Search

Swordfish (Xiphias gladius) is a major marine resource of high economic value to industrial and artisanal fisheries. As a top predator with a long lifespan, it is prone to accumulate high levels of contaminants. The bioaccumulation of a wide range of both legacy and emerging persistent organic contaminants was investigated in the muscle, liver and gonads of swordfish collected from the Seychelles, western Indian Ocean. The detection of all target contaminants, some at frequencies above 80%, highlights their widespread occurrence, albeit at low levels. Mean concentrations in muscle were 5637, 491 and 331 pg g−1 ww for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and perfluoroalkyl substances (PFASs), respectively. ∑BFR mean concentrations were far below, i.e. 47 pg g−1 ww. The data are among the first obtained for such a high diversity of contaminants in an oceanic top predator worldwide and constitute a benchmark of the contamination of Indian Ocean ecosystems. • Wide range of organic contaminants investigated in swordfish from the Seychelles • Major contaminants were chlorinated (OCPs, PCBs) and fluorinated (PFASs) compounds. • All contaminants at low levels in Indian Ocean compared to other oceans worldwide • Tissue-specific distribution driven by contaminant affinities to lipids or proteins • No difference in contaminant concentrations in male and female swordfish [ABSTRACT FROM AUTHOR]

[Display omitted] • Numerous OHCs detected at low levels but moderate to high detection frequencies. • Large inter-species differences in relative contributions of PCBs, OCPs and PFAS. • Highest levels of DDTs determined in the oceanic top predator species. • Herbivorous species characterized by a higher contribution of 3–4 Cl PCBs. • Long-chain PFCAs (≥ C 8) by far predominant in comparison to PFOS. [ABSTRACT FROM AUTHOR]

Tuna and billfish are large pelagic fish of ecological importance in open oceans. As top predators with a long lifespan, they are prone to exposure to various contaminants such as persistent organic pollutants (POPs) and contaminants of emerging concern. In this study, three pollutant families were investigated, including polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCPs) and perfluoroalkyl substances (PFASs), including perfluorooctane sulfonate (PFOS) and perfluorocarboxylic acids (PFCAs). Contamination was investigated in individuals from three tropical tuna species, namely bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis) and yellowfin (T hunnus albacares) tunas and the billfish swordfish (Xiphias gladius), collected from various areas of the western Indian Ocean (WIO) in 2013-2014. Contamination levels and profiles were examined in fish muscle, together with biological parameters (fish length / age, sex, lipid content) and ecological tracers (carbon and nitrogen stable isotopes). POP levels were low in all species in comparison to other locations worldwide, revealing a low impact of anthropogenic organic contaminants in the WIO. A predominance of OCPs (especially DDTs) versus PCBs was highlighted in all species; PFASs were predominant over chlorinated POPs in tunas. Among the studied PFASs, long-chain PFCAs were found to prevail over PFOS in all species. Organic contaminant profiles differed across species according to their foraging habitat; swordfish and bigeye tuna, which both feed in deep oceanic layers, showed similarities in their contaminant profiles. Geographically, the distinct DDT profiles of fish from the Mozambique Channel suggested an exposure to different DDT sources, in line with regional use of this insecticide and coupled with an extended residence time of fish in the Channel. To our knowledge, the data presented here are among the first obtained for legacy and emerging organic contaminants in various species of large pelagic predators from the WIO. • Occurrence of organic contaminants in tuna and swordfish from the Indian Ocean. • DDTs and PFASs were predominant in swordfish and tunas, respectively. • Long-chain perfluorocarboxylic acids dominated PFAS profiles. • Species sharing similar feeding habitats showed similar POP profiles. • Tunas from Mozambique Channel showed unique DDT profiles. [ABSTRACT FROM AUTHOR]