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A simple animal with extraordinarily complex visual abilities could be the key to developing remote underwater cameras and robotic machines. The archerfish, found across the north of australia, can see so well both below and above the surface of the water that it can catch insects by spitting at them.

The significance of the archerfish’s specially adapted visual system is being investigated by UWA researchers in collaboration with the University of Queensland (UQ). Dr Shelby Temple, from UQ, and his co-authors, including UWA Premier’s Fellow Winthrop Professor Shaun Collin , recently published their latest findings into how the eyes of animals are adapted to different environments in Proceedings of the Royal Society .

“We are still asking when and how the archerfish developed its ability to see so well both above and below water and its ability to shoot jets of water so accurately,” Professor Collin said.

Dr Temple is also looking at the archerfish’s behavioural acuity, trying to find the smallest target at which it can successfully shoot.

“Seeing through the water column is visually very challenging,” Professor Collin said. “And the exciting part of this fish’s remarkable vision is that different parts of its retina are tuned to different regions of its visual field. While it is focusing on the insect, it is also able to scan for predators. They are amazing eyes for such a simple animal.

“The eyes of fishes have evolved to take advantage of their (micro)environment. Fishes have adapted to a whole range of environments from shallow water to deep sea, with very different light conditions placing constraints on the efficiency of the visual system.

“A fish such as the archerfish has highly-developed vision and colour discrimination for different visual functions. For example, the part of the retina used to detect insects above the water is tuned to discriminate objects against green foliage, while the part of the retina used to scan for predators below the water is tuned to detect objects where the light environment is very different. This ability to optimise vision in complex environments is what interests us the most, an inbuilt level of visual plasticity,” Professor Collin said.

“Visual plasticity or specialisations for specific (and often changing visual environments) may be one way to explain how bony fishes have managed to adapt to almost every aquatic environment on earth,” he said.

The research is expected to help understand visual capabilities across the animal kingdom, as well as to contribute, eventually, to the design of sensors for underwater vehicles and machines, so they can successfully navigate through a range of different light environments.

Photo by Shelby Temple.

From UWA News 17 May 2010