Australian Aquatic Biological

Australian aquatic biodiversity research and consultancy

Central Highlands Burrowing Cray Engaeus affinis (Smith & Schuster 1913)

Engaeus affinis from a communal burrow, Healesville, Vic

Engaeus affinis from a communal burrow, Healesville, Vic

This species is endemic to Victoria with a relatively small distribution known at this time (estimated extent of occurrence of approximately 200 km2). Found in the upper Yarra, Acheron, Yea and Big Rivers. An area roughly from Kinglake to Eildon to Jamieson to Noojee to Hoddles Creek. Central Highlands Burrowing Cray Engaeus affinis has been assessed on the IUCN Red List as Data Deficient. 

Engaeus affinis, Healesville, Vic

Engaeus affinis, Healesville, Vic

It’s a robust species and at many sites relatively abundant. Typically, it’s a communal burrower, both type 2 & 3 burrows with multiple surface entrances (20 or so) over a square metre. Both fans shaped entrances and chimneys. Surface openings descend into large central burrows. Central burrows are relatively large in diameter (150 to 200 mm), typically water filled and tending horizontal and descending and converging into a larger chamber.

Engaeus affinis, Badger Creek, Vic

Engaeus affinis, Badger Creek, Vic

Typically, the easiest way to capture is to excavate down to the water level, usually from 200 to 600 mm deep. Once water is found, wait, (patience required), larger males will come to investigate the disturbance and you can grab them, otherwise, every 5 minutes or so, shove your hand down the burrow and feel around in the water. If you are lucky and have good feeling in your fingers you should be able to grab one every 5-10 minutes. That’s the way we collected the specimens for this article.

Burrow entrance, Badger Creek, Vic

Burrow entrance, Badger Creek, Vic

Those from Healesville were in a yellow clay on the slope beside a creek approximately 1.2 metres above the creek water height (7 metres from creek bank) but had water at 650 mm in the burrow system. Those from Badger Creek were in a fine silty material in a seepage area in the tree fern forest with water only 100 mm below ground level and over 100 m from Badger Creek.

Engaeus affinis, Badger Creek, Vic

Engaeus affinis, Badger Creek, Vic

Happy Yabbying

Cheers

Rob

Lowland Burrowing Crayfish Engaeus quadrimanus

Also known as “The Mernda Land Yabby” Engaeus quadrimanus (Clark 1936) is a relatively widespread and locally abundant species. It’s a lowland species generally found under 250 m a.s.l. from just north of Melbourne, east along the Victorian coast to just before the NSW border. Engaeus quadrimanus has been assessed as Least Concern on the IUCN Red List.

Engaeus quadrimanus - note the burrow entrance behind

Engaeus quadrimanus – note the burrow entrance behind

This specimen is from the west of the range. Collected from the bank of Fish Creek a tributary of the Tarwin River crossing Meeniyan-Promontory Rd, Fish Creek, Victoria.

A very robust and adaptable species that usually has large colonies with the area being riddled with burrows. Typically, burrows are round to oval in shape and open with excavated material at the entrance (see photo). In some areas they can create a pelleted chimney but for many areas it’s just an open hole in the ground as the excavated material has been washed away with flood waters. Burrows are type 2 and relatively basic with only 2-3 surface entrances descending to a horizontal corridor then a deeper burrow to water table. Typically most of the burrow system is flooded and typically they are individual burrows with both males and females having their own burrows. One of the keys to the species is that they are intersexed so hard to determine which are males and which females. Breeding season is autumn and they can be found sharing burrows together then. The species is extremely active during flood events and uses the creeks to migrate and find mates, etc.

Fish Creek

Fish Creek

For a similar article on this species and images from populations further east, go to: http://www.austcray.com/2015/09/engaeus-quadrimanus-from-cann-river-victoria/

Cheers
Rob

 

An expedition to Victoria –November 2015

I had the pleasure of traveling to Victoria to present a lecture on “The Freshwater Crayfish of Victoria” to the Bendigo Field Naturalists Club. They were great crowd and I had a great time chatting with them.

Bendigo Field Naturalist Club

Bendigo Field Naturalist Club

Whilst in the Bendigo area I sampled the local creeks and streams, only finding yabbies Cherax destructor.

Cherax destructor from Bendigo

Cherax destructor from Bendigo Creek

The following day I had an aquaculture consult in the Seymour area and whilst there I took the opportunity to sample the local creeks and streams. Again abundant Cherax destructor but then a very nice surprise. I found a colony of Engaeus lyelli. This was excellent as I also managed to capture berried females, something I haven’t come across in this species before.
For a full article on Engaeus lyelli “Click Here”

Engaeus lyelli

Engaeus lyelli

Travelling south to the Otways the following day I sampled creeks, streams and rivers, finding mostly Cherax destructor and glass shrimp Paratya australiensis. One nice surprise in the Campaspe River were Australian Basket Shell Mussels Corbicula australis. They are a widespread and common species but usually hard to find so finding them easily was a pleasing result.

Australian Basket Shell Mussel

Australian Basket Shell Mussel

Further south around Waurn Ponds another nice surprise was the capture of a berried female Engaeus merosetosus. Enagaeus merosetosus are relatively common and widespread in that area however, females with eggs are exceptionally rare so the capture of one greatly increases the general knowledge on the species. For a full article on Engaeus merosetosus “Click Here”.

Engaeus merosetosus

Engaeus merosetosus

I spent several days at Otway Crays, Bellbrae, Victoria with the owner Steve Chara. Steve is a mate and we spent a few days together surveying the general area. Mostly we were finding Cherax albidus and Geochara gracilis. Both species were abundant and we found thousands. For a full article on Geocharax gracilis “Click Here”.

Geocharax gracilis

Geocharax gracilis

We also found Engaeus sericatus at a number of sites.

Engaeus sericatus

Engaeus sericatus

Steve Chara is one of Victoria’s largest yabby farmers and I spent some time with him sorting, grading and packaging yabbies.

Cherax albidus in a holding net

Cherax albidus in a holding net

Pumkin used to feed Cherax albidus

Pumpkin used to feed Cherax albidus

Steve had a bi-coloured yabby in a tank, this is a rare treat as these are extremely rare animals. For an article on Bi-Coloured Crayfish “Click Here”.

Bi-coloured Cherax albidus

Bi-coloured Cherax albidus

Unfortunately the expedition was over all too soon and I had to head back to the office.

The ACP visits Tasmania

During a recent trip to Tasmania I had the pleasure of seeking some freshwater crayfish between looking at the local tourist attractions. I was there as a tourist for my first look at Tasmania but between traveling to the next tourist attraction I took some time out to look for crayfish and I wasn’t disappointed. Tasmania has an abundance of crayfish species and without too much effort I managed to find a few.

Astacopsis gouldi

Astacopsis gouldi

I was excited to find my first Giant Tasmanian Freshwater Lobster Astacopsis gouldi. Although only juveniles I was very interested in their morphology, I’m looking forward to returning and finding a monster one.

http://www.austcray.com/2015/03/the-giant-tasmanian-freshwater-lobster-astacopsis-gouldi-clark-1936/

Engaeus fossor

Engaeus fossor

The first Engaeus species I found was what seems to be Engaeus fossor. I’m unfamiliar with Tassie crayfish so relying on Horwitz 1990, it keys out as Engaeus fossor, if anyone thinks otherwise please let me know. For an article on this species see: http://www.austcray.com/2015/03/burrowing-crayfish-engaeus-fossor/

Ombrastacoides leptomerus

Ombrastacoides leptomerus

My next find was totally unexpected, I was delighted at finding this Ombrastacoides crayfish in a small swampy drain on the side of a bush track. This was my first Ombrastacoides crayfish and as per Hanson and Richardson 2006 and it seems to be Ombrastacoides leptomerus. I found a number of these in very different habitats. For an article on Ombrastacoides leptomerus see: http://www.austcray.com/2015/03/ombrastacoides-leptomerus/ or http://www.austcray.com/2015/03/ombrastacoides-leptomerus-2nd/

Engaeus mairener

Engaeus mairener

Engaeus mairener is endemic to north-eastern Tasmania, and seemingly abundant being relatively easy to find and with burrows only 60-70 cm deep, relatively easy to dig. For an article on Engaeus mairener see: http://www.austcray.com/2015/03/engaeus-mairener/

Cheers
Rob

 

 

 

 

 

 

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Engaeus sericatus from south western Victoria

 

Engaeus sericatus from the Gellibrand River drainage

Engaeus sericatus from the Gellibrand River drainage

Engaeus sericatus is a small burrowing crayfish from the lowland regions of western and south western Victoria. We found most of our specimens along the edge of the rivers and streams or in small seepages and creeks. As a species it seemed locally abundant at most sites we surveyed, the sites where areas that water seemed permanent and all the burrows had water filled chambers at the bottom. Burrows did not seem to extend far away from the streams into the forest floor and most burrows seemed relatively rudimentary with only 1 or 2 surface entrances down only 500 mm to small water filled chamber.

Small roadside drains/seepages had very high populations of bothe Engaeus sericatus and Geocharax gracilis

Small roadside drains/seepages had very high populations of both Engaeus sericatus and Geocharax gracilis

Engaeus sericatus is found in sympatry with a number of different species. We found Geocharax crayfish within 50 mm and Euastacus bispinosus, Euastacus yarraensis, Cherax albidus and Engaeus fultoni all within 1 metre of the species. Commonly we found that Geocharax crayfish also seemed to prefer the same habitat and at many sites we found them both together at relatively high densities of 2-3/m2 for each species.

Geocharax gracilis from the lower Gellibrand River area found living beside Engaeus sericatus

Geocharax gracilis from the lower Gellibrand River area found living beside Engaeus sericatus