New insights from age determination on toxic element accumulation in striped and bottlenose dolphins from Atlantic and Mediterranean waters

Virginie Lahaye (1) , Paco Bustamante (1, 2) , Willy Dabin (3) , Olivier van Canneyt (3) , Franck Dhermain (4) , C. Cesarini (4) , Graham J. Pierce (5) , Florence Caurant (1)

1 CRELA - Centre de Recherche sur les Ecosystèmes Littoraux Anthropisés
2 LIENSs - LIttoral ENvironnement et Sociétés
3 CRMM - Centre de Recherche sur les Mammifères Marins
4 GECEM - Groupe d'Etude des Cétacés de Méditerranée
5 Department of Zoology

This study aimed at comparing toxic element (Hg, Cd) bioaccumulation in relation to age for bottlenose (Tursiops truncatus) and striped dolphins (Stenella coeruleoalba) from Mediterranean and Atlantic waters. Metal concentrations were also measured in selected prey to infer metal exposure through the diet. As expected, Mediterranean prey exhibited the highest Hg levels, probably as a consequence of the Hg enrichment of the Mediterranean Sea. Comparing the predators from each area and taking age into account, Mediterranean bottlenose dolphins displayed higher Hg levels than Atlantic dolphins (p = 0.032), whereas Mediterranean striped dolphins did not (p = 0.691). The consumption of Myctophid fish, which showed the highest Hg levels (105 ± 80 ng.g-1 w.wt.) among Atlantic prey, may explain the high Hg levels in the liver of the Atlantic striped dolphins and suggested a preferential offshore feeding behaviour in this area. Concerning Cd, no clear differences were found between geographical areas.

Mots clés: Stenella coeruleoalba; Tursiops truncatus; Mercury; Cadmium; Diet; Exposure; Stenella coeruleoalba

Domaines: Ecotoxicologie

Virginie Lahaye, Paco Bustamante, Willy Dabin, Olivier van Canneyt, Franck Dhermain, et al.. New insights from age determination on toxic element accumulation in striped and bottlenose dolphins from Atlantic and Mediterranean waters. Marine Pollution Bulletin, 2006, 52 (10), pp.1219-1230. ⟨10.1016/j.marpolbul.2006.02.020⟩. ⟨hal-00226358⟩