Searching for sea slugs

Scientists from Southern Cross University (SCU), NSW Department of Primary Industry (Fisheries), and the Museum and Art Gallery of the Northern Territory, will team up with underwater photographers this weekend (December 7-8) to conduct a census of sea slugs in the Port Stephens area.

The region is internationally renowned for its huge diversity of shell-less marine molluscs (sea slugs), which include the amazingly colourful nudibranchs.

This inaugural photographic census has been timed to coincide with a period of particularly high diversity, with divers currently encountering upwards of 25 species on a single dive at many sites. Dive teams will be awarded a point for every species they photograph, with extra points awarded for the best photos.

While the event is being presented as a competition to test the observation powers of members of the Combined Hunter Underwater Group, the data generated will help to formally document the biodiversity of the Bay.

“We suspect that the Nelson Bay region is an important biodiversity hotspot in eastern Australia,” Associate Professor Stephen Smith, from SCU's National Marine Science Centre, said.

“This still needs to be tested by comparing lists of species among different areas. The sea slugs, and especially the nudibranchs, are a great group to start with due to their popularity with divers and the fact that they are often highly visible.”

Sea slug specialist Dr Richard Willan, from the Museum and Art Gallery of the Northern Territory, who will help identify some of the more unusual finds, suggested that there were some other very good reasons for targeted citizen science research on sea slugs.

“Sea slugs make very good indicators of climate change because they are highly visible, have short lives, and are generally easy to identify,” Dr Willan said.

This message has been reinforced over the last two weeks with the discovery of an introduced species (pictured) that is gradually spreading south along the east coast.

While the scientists are wondering what other interesting species may be discovered, divers are busily honing their observation skills, and checking out the best dive sites to target, in a quest to be declared the winner of the inaugural Port Stephens Sea Slug Census.

Photo: Godiva quadricolor, an introduced sea slug that has very recently made its way to Port Stephens. Photo by Stephen Smith.