'Remarkable', uncommon shark washes up on beach
MYSTERY surrounds this peculiar-looking shark species which washed up on South Ballina Beach.
Margaret Shannon posted a photo of the shark on a local Facebook group that helps people identify animals, and wrote: "Found this washed up on South Ballina Beach -- any ideas? A shark of some description, but it's tail and flippers were really long?."
Marine scientist Dr Daniel Bucher, from Southern Cross University, identified the shark as a relatively young adult thresher shark.
Dr Bucher said there were three species of thresher sharks caught in NSW, and he believed this one to be the bigeye thresher Aulopias superciliosus because of the groove on top of the head and the size of the eye.
"The most common one is the thin-tailed thresher, which has a more southern distribution," he said.
"Less commonly caught are the two more warm water species, and this looks like one of those."
"The bigeye thresher are mostly open ocean species but occasionally come close to shore."
Thresher sharks are protected under Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
Dr Bucher said the species was easy to identify because of the top edge of their tail fin that's longer than its body.
"There's no oceanic sharks that have a tail fin that big.
"Females give birth to two to four live pups that are sustained in the uterus by production of unfertilised eggs that they feed on.
"They are also remarkable in that they can keep the brain and eyes warmer than the surrounding water (as do several other oceanic sharks such as whites and makos).
"Bigeye threshers can grow to 4.9m, although that measurement includes the tail that accounts for nearly half the total length. They feed on schooling fish which they drive to the surface and stun with slaps of the tail.
"They are not considered a threat to humans."
All three species of thresher shark - common, pelagic and bigeye - are found in Australian waters, as well as tropical and temperate oceans around the world.