A greater understanding of shark senses may prevent sharks being accidentally killed in commercial fishing operations, according to a researcher at The University of Western Australia.
WA Premier's Research Fellow Winthrop Professor Shaun Collin said large numbers of sharks are taken as bi-catch: "By examining the sensory input to the brains of sharks, we hope to eventually develop ways to repel sharks from fishing gear and being needlessly killed. They occupy a vital part of our ecosystem."
Professor Collin, of UWA's School of Animal Biology and UWA's Oceans Institute is co-author of a paper "A conserved pattern of brain scaling from sharks to primates", published online in PNAS (Proceedings of the National Academy of Sciences of the United States of America), which outlines the findings of his international research group.
"Sharks represent the earliest jawed vertebrates and therefore hold an important place in the evolution of vertebrates' ability to centrally process information," Professor Collin said.
The researchers found variation in the size of the different sensory brain regions in sharks of different species. For example, areas receiving visual input were bigger in sharks living in shallow, brightly lit environments and feeding on moving prey. In these same species of sharks, brain areas dedicated to processing olfactory cues or smell and the detection of electric fields (electroreception) were smaller.
The group found close similarities between sharks and humans in the relative size (or scale) of the component parts with respect to the whole brain. "The relative scaling of each of the different brain regions appears to be very similar across vertebrates," Professor Collin said. "Interestingly the olfactory bulb (which receives olfactory input) appears to scale independently of other brain regions while those areas processing vision, electro-reception, memory and so on all scale in a similar way.
"There is therefore a conserved, or inherited, pattern of brain evolution between cartilaginous fishes (sharks) and primates and possibly other animals such as birds and other mammals."
The other members of Professor Collin's group are based in universities in Queensland, California, New York, Auckland New Zealand and Uppsala Sweden.