Charlie Huveneers says diving with sharks is never boring. It’s a masterful understatement from the newly appointed shark ecologist at the Port Lincoln-based Lincoln Marine Science Centre.
Instead of the fear that sharks instil in most people, Dr Huveneers has admiration for the subjects of his research which involves underwater surveys, tagging and biopsy sampling. The tagging program also occurs on the surface where white sharks, more colloquially known as ‘white pointers’, are producing some fascinating insights into shark behaviour.
Dr Huveneers said a variety of acoustic and satellite-linked tracking devices are used to collect data on swimming patterns, residence times, migratory corridors as well as water depths and temperatures.
“The general goal is to develop an understanding of the way in which sharks interact with the fishing industry and, of course, improve beach safety as well,” Dr Huveneers said.
“Some of the sharks that we are studying are protected but are still caught as by-catch from fishing operations in South Australia. Trying to get a better understanding of where the sharks are, and how much time they are spending in a particular area will help us reduce these fishing interactions.”
“Sharks are very important players in the marine ecosystem. There have been some recent overseas studies that showed how the decline in shark numbers impacts other organisms lower in the food chain. For example, the over-fishing of large predatory sharks in Northwest Atlantic led to an increase of smaller sharks and rays. As a result, the enhanced predation from those on their prey was sufficient to terminate a century-long scallop fishery.
“Such an example really illustrates how the numbers of sharks can have major influences on the entire ecosystem and on the people relying on that ecosystem in a place like Port Lincoln.”
A day in the ‘office’ for Dr Huveneers could find him diving to survey numbers, tagging sharks like wobbegongs – which tend to make the task easier by lying motionless on the seabed – and taking small biopsy samples with a modified hand spear as other sharks swim past for later genetic analysis. He might also be dissecting sharks to increase the knowledge of basic shark ecology and biology, which is lacking for many species.
On the surface, other species including white sharks, are lured close to a boat and tagged using a modified hand spear or drawn onto a sling with a barb-less hook before having an acoustic tag planted internally into the stomach cavity or a satellite tag fixed to a dorsal fin.
Some of the results obtained in collaborations with WA Fisheries, CSIRO, and the Australian Acoustic Tagging and Monitoring System have surprised researchers.
“Some of these sharks cover huge distances. We’ve had a white shark tagged at Neptune Island, off Port Lincoln, that was detected by a receiver deployed on Ningaloo Reef located, in the north-west of Western Australia. That shark had swum nearly 4000 kilometres in about 40 days, a very large movement in a very small amount of time,” Dr Huveneers said.
“There are a lot of very exciting project opportunities in South Australia because there has not been a lot of shark research done previously. The Lincoln Marine Science Centre is a fantastic platform for shark research. There is one of the largest aggregations of adult white sharks on the doorstep at the Neptune Islands, and there are many major fishing operations based here in Port Lincoln. As a result, this Centre will provide great support for scientists and students studying sharks in the area.”
Dr Huveneers says people’s perceptions of sharks, particularly white sharks, can change with greater familiarity.
“White sharks are supposedly the most dangerous sharks in South Australian waters and some people doing a cage dive will start off very afraid. However, that initial fear often becomes admiration when they realise that the sharks are hardly noticing the cage and bait in the water, but swim around like any other animal and do their own thing in their own environment – and there is nothing to be afraid of,” he said.
Dr Huveneers role – which is jointly funded by Flinders University and South Australian Research and Development Institute (SARDI) through Marine Innovation SA – will also include lecturing in fisheries science and marine vertebrates at Flinders in the second half of the year.