The populations of many seabird species have undergone large decreases in recent years and these have often been linked to variability in and reduced availability of their prey resources, which have resulted from either large-scale environmental changes or fishing. Seabird species have also been shown to be potentially good monitors of their environments and can be particularly useful in understanding change in ecosystems where lower trophic levels are not well monitored. The seas around the Prince Edward Islands (PEIs, including Marion and Prince Edward islands) in the southwest Indian Ocean are one such ecosystem. Since the mid-1990s, monitoring of penguins at Marion Island has formed part of South Africa’s contribution to the ecosystem monitoring programme of the Convention for the