For videographer Andre Rerekura, seeing the critically endangered green sawfish for the first time was like finding the Holy Grail.
- Western Australia is one of the last strongholds for the green sawfish
- The elusive species is listed as critically endangered on the International Union for Conservation of Nature’s red list
- The unique toothy sawfish rostrum moves silently in the water when battering prey
Exmouth-based Andre Rerekura discovered the sawfish hunting in the shallows of a remote creek in north-west Australia.
Mr Rerekura and a group of friends had traveled by boat to Urala Creek on the eastern side of the Exmouth Gulf, which is about 50 kilometers by water from the coastal town.
The gulf is full of dugongs, fish and whales during their migration but the eastern side where water meets land is a 100-kilometre-long stretch of mangroves and algal flats teeming with life.
Mr Rerekura said the gulf’s east coastline was a labyrinth of creeks and mangroves.
“We were lucky enough later in the day one of the guys actually spotted a sawfish in the shallows feeding and cruising through,” Mr Rerekura said.
“That’s kind of like the Holy Grail for some of us. Because I suppose they’re quite rare.
“For us to come across that, we were pretty excited.”
At first, the group thought the sawfish was two or three meters long when they filmed it with a drone, but when a not-so-large mullet swam past they realized it might be a bit smaller than they thought.
“It shows the area is like a little nursery for these sawfish,” Mr Rerekura said.
A sawfish stronghold
Murdoch University post-doctorate researcher Karissa Lear travels up and down the West Australian coast studying sawfish and other elusive species.
She said the green sawfish in the video captured by Mr Rerekura was probably a juvenile and maybe less than one meter in length
“That means it’s been pupped … pretty recently. Sawfish give live birth like most sharks and rays. This one probably would have been born where we saw it,” Dr Lear said.
“They live there for maybe up to a year and then they start moving slowly into other creeks and river mouths and mangroves around there.
“It’s really special to know that one was probably pupped down there so some of those creeks are probably a nursery area for at least a few juveniles.”
Green sawfish can be found from north of Perth around the top end of the country and over to Papua New Guinea and Indonesia, but Dr Lear said WA was a particular stronghold for the species.
“We’re really lucky in Western Australia that we have a couple of species of sawfish but globally nearly all of those animals are critically endangered,” she said.
“Where we find the most sawfish in WA are those areas that are really remote and hard to get to.”
The Ashburton River, some 70 kilometers north of Urala Creek, is a major nursery for green sawfish.
Dr Lear said areas with human development sometimes meant altered ecosystems which might not benefit sawfish but where there were untouched stretches of Pilbara coastline there was lots of prey and healthy ecosystems for species to live.
“Keeping these remote areas that we do have in the Exmouth Gulf and all the way up the Pilbara is really important for species like sawfish and other threatened species as well that use those habitats,” she said.
“WA is pretty much the only place left in the world that we have what appears to be a healthy functioning population.”
New marine park to protect parts of the Gulf
The West Australian government has promised to protect select coastal and marine parts of the Exmouth Gulf.
The under-researched area was once touted for inclusion in the World Heritage listing of the Ningaloo Reef and ranges until political pressure left it out of the final submission from the state government.
There was development interest in the gulf including a port on its western banks and a salt operation not far from Urala Creek.
Both were under assessment by the Environmental Protection Authority.
Mr Rerekura said the Exmouth Gulf was a spectacular spot which was raw and untouched.
“You can tell It’s quite a special and unique place from the get-go really,” he said.
“You get humpbacks migrating through, you’ll have them nursing in the bay, dugongs feeding in the shallows … on the other side of the gulf is a bit more untouched again.
“You’ve got all these big algae flats you see in the background.
“You can see on the low tide it all starts filtering back. It seems like it’s fueling the mangrove area like a super intertwined delicate ecosystem.
“It’s perfect the way it is at the moment.”