Suchergebnisse

Organochlorine (OC) pesticides and the more persistent polychlorinated biphenyls (PCBs) have well-established dose-dependent toxicities to birds, fish and mammals in experimental studies, but the actual impact of OC pollutants on European marine top predators remains unknown. Here we show that several cetacean species have very high mean blubber PCB concentrations likely to cause population declines and suppress population recovery. In a large pan-European meta-analysis of stranded (n = 929) or biopsied (n = 152) cetaceans, three out of four species:- striped dolphins (SDs), bottlenose dolphins (BNDs) and killer whales (KWs) had mean PCB levels that markedly exceeded all known marine mammal PCB toxicity thresholds. Some locations (e.g. western Mediterranean Sea, south-west Iberian Peninsula) are global PCB "hotspots" for marine mammals. Blubber PCB concentrations initially declined following a mid-1980s EU ban, but have since stabilised in UK harbour porpoises and SDs in the western Mediterranean Sea. Some small or declining populations of BNDs and KWs in the NE Atlantic were associated with low recruitment, consistent with PCB-induced reproductive toxicity. Despite regulations and mitigation measures to reduce PCB pollution, their biomagnification in marine food webs continues to cause severe impacts among cetacean top predators in European seas. ; The research was conducted by the UK Cetacean Strandings Investigation Program (CSIP) and the Centre for Environment, Fisheries and Aquaculture Science (Cefas) under contract to the UK Department for Environment, Food and Rural Affairs (Defra) and the Devolved Governments of Scotland and Wales. Additional funding for toxicological analyses was provided by ASCOBANS under contract "SSFA2010-3" and by the Fundació Barcelona Zoo. The Gulf of Cádiz and Strait of Gibraltar samples collection were sponsored by Loro Parque Foundation, Fundación Biodiversidad, CEPSA and ECOCET Project (CGL2011-25543) and logistical support for sample sexing was provided by Laboratorio de Ecología Molecular, Estación Biológica de Doñana, CSIC (LEM-EBD). Samples from Galicia were obtained with the support of Direccion Xeral de Conservacion da Natureza-Xunta de Galicia, co-financed with European Regional Development Funds (ERDF/FEDER). S. Murphy was supported by a Marie Curie International Outgoing Fellowship within the Seventh European Community Framework Programme. R. de Stephanis and J. Giménez were supported by the Severo Ochoa Programme for Centres of Excellence in R + D + I (SEV-2012-0262). A. D. Foote was supported by a Lawski Foundation stipend. ; Peer reviewed