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The western rock lobster is the source of Australia’s most lucrative single-species fishery, yet surprisingly little is known about where it likes to live.

Associate Professor Kimberly Van Niel and Dr Renae Hovey from The UWA Oceans Institute are using underwater cameras and statistical modelling to discover exactly what type of habitat the western rock lobster (Panulirus cygnus) prefers.

By shedding light on which areas are most important to the species, the research could eventually lead to a more sustainable lobster industry.

“We’re working on something that’s really cryptic,” says Professor Van Niel. “Little is known about its spatial ecology in terms of what habitat it likes, and how it uses different habitats in different ways.”

The western rock lobster’s complex and often deep-sea lifestyle make it a difficult species to study, she says. “A lobster starts its life as plankton, moving with the oceans currents. After several months they moult into the free-living puerulus stage and swim towards the coast, settling on inshore reefs,” Professor Van Niel explains.

“Nearing maturity, they begin to migrate to deep waters, beyond where we can see them. So it’s hard to study where they’re living, what habitats provide the best food and shelter, and how far out they go.”

Sea floor photos

Professor Van Niel and Dr Hovey are analysing three years of pot catch records from sites off the coast of Jurien Bay. By using autonomous underwater vehicles (AUVs) to take fine-scale photographs of the sea floor at these sites, they can then calculate the probability of finding lobsters in different habitats – whether it’s kelp beds, sand patches or reefs.

Subsequently, the team will analyse footage of the sea floor taken across a larger area. Using spatial modelling, they can then make projections about where the western rock lobster is likely to be distributed.

Dr Hovey says fine-scale sea floor mapping like this could benefit other species, too, by illuminating habitats that were previously invisible to scientists.

“We don’t know how much habitat is available to a lot of species – how much soft sediments and reef they have,” says Dr Hovey.

“So when it comes to setting up protection areas, you don’t know how much habitat you need to protect, or where to make these protected areas, or how many you need. The key is to understand the relationship between species and habitats.”

Caption:

The western rock lobster … this surprisingly ‘cryptic’ species represents about 20 per cent of the total value of Australia’s fisheries. (Photo: Department of Fisheries WA/Henrique Kwong)

Media references

Beau Gamble (UWA Oceans Institute) (+61 8) 6488 8116 / (+61 4) 39 699 675