A research crew of 19 Australian and international roboticists, marine biologists and students converged on Whyalla last week to study the night-time camouflage habits of the giant cuttlefish.
The crew, led by American marine biologist Roger Hanlon from the Massachusetts based Marine Biological Laboratory, used an underwater robot to take pictures of the cuttlefish at night.
The Autonomous Underwater Vehicle (AUV) amassed over 50,000 still pictures of the sea floor around the Point Lowly Peninsula over six days.
Hundreds of those images are expected to include a camouflaged cephalopod or two.
“We are going to have a beautiful image set of these animals at night,” Mr Hanlon said.
“We are finding an unexpected and wonderful diversity of camouflage patterns.
“We learned that, at night, they stopped all the sexual shenanigans, they stopped signalling and they all go camouflage.
“The coolest thing of all is that each animal has to camouflage itself in its immediate surroundings, its micro-habitat, and each animal, no matter what surface they pop down on they are showing a very sophisticated, tailor made image of the area around them.
“That means they can see just as well at night as they can in the day, and it also means that their predators can see at night.
“That is a major finding.”
University of Sydney Robotocists Stephen Williams and Oscar Pizarro said the AUV is usually used for surveying the sea floor but there is increasing interest in using automated tools for research such as this.
“Essentially the AUV allows us to capture the night camouflage of the cuttlefish without disturbing them,” Mr Williams said.
The National Geographic Society provided the funding for the trip, allowing the research crew to use the AUV.
“It’s a pretty expensive piece of gear,” Mr Williams said.
Mr Hanlon said the camouflage method used by cephalopods is called ‘adaptive colouration’.
“We want to look at the bigger picture of why these animals have such a diversity of appearance,” he said.
“The cuttlefish are among the very best of the cephalopods when it comes to adaptive colouration.
“It is a model organism when looking at how these animals can move around a complex environment and camouflage themselves.
“It is their main defence, or their only defence against predators and it also allows us to learn something about visual predation.
“The cuttlefish have a very complicated eye.
“We are trying to understand how cuttlefish see the complex visual background and turn on the night camouflage.
“The research is about visual perception as much as anything else.”
Mr Hanlon discovered that at night, in black and white images the cuttlefish are extremely camouflaged, however in colour images, the colouration of the animal does not match exactly.
“In the day the cuttlefish take on all the necessary aspects of camouflage, pattern, brightness, texture and colour but at night they only achieve three - pattern, brightness and texture,” he said.
“What the research indicates is that the animals are either not capable of making the colour match at night or they don’t need to.”
University of Queensland marine biologist, Justin Marshall specialises in visual predation and has collaborated with Mr Hanlon on the project.
“We could not have done the project without our highly accomplished Australian collaborators,” Mr Hanlon said.
“We have had a really productive trip.
“The project has gone really well.
“Everyone did a great job and we got our data.”