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| | Tasmania's Freshwater Burrowing Crayfish |
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What are Burrowing Crayfish
The burrowing crayfish of the genus Engaeus (pronounced En-GAY-Us), found only in south-eastern Australia, are very specialised crayfish living in tunnel systems in muddy banks, seepages and peaty areas. While most freshwater crayfish live in flowing water, the burrowing crayfish live their entire life within their burrow systems, only venturing out occasionally at night and in damp, overcast conditions. As they are typically no longer free-swimming, many of the species have much reduced tails as can be seen in the picture above. Other features of the genus include a narrow body and, unique among Tasmanian genera, claws that open vertically rather than horizontally to the body, allowing for larger claws in the confined space of narrow tunnels.
Engaeus Life History
As all crayfish have gills under their carapace (shell), they are dependent on water to breathe. Typically the tunnels of burrowing crayfish reach down to the water table and over the summer period when the water table drops, they will follow it down through well established tunnels, sometimes to depths of 2-3 metres.
Burrowing crayfish generally eat decaying organic matter in the soil, such as rotting leaves and twigs but will supplement their diet with the occasional small worm or grub they come across.
All species of Engaeus construct characteristic ‘chimneys’ made from balls of mud placed at the entrance of their burrow. These may range from just a few mud pellets or a structure to 40 cm in height, but we don’t really know why they build them!
Over dry periods, they will often plug the chimney, possibly to retain moisture within the burrow.
Breeding takes place from spring through to early summer. During this period adult females can be found carrying eggs or new hatchlings under the tail, which is closed over them to form a pocket for protection.
Each species has slightly different habitat requirements so that although a couple of different species may be found on the one property, they will inhabit specific areas depending on water flow, soil type, vegetation and degree of habitat disturbance.
Living their lives underground makes the burrowing crayfish extremely difficult to study without disturbing them. As a result there is still much to learn on the life history and requirements of the different species.
Distribution of Engaeus
View the brochure to see a map showing where the Engaeus species are found in Tasmania. Whilst some species appear to be very robust and found over wide areas, others have very limited distributions.
To the west two of the robust species are E. fossor and E. cisternarius, extending from below Macquarie Harbour in the south west through nearly to Devonport on the north coast. In the east the most widespread is E. mairener found from Wesley Vale through to Mt William National Park in the northeast. In contrast our threatened species have very limited distributions and within these locations the natural environment is being impacted adversely by human activities.
Threatened Species
Photograph by Niall Doran
Of the 15 confirmed species of burrowing crayfish found in Tasmania, 13 are endemic and live nowhere else. Two we share with Victoria. The 5 threatened species of burrowing crayfish include:
Threats
All of our burrowing crayfish are being impacted to some extent by human activities but, due to the limited ranges and localities of these threatened species, these effects are magnified.
They are at risk due to:
Agricultural Processes
How we can help this Species
Ensure that if development work is being considered within the range of one of the threatened species, that advice is sought from DPIPWE before beginning work.
Assistance and Species Advice
Commonwealth and State agencies, and regional NRM groups have a strong interest in protecting and preserving these species and as such funding is often available to assist in providing protective measures and habitat remediation on private land.
Species Advice
Zoologist, Threatened Species Section, Biodiversity Conservation Branch, DPIPWE
GPO Box 44, HOBART TAS 7000
Phone: 03 6233 3627
Email: Phil.Bell@dpipwe.tas.gov.au
Central North Field Naturalists, 68 Dynans Bridge Rd, WEEGENA TAS 7304
Email: nlester@tassie.net.au
Assistance
NRM Cradle Coast, PO Box 338, BURNIE TAS 7320
Phone: (03) 6431 6285
NRM North, PO Box 7507, 49-51 Elizabeth St, LAUNCESTON TAS 7250
Phone: (03) 6333 7777
This brochure is available online or from the Threatened Species Section.
Contact: Threatened Species Section - Enquiries
Threatened Species Section
3rd floor, 134 Macquarie Street
(GPO Box 44 Hobart 7001)
HOBART TAS 7000
Phone: 03 6233 8759
Fax: 03 6233 3477
Email: ThreatenedSpecies.Enquiries@dpipwe.tas.gov.au
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Tasmania's Freshwater Burrowing Crayfish
(PDF: 410 KB / 2 pages)
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 |  Tasmania Online | Service Tasmania This page - http://www.dpipwe.tas.gov.au/inter.nsf/WebPages/LJEM-73J92W?open - was last published on 9 April 2013 by the Department of Primary Industries, Parks, Water and Environment. Questions concerning its content can be sent to Internet Coordinator by using the feedback form, by mail to GPO Box 44, Hobart, Tasmania, Australia 7001, or by telephone. Please read our disclaimer and copyright statements governing the information we provide on this site. A text version of this page is also available. | |
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