Tim the Yowie Man heads to the Brindabellas in search of the elusive mountain crayfish

You can't blame her astonishment, but the upland bogs of the ACT high country is the unexpected domain of not one, but two species of mountain spiny crayfish, Euastacus Crassus and Euastacus Rieki. However, it's the latter, named after Canberra icon Edgar Riek OAM who passed away earlier this year, aged 95, that is the holy grail of today's expedition.

Although renowned as a Canberra district wine pioneer, Riek also made his name as an entomologist, working as a Principal Research Scientist at CSIRO from 1945 through to 1978, during which time he described over 50 species of freshwater crayfish. Although early on in his career, in 1956, he collected the first known specimen of Euastacus Rieki (Rieki) from near Mt Gingera, the ACT's second highest peak, he never got around to describing the crustacean, something Gary Morgan, another CSIRO boffin did in 1997, naming it in Riek's honour.

The purpose of today's alpine adventure is two-fold. Firstly, it's to pay homage to Riek (how many people have actually seen the crayfish named after him?), and secondly to discover more about the crayfish of our mountains.

It's over an hour's drive on winding dirt roads so it's mid-afternoon by the time the Yowie Mobile reaches my pre-arranged meeting spot high in the Brindabellas, where waiting for me are Matt Beitzel and Mark Jekabsons of the ACT Environment and Planning Directorate.

This column has joined both of these dedicated aquatic ecologists in the field before – Jekabsons while on the hunt for the critically endangered Northern Corroboree Frog (Pseudophryne pengilleyi) (Call of the Wild, February 18, 2012) and Beitzel while wielding an electrofishing rod in the Murrumbidgee River (Shocking Currents, June 7, 2013, , attempting to reduce carp numbers.

Both of those were daylight excursions, but today's field trip is expected to run long into the evening, which at this time of the year, and at this lofty altitude, means just one thing: freezing conditions. Brrr.

The aim of the pair's research, funded under an ACT Government Climate Change grant, is to unlock the mystery of how these creatures, which are though to only live in a handful of alpine bogs above 1500m in the ACT and across the border in NSW, live and breed.

"It's too early to tell if Rieki is currently at risk, but certainly it is the sort of species which is likely to be affected by climate change, as they require access to permanent water and require a temperature threshold they can't exceed without detrimental effects," explains Beitzel as, somewhat ironically, he pulls his beanie lower over his ears.

"We need to set the rest of the traps before it gets dark," cautions Beitzel, a sense of urgency in his voice, as he and Jekabsons set specially-designed traps in the deeper pools of water.

"We'll leave these out overnight and check them at dawn," explains Beitzel as he unrolls the last trap into a frigid pool of water, about knee deep.

Apart from trapping, the other method used to collect data on the Rieki is spotlighting, my chance to see a Rieki in the wild.

It's not quite dark enough to spotlight yet, so Jekabsons pulls his trusty billy and gas burner out of his backpack and Beitzel and I follow him out of the bog and across to a nearby high point. It's a cracking sunset over the wilds of the ACT, NSW and beyond into Victoria. What a spot for a sundowner, even if it is just billy tea.

Although I'm yet to eyeball a Rieki, the dead branches of snow gums reach skywards like giant cray claws. Heck, even the ominous clouds looming on the horizon look a little like a cray's claw.

Thankfully before my imagination runs too wild, the sun sets, and by torchlight we trudge back down the hill and wade into the bog. The temperature has already plummeted and a mountain mist has rolled in. Just as I'm starting to think that maybe I should have stayed at home, curled up in front of the open fire reading a book with Mrs Yowie, Beitzel tosses me a pair of gum boots, announcing, with a distinct smirk on his face, "OK Tim, it's now it's time to get wet.".

Great, there's no turning back now. So with chattering teeth, net in one hand and bucket in the other, it's with military procession that I follow Beitzel's squelching tracks into the first of several predetermined square plots of bog. As our torch light lances through the fog, we strain our eyes for signs of crays hidden in the mud.

"I've got one, I've got one!" I yell. However ecstasy soon turns to embarrassment as Beitzel reveals it's just the carapace of a Rieki, which I soon discover, like fools-gold in a creek bed, are scattered all through the wetland.

"The shells are the result of regular moulting or as a result of predation by birds and feral animals," explains Beitzel, adding, "the crays do fairly impressive gymnastics to get out of their old skin."

Back to the search.

"Don't worry, they are definitely here," says Beitzel pointing promisingly to the surrounding swamp which is pock-marked with dozens of burrows, some of which, according to Beitzel, extend "at least two full metres into the ground".

There are also smaller burrows, which Beitzel claims, "are either works in progress, or 'motel holes' so if they sun comes up or a predator shows up they dash off and hole-up for a night or two."

As keen as I am to spot a Rieki, I'm certainly not willing to put my hand down a so-called "motel-hole" to see if one has "checked-in" yet.

Thankfully I don't have to consider putting my hand down a burrow, for just as we splash into another pool of water, I catch a glimpse of one, at least I think I do.

It's got the tell-tale glint in its eyes, the flash of colour from its joints and a hint of movement.

No false alarms this time. Beitzel helps me scoop him up and into the bucket. Bingo!

When the bucket is full, we move to the dry edge where Jekabsons and Beitzel measure up their respective catches and record other observations. By no means the biggest, the specimen I scooped up has an occipital carapace length of 50 millimetres which results in a total body length of 12 centimetres or close to 18 centimetres with claws. Not bad for a clumsy novice with numb hands and frozen feet.

You'd think the crayfish wouldn't like the cold up here either. In fact, it's a bit of a mystery what the crays do in mid-winter, often submerged under a layer of snow.

"Tucked away in their burrows they probably feed on roots growing into their burrows from above," says Beitzel, whose research here has already uncovered some surprising results including that "the females carry their eggs over the harsh winter, hatching in late spring".

After another couple of hours traipsing through the icy quagmire, we finally finish the last plot. In total, we've caught, recorded and released 21 crays – "not bad" according to Beitzel.

It's time for your akubra-clad columnist to call it a night and head back down the mountain, leaving Beitzel and Jekabsons behind to sleep by the bog in their swags. With the temperature already below zero, I'm sure the cray traps won't be all that's encrusted in ice in the morning.

Back home just before midnight, I find Mrs Yowie throwing one last log on the fire. I hand her the stash of carapaces I've brought back for our kids show 'n tell at school, then settle back in my arm chair to raise a glass of Canberra wine to Beitzel and Jekabsons.

Gazing outside through our lounge room window it's a clear night, complete with a sky full of stars from where I'm sure Edgar Riek OAM is looking down approvingly.

Did You Know? Although awarded an OAM in 1996 for his services to viticulture and to entomology, Edgar Riek had a long and distinguished career in a wide range of other interests including, palaeontology, geology, biology, bacteriology, horticulture and trout fishing.

CONTACT TIM: Email: timtheyowieman@bigpond.com or Twitter: @TimYowie or write c/- The Canberra Times, 9 Pirie Street, Fyshwick. You can see a selection of past columns at: http://www.canberratimes.com.au/act-news/by/Tim-the-Yowie-Man-hvf8o

Double Clue: In a main street and made of tiles.

Degree of difficulty: Medium – Hard

Last week: Congratulations to Janette Ryan of Ainslie who was first to correctly identify last week's photo, snapped by Thomas Schulze on a recent geocaching adventure, "as a fishing sculpture on farmland on Kaveneys Road, near its intersection with Dog Trap Road, Jeir." Ryan, who just beat Noel Bentley of Braddon and Alicia Mostert to the prize regularly drives through Jeir and "has enjoyed seeing this fisherman since it first appeared a couple of months ago".

How to enter: Email your guess along with your name and address to timtheyowieman@bigpond.com. The first email sent after 10am, Saturday June 4, 2016, with the correct answer wins a double pass to Dendy cinemas.