Abstract
Little penguins from Penguin Island were found to either dive to shallow depths of 1-5m or to depths of 8-10m. As they use coastal bays that are also used extensively for water-based recreation, we hypothesise that both the shallow and deep diving penguins can potentially be disturbed or injured by watercraft. TDRs were attached to six little penguins, and the dive patterns and activity were described for the shallow and deep diving penguins separately. Shallow diving penguins executed >1200 dives per day with average dive duration of 10 seconds and spent one third of their day at sea underwater. Almost two thirds of their dives were to depths within the top 2m. The deep diving penguins executed fewer dives but of longer duration and thus spent approximately half of their time at sea underwater. These penguins had longer post-dive recovery. All penguins travelled in the top 2m and could spend >20 seconds within this depth. Both groups spent periods of 3 minutes to more than one hour at a time on the surface. Little penguins dive when they are approached by boats, and results of autopsies of little penguins showed many had injuries that were likely to be caused by watercraft. Penguin Island is part of a rapidly growing region with increasing human usage of the coastal waters. We urge state and local government authorities to develop management strategies to ensure the survival of this population of little penguins.