Genetic evaluation of an otter translocation program

The translocation of individuals from onepopulation to another is a common technique inwildlife conservation. However, the outcome oftranslocation programs is not always properlyevaluated and the relative contribution ofreleased individuals to the resident populationoften remains unknown. We used mitochondrialDNA and autosomal genetic markers to evaluatethe success of a translocation program ofEurasian otters (Lutra lutra) in Sweden.The program is regarded as successful becauseof subsequent population growths. Norwegianotters used for the restocking program could begenetically differentiated from Swedish otters.The releases took place at two sites. In anarea south of the first site, where 47 otterswere released, no genetic contribution of theintroduced animals to the population could beobserved and the genetic diversity was lowerthan before the releases. At the second site,the release of seven otters led to a change ingenetic composition of the resident population.The results of this study suggest that thegrowth of the otter population after therestocking may not be as dependent on thereleases as initially suspected. The geneticeffects of the translocations appear to berestricted to areas in the immediate vicinityof the release sites.