A basking shark, rarely seen in Australian waters, will be donated to scientists after it was caught by the Castella Rosa fishing trawler off Victoria’s south-west coast.
The 3,500kg, 6.5-metre shark was being dissected by staff from Museum Victoria on Tuesday after being pulled in by the trawler on Sunday afternoon at Portland.
The museum’s senior collections manager, Dianne Bray, said that although she would prefer the shark “alive and in the sea”, she was glad the owner of the trawler, who accidentally caught the shark in the Bass Strait, had donated it to science rather than discarding it.
The challenge would be figuring out how to transport the giant to the museum and then preserve it properly for research, she said.
“We’ve sent a team of five people from the museum down there, the artists and craftsmen who prepare models and make taxidermy specimens and retrieve whales and giant fishes,” Bray said.
“Because this one is so large, they will dissect it on the wharf as we have nowhere to preserve such a large animal, and they will bring back the head, fins, stomach content, vertebrae, and tissue and skin samples.”
Basking sharks are the second largest fish species in the world after the whale shark, growing up to 12 metres. Although they are a rare sight in Australia, they have been seen between Port Stephens in NSW and Busselton in Western Australia, including around Tasmania and off South Australia.
The species is more commonly found in the temperate waters of the northern hemisphere, where its conservation status is listed as vulnerable. Very little is known about the gentle and slow-moving sharks, which feed on plankton and jellyfish, and have thin, weak jaws lined with tiny, 2mm-long teeth.
Given the rarity of the shark in Australian waters it was an exciting addition to the museum, Bray said. Researchers from all over the world had already been in touch, including one who wanted to scan the shark’s brain.
“We have colleagues at the CSIRO in Hobart who are doing genetic analysis, and colleagues in South Australia who want to look at the vertebrae, and then we’ll work with researchers around world,” she said.
“We need to figure out how to preserve it, and our art preparators will also make a cast of the head and fins so we can make a model for exhibition purposes.”
The museum already has some minor basking shark material, including teeth and skin taken from a specimen caught in 1883. That shark was such an exciting catch at the time that it was “driven up and down Swanston Street during race week”, Bray said.
“There are [fewer] than 20 specimens across Australia so this is a fantastic opportunity and is also why we are so glad the skipper of the vessel is donating rather than discarding the shark,” she said.
“Adding to our collection of basking shark specimens will help to inform us about their biodiversity, where they’re distributed and how they change over time, and we now have more modern research techniques available to give us this information.”
A Flinders University shark researcher, Dr Charlie Huveneers, said it was hard to say what may have brought the shark to Victoria, or how many others might be in Australian waters.
“Sharks tend to have fairly large migrations, usually driven by food or, in some cases, mating,” he said.
“By preserving tissue samples for genetic analysis we may eventually be able to look at which population this shark may have come from, for example whether it is part of a population usually found on the eastern side of South America, or whether it may be part of a distinct population found in southern Australia.
“We won’t know until we do extensive population genetics on this species.”
