Survivorship of captive-bred and wild-caught reintroduced European otters Lutra lutra in Sweden Original Research Article

Eleven wild-caught otters from Norway and 25 captive-bred otters from Sweden equipped with radio transmitters were reintroduced in an area in south central Sweden between 1989 and 1992. The objectives of the study were to compare the survival rate in the two groups, and to examine possible factors associated with differences in the survival rate. The survival rate one year after release was 79% in wild-caught otters and 42% in captive-bred otters. In captive-bred otters the period between removal from their mother and their release varied from 5 to 98 days. The offspring with short separation release periods had a significantly higher survival rate than those with long separation periods.