Suchergebnisse

Climate change is predicted to have profound consequences for marine ecosystems. Due to the growing political and social drive to address its impacts, monitoring and mitigating climate change is a priority in marine policy in the UK. Cetaceans have been proposed as informative sentinel species for monitoring ocean health. Here, strandings data from four UK cetacean species were assessed for their use as a tool to aid policy makers monitoring climate change in marine environments. Data on stranded cetaceans were collected from 1990 to 2018 and differences in the proportions of stranded cold water adapted and warm water adapted species assessed using Generalised Linear Models (GLM), with 6-year periods and four regions of the UK included as explanatory variables. This modelling approach showed an increase in the proportion of stranded warm water adapted species over time across the UK and that differences in proportion of strandings between cold water and warm water adapted species can be detected between regions and 6-year periods, chosen as metrics to coordinate with reporting cycles for policy assessment needs. As such, these results show the potential for utilising strandings data to identify changing oceanic trends at the appropriate spatial and temporal scales for policy reporting in the UK. However, development of these analyses with a more detailed examination of these data at a finer resolution, incorporating other data sources, such as distribution trends and dietary stable isotope data, may be required before it is applicable as an indicator for trends in changes in climate.

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