Nonfiction

Drawn to Science – Triple Jeopardy in the Kimberley

23 March 2015

Sifting through fish guts, collecting ear bones and spotting crocodiles – it’s all in a day’s fieldwork for one postgraduate student from the School of Biosciences.

The Researcher

Meet Matt Le Feuvre is a PhD candidate researching the extinction risk of freshwater fish in the Kimberley, a region in Australia’s tropical north-west.

And also meet one of his research subjects, the Mitchell gudgeon, a little fish only found a few kilometres either side of the awe-inspiring Mitchell Falls. Why does this gudgeon stay so close to home? And does this make it vulnerable to extinction? These are some questions keeping Matt busy.

Matt’s laboratory hums with the whir and slosh of 18 fish tanks. Each tank is home to a species of freshwater fish from the Kimberley. Grunters and rainbowfish tread water and peer out from behind PVC piping. Matt says each fish has its own character, “The one you pointed out is active and inquisitive whereas that guy over there just loves the corner of that tank. I’ve spent enough time with them of late to know their personalities”, he jokes. But Matt’s PhD has been anything but fishbowl research.

The Fishy Fieldwork

Alongside James Shelley, a PhD candidate studying the biogeography of Kimberley fish, Matt has spent a total of eight months surveying remote and spectacular parts of the Kimberley.

“We were living out of the back of a 4WD for up to a month at a time. We worked from sunrise to sunset: we set the nets, would go hook and line fishing, electrofishing, snorkelling, and use baited remote underwater video.”

It hasn’t all been smooth sailing though. Holes in the radiator, holes in the boat, and an incident that would make Bush Mechanics proud – when the trailer’s axle broke, Matt fixed it with two ratchet straps and one of his shoes. A freshwater crocodile has even bitten James … on his head.

“It’s non-stop”, Matt says. “But we’re in beautiful places, outdoors, doing fun things, so, while it’s tiring, it’s definitely worth it.”

The Kimberley

Incredibly, this is the most extensive survey of Kimberley fish to date. Matt and James have been the first visitors to some rivers in over 40 years. Matt says that very little is known about the endemic species of the region.

And it’s little wonder. The Kimberley region is twice the size of Victoria! The terrain is incredibly rugged; some rivers are inaccessible even by 4WD. So Matt and James have had to use other, rather enviable, means of transportation. “We’ve been really lucky to charter some helicopters to some remote parts of the Kimberley. It’s been a lot of fun”, he says.

A GoPro strapped to the bottom of the chopper captures the scenery: gorges, waterfalls and sandstone escarpments that are golden in the afternoon sun. “It’s stunning countryside”, Matt adds.

The Kimberley is also highly biodiverse – it is home to 50 of Australia’s approximate 250 known freshwater fish species. And 18 of these are endemic to the region. But many of these species may be at risk of extinction.

The Research

Currently, 16 per cent of Australia’s freshwater fish are listed as a threatened species by the Federal government and none of those are in the Kimberley. This is where Matt’s research comes in. He is assessing the conservation risk of Kimberley freshwater fish species by looking at how vulnerable they are to extinction.

Aside from collecting data about the species’ distribution and abundance, he also studies their diet, life history traits (for example, how fast they grow), when they reproduce and how long they live for. Matt then uses the ‘triple jeopardy’ theory.

Triple jeopardy says that a fish is particularly prone to extinction if it:

1. Has a small range (remember the Mitchell gudgeon).

2. Is not abundant where it is found.

3. Has specialised dietary, habitat, physiological or reproductive requirements.

The long-nosed sooty grunter is one example that is a prime candidate for the triple jeopardy theory – it’s range-restricted, seldom caught and exclusively carnivorous.

As a part of his research, Matt also tests each species’ response to climate change. These are tough fish – Matt has found some species surviving in waterholes with a water temperature of 40 degrees! But climate change will likely result in later wet seasons in the Kimberley, meaning fish could have an extra month baking in hot water. Add to this the constant talk of damming the region’s waterways and you can begin to understand the importance of Matt’s research.

Matt believes proactive conservation is necessary, particularly in the face of mounting pressures like climate change. He hopes his research will elevate the extinction-prone fish of the Kimberly to the Australian Government’s conservation list. He says this is so, “They can be preserved before they start to decline”.

But it’s not always exciting fieldwork in the impressive Kimberly. Matt is now busy in his lab – interesting work, sure, though slightly less appetising. “At the moment I’m looking at what the fish have been eating”, Matt tells me. How? “Picking through their guts.”

You can contact Matt Le Feuvre on mclefeuvre@gmail.com or visit his website at www.mattlefeuvre.wordpress.com.


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