Did you know sawfish are related to sharks?
When I took on this story for CSIRO’s Double Helix magazine I didn’t know much about sawfish at all.
Now I know they’re a type of ray. I know they use their saws to detect the heartbeats of their prey, and also to stun fish and defend against predators. And I know they used to live around the world, but are now endangered. How cool is it to be a science writer and learn all these things as part of my job!!!
Fishing up a huge surprise
It started out as just another fishing trip.
Lisa Smiler was using a handline in Wattie Creek, 900 kilometres south-west of Darwin, in the Northern Territory, when she felt that unmistakeable feeling: a bite on the end of her line!
“I thought it was a barramundi, or a catfish, or something,” Lisa says. Whatever it was, it was big.
“I was pulling the line, then my sister helped pull the line, and her partner pulled the line, all the way up to the edge of the river,” Lisa describes. “All of a sudden, my sister pulled up the nose part, and I said, ‘Oh no, I don’t want this fish, it’s freaky.’”
At 2.7 metres long, the fish weighed more than Lisa did. When she posted its picture on social media, Lisa set the scientific world alight.
According to Western science, Lisa’s sawfish is the first ever observed swimming so far inland—nearly 500 kilometres from the ocean!
But Indigenous knowledge says differently. Local rock art of a sawfish, or kunpulu, suggests Lisa’s ancestors had seen the fish already.
Ursula Chubb, a Gurindji ranger, monitors the rock art site. “When we go out on country trips with Elders, they talk about it, and I listen to them telling us stories,” she says. “It’s a very important fish from long ago, when our ancestors were living in this country.”
Lisa says she never dreamed she’d see a live kunpulu. “I’d just heard about the sawfish in the rock painting … I wasn’t thinking I would catch one.”
‘Kunpulu’ means ‘sawfish’ in Gurindji, and in other Indigenous languages too, even those spoken hundreds of kilometres from Gurindji country.
Dr Felicity Meakins has studied Indigenous languages for over 20 years. She says different words tell their own stories, and she uses these stories to learn about changes over time.
“You can use different languages to trace the path of the fish,” says Felicity.
“I would guess at some point this fish has appeared, and people have said, ‘This is a stranger in our country. What’s this?’ And they’ve asked more northern people…and that’s how that word kunpulu has been passed along.”
Solving the mystery
We don’t know when Gurindji people first saw sawfish, but with ochre samples from the rock art, we hope to be able to solve the mystery. Scientists have also taken DNA samples from Lisa’s sawfish, to help work out how many sawfish are in the river.
“We’re using Indigenous ecological knowledge and western knowledge to build up a picture of what’s happened with the sawfish,” Felicity says.
Sawfish once lived around the world but are now endangered. Baby sawfish are born in the ocean, at the mouth of rivers like the Northern Territory’s Victoria River or Western Australia’s Fitzroy River.
The pups swim upstream, spending years growing in the river before swimming out to the ocean. Adults can reach up to seven metres long.
My article was first published in CSIRO’s Double Helix magazine.