A long-term analysis of the age structure of otters (Lutra lutra) from eastern Germany

The objective of this study was to examine if the increasing number of road -killed otters in eastern Germany affects the age structure of the populati on over a period of 40 years. A sample of 1027 otter carcasses from eastern Germany that were collected mainly as roadkills (69%) between 1957 and 199 8 was used to reveal possible long-term changes in age and sex composition across regions Age determination was based on the analysis of cementum annu li of canines. The frequency of juveniles (age class I) amounted to 22%. Th is is considerably underestimated when compared with living populations. Th e greatest proportion of otters is represented by middle age class IV (52%) with a maximum age of 15 years. Contrary to the even sex ratio found in li ving otters from the study range, the present data revealed a significantly higher proportion of males (58%), especially in lower age classes (age cla ss I: 66%, age class II: 71%). Concerning the question on possible effects of increasing numbers of road-killed otters on the population structure, th ere is no indication of effects on the age structure over the study period. Moreover, there is no time-related difference or significant region-specif ic deviation between age compositions of the otter samples of seven differe nt regions. These results apply equally for both sexes There is currently n o evidence that an increased mortality affected the age structure of otters from eastern Germany.