Maurice Laurence, Le Croizier Gael, Morales G., Carpintero N., Guayasamin J. M., Sonke J., Paez-Rosas D., Point David, Bustos W., Ochoa-Herrera V. (2021). Concentrations and stable isotopes of mercury in sharks of the Galapagos Marine Reserve : human health concerns and feeding patterns. Ecotoxicology and Environmental Safety, 215, p. 112122 [10 p.]. ISSN 0147-6513.
Titre du document
Concentrations and stable isotopes of mercury in sharks of the Galapagos Marine Reserve : human health concerns and feeding patterns
Année de publication
2021
Auteurs
Maurice Laurence, Le Croizier Gael, Morales G., Carpintero N., Guayasamin J. M., Sonke J., Paez-Rosas D., Point David, Bustos W., Ochoa-Herrera V.
Source
Ecotoxicology and Environmental Safety, 2021,
215, p. 112122 [10 p.] ISSN 0147-6513
The human ingestion of mercury (Hg) from sea food is of big concern worldwide due to adverse health effects,
and more specifically if shark consumption constitutes a regular part of the human diet. In this study, the total
mercury (THg) concentration in muscle tissue were determined in six sympatric shark species found in a fishing
vessel seized in the Galapagos Marine Reserve in 2017. The THg concentrations in shark muscle samples (n = 73)
varied from 0.73 mg kg-1 in bigeye thresher sharks (Alopias superciliosus) to 8.29 mg kg-1 in silky sharks
(Carcharhinus falciformis). A typical pattern of Hg bioaccumulation was observed for all shark species, with
significant correlation between THg concentration and shark size for bigeye thresher sharks, pelagic thresher
sharks (Alopias pelagicus) and silky sharks. Regarding human health concerns, the THg mean concentration
exceeded the maximum weekly intake fish serving in all the studied species. Mass-Dependent Fractionation
(MDF, δ202Hg values) and Mass-Independent Fractionation (MIF, Δ199Hg values) of Hg in whitetip sharks
(Carcharhinus longimanus) and silky sharks, ranged from 0.70‰ to 1.08‰, and from 1.97‰ to 2.89‰, respectively. These high values suggest that both species are feeding in the epipelagic zone (i.e. upper 200 m of the
water column). While, blue sharks (Prionace glauca), scalloped hammerhead sharks (Shyrna lewini) and thresher
sharks were characterized by lower Δ199Hg and δ202Hg values, indicating that these species may focus their
foraging behavior on prey of mesopelagic zone (i.e. between 200 and 1000 m depth). In conclusion, the
determination of THg concentration provides straight-forward evidence of the human health risks associated
with shark consumption, while mercury isotopic compositions constitute a powerful tool to trace the foraging
strategies of these marine predators.
Capsule: A double approach combining Hg concentrations with stable isotopes ratios allowed to assess ontogeny
in common shark species in the area of the Galapagos Marine Reserve and the human health risks concern
associated to their consumption.
Plan de classement
Limnologie biologique / Océanographie biologique [034]
;
Pollution [038]
;
Nutrition, alimentation [054]
Description Géographique
COLON ARCHIPIELAGO
Localisation
Fonds IRD [F B010081324]
Identifiant IRD
fdi:010081324
