Effects of ice cover on the behavioural patterns of aquatic-mating male bearded seals

Abstract

We used vocalizations to examine the behaviour of male bearded seals, Erignathus barbatus, in relation to ice cover over 2 consecutive years. Site fidelity varied between males. Territorial males returned to the same display locations in successive years, whereas roaming males returned to the study area but not to specific display locations. Males did not vocalize under the land-fast-ice edge and were therefore limited by access to areas of drift ice and open water for the purpose of displaying. Between-year fluctuations in ice cover restricted the number of displaying males during the early part of the mating season in April. Decreased ice cover during May resulted in more males displaying, but the number of males declined in June irrespective of the continued decline in ice cover. Roaming males were not heard when the ice cover was more than 60%, whereas territorial males were present during all ice conditions. Yearly fluctuations in ice cover may alter the long-term mating success of individuals and predictably available display areas may be preferred to areas that are more likely to be enclosed by fast-ice in some years.