higher during Autumn than Spring, possibly due to upwelling events during the Summer. Moreover, no relationships between the mercury concentrations and oxidative stress parameters were found. Overall, this work provided an integrative mercury assessment of commercial fishes from the mid-trophic chain, particularly from pelagic (and neritic) regions in the northeast Atlantic, showing that mercury concentration in these species is low. However, it is important to note that this study focused on small- and medium-sized specimens (overall ranging from 13–25 cm in length), and thus higher concentrations of mercury may be present in larger fish due to bioaccumulation.