A quick survey of some of the mountain streams in collaboration with Blue Mountains City Council proved most enlightening. The local streams draining through suburban areas seemed to have abundant numbers of freshwater crayfish and fish. We were very satisfied with the aquatic health of the streams we surveyed and following is a precis of the main species we encountered in abundance.
Euastacus spinifer is a Giant Spiny Group Crayfish was abundant in the Wentworth Falls area. They are a giant species that grow to a huge size of 1 kg or more and can have spectacular colours. The adults prefer the permanent clear flowing sections of streams and rivers and are active both day and night and can generally be seen wandering the creeks during the day, especially mid-afternoon onwards. In the clear mountain streams if you are quiet and patient you will see them wandering along the creek bed forever in search of tasty morsels.
Also in the same stream were large numbers of native fish. Both the Mountain Galaxias Galaxias olidus and the Australian Smelt Retropinna semoni were abundant in the streams with schools of 100 fish very common.
Euastacus dharawalus is a critically endangered species that is only known to occur in Wildes Meadow Creek above Fitzroy Falls, NSW. There has been some conjecture as to whether or not the species occurs below the Falls. It’s a rugged, inhospitable area below the falls and it had never been surveyed for freshwater crayfish. As part of the Euastacus dharawalus project we conducted the seventh survey in Wildes Meadow Creek and Yarrunga Creek below Fitzroy Falls on the 29th and 30th of May 2012. The first site was on Wildes Meadow Creek at the base of the Falls and then a site on Yarrunga Creek 5.65 km downstream from the falls and the last site a further 4.87 km downstream from site 2.
These three sites were investigated with the surveys being conducted by Robert B McCormack (Australian Aquatic Biological P/L), Justin Stanger (NSW DPI Fisheries) and Prue McGuffie (NSW DPI Fisheries). Each survey consisted of setting 20 traps (10 green opera house and 10 box traps) along a 80-100 m section of stream for a minimum of 120 minutes. Traps were baited with pilchards and set from the bank.
Fitzroy Falls is a popular tourist destination with the Falls dropping 80 m off the escarpment to the creek below where it further cascades over a series of smaller waterfalls and cascades carved deep in the heavily forested lush damp valley. The area below the falls is remote and the only access is from the top of the escarpment. With the assistance of NSW NPWS we managed to find an old disused track to the base of the falls. It was a bit of an effort to get down the escarpment to the base of the falls with our equipment but once there we managed to find some crayfish specimens.
The site was extremely rugged and it was hard to find good fishing spots but Justin carried his waders down the mountain and put them on, hoped into the swift flowing stream and managed to find a number of good locations to set some survey traps. Prue and I watched on with a smile as Justin waded the stream and scrambled over the slippery boulders and jumped, scrambled, fell, slid, bounced and climbed the rapids and waterfalls to get to the very base of the Falls.
We were unable to find any Euastacus dharawalus below the Falls, only finding Euastacus yanga and Cox’s gudgeons. Interestingly the Euastacus yanga we were finding were an unusual morphological variety without much in the way of abdominal spines, but extra spines on their claws.
It was an interesting survey that concluded E. dharawalus does not occur below the falls and I’m grateful to NSW DPI Fisheries for all their help and assistance.
This is a relatively small dwarf group crayfish that is shy and elusive, with an extensive burrow system. We were researching streams draining the Dorrigo plateau south of Dorrigo. The streams were clear and fast flowing and Euastacus neohirsutus was plentiful in the area. They tended to be in the upper catchments with Euastacus dangadi in the lower regions.
They are a common species around the Nymboida, Dorrigo and Coffs Harbour areas. Occurring in the catchments of the Nambucca, Bellingen and Macleay rivers (Styx River) and Clarence River (Little Nymboida, Nymboida, Orara and Bobo river systems). Though common they are rarely seen spending most of their time in flooded burrow systems. We surveyed tributaries of the Rosewood and Never Never Rivers which are all tributaries of the Bellinger River. We found them in every stream we surveyed and they seemed abundant in the area.
Australian Aquatic Biological P/L Report 100056-8 to Gosford City Council included a survey of Green Point Creek at Pearl Beach, NSW. The creek was surveyed at the crossing on Diamond Road.
Here the creek here was strongly flowing over a sandy stream bed. There were shallow areas and deeper holes. The banks had some rock retaining walls but were well shaded with ferns and palms, etc. The creek was extremely healthy with abundant aquatic species present. Some plague minnows Gambusia holbrooki were present, we observed a small long finned eel, several flat headed gudgeons, many striped gudgeons and common jollytails.
Further upstream at Tourmaline Avenue the creek was surveyed again, here the stream was again sandy based with deeper holes and looked in excellent condition. We surveyed the stream finding only dozens of striped gudgeons and surprisingly the White Cloud Mountain minnow Tanichthys albonubes. The White Cloud Mountain minnow is an exotic freshwater fish. It is a species that would normally be found in a fish tank so it is alarming that this exotic species is established in numbers within this stream. It is a robust species and a member of the carp family being a native of China. Their robust nature and bright colouration makes them popular as an aquarium species and they are not normally found in natural waterways of NSW.
I did some research on this species and found that, NSW DPI has known about this feral population since late 2002 and continues to monitor the situation. Unfortunately, one of the specimens collected was gravid so conditions were suitable for breeding which is a big worry. Discussions with residents in the area report Australian Bass and eels in the deeper holes and freshwater crayfish further upstream.
Discussions with the Australian Museum also record this species from Piles Creek at Somersby, NSW. We did a preliminary survey of this creek specifically targeting the White Cloud Mountain Minnow but were unable to find it. That does not mean it’s not there however, it does indicate that it’s not proliferating well and numbers are either very small or scattered, etc. Unfortunately, we did find invasive Cherax destructor proliferating in the stream so that was not so good news.