The marine environment in the southeast region of Australia is generally highly biodiverse, with predictable upwelling events contributing to the productivity of the region during the warmer months. Key species of the region include 22 threatened marine species, as well as 19 species of fish and 7 species of invertebrates that are consistently targeted by commercial fisheries (Butler et al., 2002). Key threats of concern to biodiversity of the Bonney Upwelling and adjacent areas are any processes that may affect the upwelling itself, or that may directly affect whales and other marine fauna.
A number of cetacean species other than blue whales utilise the waters of the Bonney Upwelling at varying times of year. Our aerial surveys have sighted southern right, pygmy right, fin, sei, minke, humpback, sperm, long-finned pilot, killer, southern bottlenose, and Shepherd’s beaked whales, as well as common, bottlenose (two species), Risso’s and southern right whale dolphins (Gill et al., 2015).
Australian and New Zealand (long-nosed) fur seals also inhabit the region year-round, as well as a long list of seabirds, some of them resident, such as Australasian gannets and little penguins, and many of them migratory, including short-tailed shearwaters, black-browed albatrosses and Arctic skuas.
Blue Whale Study has always gathered data on species diversity whilst undertaking blue whale studies, and we are very interested in the use of the upwelling by species other than blue whales. During recent years, humpback whale sightings appear to have increased significantly across much of the year. This is hardly surprising as humpbacks migrating along Australia’s east and west coasts have increased spectacularly in recent decades as their populations recover from whaling. Humpbacks have been sighted feeding on krill near Portland and should now be regarded as a potential competitor with blue whales for krill. This is an interesting situation in which a species that has recently been taken off the threatened list could potentially pose an ecological threat to a species that remains well and truly on the threatened list. In any case Blue Whale Study now includes humpbacks in our ecological studies, to attempt to monitor trends in humpback occurrence and behaviour, and interactions between these two iconic species.
Butler, A., F. Althaus, D. Furlani, and K. Ridgway. 2002. Assessment of the conservation values of the Bonney upwelling area. A component of the Commonwealth Marine Conservation Assessment
Program 2002-2004. Report to Environment Australia.
Gill, P.C., R. Pirzl, M.G. Morrice and K. Lawton. 2015. Cetacean diversity of the continental shelf and slope off southern Australia. Journal of Wildlife Management 79(4):672–681; DOI: 10.1002/