Trace element levels in foetus-mother pairs of short-beaked common dolphins (Delphinus delphis) stranded along the French coasts.

Centre de Recherche sur les Ecosystèmes Littoraux Anthropisés, UMR 6217 CNRS-IFREMER-Université de La Rochelle, Université de La Rochelle, 22 Avenue Michel Crépeau, 17042 La Rochelle Cedex, France.
Environment International (Impact Factor: 5.66). 12/2007; 33(8):1021-8. DOI: 10.1016/j.envint.2007.05.008
Source: PubMed

ABSTRACT Tissues of foetus-mother pairs of common dolphins (Delphinus delphis) stranded along the French coasts (Bay of Biscay and English Channel) were analysed for their Cd, Cu, Hg, Se and Zn contents. In the kidneys, foetal Cd levels were extremely low, and strong relationships between Cu and Zn suggested the involvement of metallothioneins since early foetal life. The results also indicated a limited maternal transfer of Hg during pregnancy since levels in the tissues of foetuses were below 1 microg g(-1) w.wt. However, hepatic Hg levels in foetuses increased with body length, and were also proportionate to maternal hepatic, renal and muscular Hg levels. Lastly, affinities between Hg and Se in tissues would participate in Hg neutralisation in both mothers--through tiemannite granules--and fetuses--through reduced glutathione--counteracting the toxic effects linked to the particularly high quantities of methyl-Hg to which marine mammals are naturally exposed.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The common dolphin is the second most abundant cetacean species in the North-east Atlantic, with a wide-ranging distribution and is, potentially, impacted by a wide variety of pressures and threats. To assess the conservation status of common dolphins in this region, it is essential to understand population structure, key drivers of population dynamics, key resources and the effects of stressors. In recent years, a number of studies have assessed population structure, distribution and abundance, life-history parameters, dietary requirements and the effect of stressors—especially those caused by anthropogenic interactions, such as incidental capture (i.e., by-catch) and pollutants. A full review of this work is presented, with particular focus on current and potential pressures and threats. Notwithstanding the recent research, due to the lack of baseline data (i.e., prior to human influence) on abundance and pregnancy rate and on historical direct and incidental capture rates, the actual conservation status of the North-east Atlantic common dolphin population is unknown. Current assessments of conservation status of the species are therefore reliant on recent data. However, these assessments are hindered by the lack of data on contemporary incidental capture rates in some fisheries and limited sampling in other fisheries, as well as large data gaps for other stressors. In addition, the numerous potential ways in which multiple and diverse stressors can interact remain poorly understood. This chapter provides an outline of a management framework and describes methods for future evaluation of conservation status through development of indicators focusing on not only population size and distribution but also mortality and condition. Recommendations for research and conservation actions are described.
    Oceanography and marine biology 01/2013; 51:193-280. · 11.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The main objective of this study was to evaluate the contamination by mercury (Hg), methylmercury (Me-Hg), cadmium (Cd), selenium (Se), zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) in dolphins stranded on the French Mediterranean coast. The distributions of these contaminants in the organs of dolphins have also been studied. Overall, contamination levels varied according to the following sequence: liver > kidney > lung > muscle, except for cadmium (kidney > liver > lung > muscle). Size and sex of animals were also considered. Young dolphins were less impacted with trace elements than adults, except for copper. Among the studied parameters, the most important appeared to be the size of mammals. In addition, in the case of mercury and selenium, the sex of mammals seemed to be also relevant. The correlations between the concentrations of trace elements suggest the existence of detoxification processes. Since 1990s, using dolphins for tracing marine pollution, a slight reduction in the burden of the considered trace elements could be noted.
    Open Environmental Sciences 11/2014; 8:35-48.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In order to evaluate the use of biopsy samples as non-destructive tool for assessing trace element concentrations in small cetaceans, the concentrations of 14 trace elements were determined in skin, blubber, liver and kidneys of four species of small cetaceans (i.e. common dolphin Delphinus delphis, harbour porpoise Phocoena phocoena, bottlenose dolphin Tursiops truncatus and striped dolphin Stenella coeruleolba), stranded and/or by-caught along the NE Atlantic Ocean coast between 2001 and 2008. Only Cu, Fe, Hg, Mn, Ni and Zn were above the detection limit of the instruments and showed recoveries satisfactory enough to be interpreted. Among these trace elements, Hg was the only one showing a significant correlation between concentrations in and those in liver and kidneys. In consequence skin and blubber can only be used as non-invasive monitoring tissues to investigate Hg bioaccumulation in internal tissues for cetacean populations.
    Marine Pollution Bulletin 09/2013; · 2.79 Impact Factor

Full-text (2 Sources)

Available from
Jun 1, 2014