Using molecular markers and PCB analysis to infer the origin of the otter (Lutra lutra) found on the Knardijk, The Netherlands, in 1998
lt is presumed that the otter (Lutra lutra) became extinct in the Netherlands in 1988. Since then much effo1t has been made to restore the freshwater habitat aiming for a return of this top-predator. In 1998 from the central part of the Netherlands an otter was reported as a traffic casualty. lt was not known if this individual was a rudiment of the original Dutch population or if it had escaped f om the European otter breeding programme. To infer its origin, samples were taken for PCB and DNA analysis. Microsatellite DNA analysis was used to study 81 oller samples from three populations in Europe and from the breeding programme, including this individual. Cluster analysis indicates that it is unlikely that this otter originated from the Dutch population and it was with high probability assigned to the breeding program me. The levels of PCBs found in the otter were in the sarne range as found in the last Dutch otters, but were also si mi lar to levels found in a two years old otter that was bom and died in captivity. This indicates that PCB levels are not always good indicators for discrimination between captive and wild otters.