Marine benthic algae and associated invertebrates from Brush Island to Broulee Is., Batemans Bay, southern NSW

A project undertaken by The Royal Botanic Gardens Sydney and managed by Alan Millar.

In an effort to better understand the benthic (seabed dwelling) marine life of the coast of NSW, this project intends to explore, collect and comprehensively document the marine benthic algae (including calcified algae) and associated invertebrates of the seabed between Brush Island and Broulee Island, including the Tollgate Islands, off Batemans Bay. Because seaweeds act as an excellent host for invertebrates and small fish, either through offering physical protection among their fronds, or as a direct food source, this project also intends to identify all associated mobile invertebrates to discover whether any direct relationship between a given algal species and a group of invertebrates exists. The project will concomitantly record the animal biodiversity inhabiting the algal species, thus providing valuable information for further conservation of marine algal habitats. This research will exploit the taxonomic expertise of two major state institutions, the Royal Botanic Gardens Sydney and the Australian Museum. It will also lead to a better definition of marine biogeographic provinces and boundaries along this coast, identify areas with high biodiversity and thus high conservation status, discover new species and genera to science, thereby increasing biodiversity knowledge of the State, produce solid baseline information on the primary producers of the marine environment, and finally document calcified coralline algae that are responsible for binding large amounts of carbon as calcium carbonate.

The first expedition identified many sites (especially on the leeward sides of the islands of Brush, Tollgates, and Broulee) that appear to be high in species numbers and biomass. Thirty-four invertebrate samples from 32 different species of algae were collected. The marine invertebrate samples have been transferred to ethanol and will be painstakingly sorted and identified to species-level taxa at the Australian Museum over the next two years. Closer scrutiny of the Australian Museum’s database has shown that the Batemans Bay region has not been as thoroughly collected as was previously thought. These collections therefore will not only address the novel research avenues of algal-invertebrate associations, but also greatly assist in filling in large gaps in the Museum’s biogeographic coverage of the state. All animal species recovered in this project will be incorporated into the Museum’s permanent collections and recorded in the Marine Invertebrates electronic database; this effort will not only provide a permanent record of the algal biodiversity, but will make the data available for future projects designed to enhance the conservation of the marine environment. The marine plants are being preserved as herbarium pressings and as spirit collections. Vouchers are also being dried for DNA extraction.


Millar AJK (2003-4) Gracilaria hermonii sp. nov. (Gracilariaceae, Gracilariales), a distinctive species from the east coast of Australia. Taxonomy of Economic Seaweeds, Hawaii.

Woodford, J. (2002) Seaweed diggers unearth new life in ocean’s gardens. Sydney Morning Herald, Saturday, 2 November 2002, page 5.


Dr Alan Millar examining seaweeds discovered off the Tollgate Islands of Batemans Bay (photo: Andrew Meares, Sydney Morning Herald)

Dr Alan Millar surfacing after a dive at the Tollgates, Batemans Bay (photo: as above)

Dr Alan Millar examining the newly discovered species Gracilaria hermonii at the Tollgate Islands, Batemans Bay (Photo: as above).