Crayfish tracking

Today I went into the field with a colleague of mine (Kat, who was on Totally Wild yesterday) to help her with her current research project. She’s investigating the ecology of the Lamington spiny crayfish up near Lamington National Park.

Lamington spiny cray
A Lamington spiny crayfish (Euastacus sulcatus). This one is animal number 11.

These crayfish can be quite large, and it’s been estimated that they can live for at least twenty years. During Spring almost all of the adult female animals at this particular site were “berried”, meaning they were carrying eggs (that look like little red berries) under their tail. Female crays carry the eggs in this manner until they hatch, then the babies remain under the tail for a bit longer

Adult female Laminton spiny cray
An adult female Laminton spiny cray. The red “berries” under her curled tail are her eggs.

To track their movements Kat has attached radio transmitters to some large crays, and has been tracking their activity for the last several months. Unfortunately (but not surprisingly) some of the transmitters have come off their hosts and are lost in the wilderness. Our aim today was to track them down and retrieve them. We found one. Underneath a very large boulder. The cray must have burrowed behind the boulder, where the transmitter was then dislodged. We can’t figure out how to get that one back without destroying the boulder. Anyone have an endoscope they’d like to lend to us?

Even though we weren’t looking for them, we saw about 8 crays. Generally you just see some white claws sticking out from under a rock.

Crayfish claws
The first sign of a cray is usually a pair of conspicuous white claws sticking out from under a rock

But we also saw a couple just walking around in rock pools. They seem to stay active all year round, even though the water temperature at these higher elevations can be quite chilly. The water temperature was about 17˚C two weeks ago, and was about 20˚C today. It must be much colder during the Winter thing.

A few months ago I had a run in with a baby cray.

Baby Lamington spiny cray
A baby Lamington spiny cray in defense mode. They’re pretty harmless at this size…

They draw you closer with their cuteness and smallness, then POW!

Attach of the killer cray!
…Or are they?!!??

On today’s trip I saw a number of reptiles. They were small skinks, and all but one were too fast for me. The one I did manage to catch was also the prettiest, which was quite convenient. I think it’s an unusual colour form of Saproscincus rosei, but I’m by no means a skink expert. I’m going to ask around and get an accurate ID. I contacted Steve Wilson of the Queensland Museum, who confirmed that it is the unusual colour form found only in female Saproscincus rosei specimens.

Skink from near Lamington National Park

Saproscincus rosei. This is an unusual colour form found only in females of this speces. (click pic to enlarge)

Closeup of head of skink from near Lamington National Park

Closeup of the head of a Saproscincus rosei skink caught in forest near Lamington National Park. (click pic to enlarge)

During January Kat will be intensively tracking her crays, both during the day and at night. I’m hoping to spend some time down there with her, and hopefully we’ll stumble upon some snakes too.

About Stewart Macdonald

I'm a wildlife ecologist living and working in Queensland, Australia. I spend most of my time in the bush finding and photographing wildlife.
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9 Responses to Crayfish tracking

  1. Kat says:


    Go crayfish! They are so beautiful. I wish i could hug them… but somehow i think i would lose a limb or two if I tried..

    Nice story Stew! Keep up the good work 😉


  2. Stephen says:

    Are you sure the animal is not JJ, and you’ve reversed the image?


    As usual, just delete :)

  3. Stephen says:

    Aaah, so 11 is JJ’s long lost mirror image identical brother.

    My apologies, I’ve missed a few episodes of “Crays of Our Lives”.


  4. Todd Walsh says:


    I’d like to find out more about Kat’s work, as I am surveying Astacopsis gouldi down in Tassie. Great pics, impressive cray too, hope to hear from you soon.

  5. Stewart says:

    Hi Todd,

    I’ll get Kat to contact you.

    Astacopsis… Now that’s a freakin’ big cray!


  6. Crusty says:

    Great shots Stewart. Would like to put the full size images on our site if that was possible?

    That picture of the gouldi is Todd holding on to it lol

  7. Peter Hieke says:

    Yesterday I counted 43 spiny cray on a day walk in the BinnaBurra area. None of those I picked up carried eggs. It is still too early, is’nt it?

  8. 43! That’s impressive, Peter! I’m not sure when they start carrying eggs.