Counts of Little Penguins Eudyptula minor in Port Phillip Bay and Off Southern Phillip Island, Victoria, 1986-1988

Abstract

Transects were run within Port Phillip Bay and off southern Phillip Island, Victoria, between February 1986 and November 1988 and Little Penguins Eudyptula minor counted. Details are given for group sizes and activities, and totals are considered in relation to the breeding cycle at Phillip Island. Numbers within Port Phillip Bay peaked between June and September, and in May and August off Phillip Island. Little Penguin totals within Port Phillip were negatively and significantly correlated with the number of birds coming ashore at Phillip Island, and with breeding indices there. Counts off the Island did not show such relationships. It is concluded that Little Penguins from Phillip Island complete their breeding, then moult, before moving into Port Phillip Bay. Most Little Penguins in Port Phillip Bay were seen in the eastern and northern areas sampled. This distribution, which complements that shown by banding and radio-tracking, may be related to availability of potential food species. Little Penguins may move into Port Phillip Bay when fish, particularly post-larval fish, are most abundant. Although food shortages have not caused major mortalities, increased commercial fishing has the potential to create problems. There is a need to monitor such harvests and to obtain better information on the populations of prey species.