Distribution, movement, and estimated population size of killer whales at Marion Island, December 2000

We report here on some shore-based killer whale observations that were collected at several localities around Marion Island (46°54'S; 37°45'E) in a single day during their peak activity period around the island. Using island wide observational data we mapped the movement patterns of killer whales, which were restricted to the east coast and may be related to breeding and moulting aggregations of southern elephant seals found there. We estimated the killer whale population at Marion Island to be in the range of 25-30 individuals. Movement of individually identified pods between adjacent observation points suggested estimated swimming speeds of between 11.9 km/h and 14.44 km/h while patrolling along the Marion Island beaches. No diel activity pattern was evident. We stress the need for more data similar to that obtained in the present study in order to render observations and monitoring of killer whales from a single point on the island meaningful.