Persistent organic pollutants (POPs) in the blubber and liver of 27 bottlenose dolphins (Tursiops truncatus) stranded along the coasts of Canary islands from 1997 to 2011

Abstract

During the 20th century, grey seals were hunted almost to extinction in the southern Baltic Sea. Since the 1960s, the Baltic grey seal population has suffered from anthropogenic impacts such as persistent organic pollutants (e.g., PCBs and DDT), progressive habitat destruction. Since end of the 1990s, the stock of the grey seals in the Baltic Sea has increased from 10.000 animals to more than 24.000 (2011). Today, after a period of about 100 years of absence, the grey seal is observed again in the southern parts of the Baltic Sea. In Mecklenburg-Western Pomeranian the sightings of seals are monitored since 2007 by the Agency for Environment, Nature Conservation and Geology. In January 2012, a ranger counted 25 individuals in the Greifswald Lagoon, 16 grey seals on the island “Greifswalder Oie” and 10 grey seals on Kap Arkona/North Rügen. During late winter and early spring grey seals are feeding on herring in the eastern waters of the island of Rügen. During the last years an important new haul-out site was established around Erholmene in the Danish Baltic. The number of animals at this location during the moulting season has increased from 3 in 2007 to 250 grey seals in 2011. Further important haul-out sites are located at Rödsand near Gedser/Denmark, where up to 67 grey seals have been recorded, Måkläppen (460 grey seals) in Skåne and Utklippan (382 animals) in Blekinge/Sweden. The number of grey seals breeding in the southern Baltic is still very limited, although pupping has been documented every year since 2003 at Rødsand and Måkläppen with 1 to 5 pups each year at both locations.