As a general rule, the different species of crayfish have developed individually
due to four distinct factors. These are geographic barriers, water
availability, temperature and predators. There has been, over the years,
a lot of concern about introducing species of crayfish from one area and those
crayfish escaping into the wild and taking over from the native species.
Though this is always a concern, however, unless all the four criteria are met,
then a non-indigenous species will not survive. Most Australian species have very small distributions but some have large distributions because they can withstand wide variations of these factors. These species are the ones with the potential for translocation and impacts on the native species in that area. The majority of Native
Australian species have very specific environmental requirements and will not
survive outside those narrow limits. This is an extremely worrying fact
that will have dire consequences for many Australian species of crayfish as we
enter a period of continental-wide climate change. A few of the Australian
species, like the yabby Cherax destructor, have extremely wide environmental
tolerance limits and this makes them very dangerous as they can survive just
about anywhere on the planet.
All these species can be very similar
in appearance to other related species. All the species have different colour
variations and many have morphological differences between populations.
Add that there are differences in appearance between juveniles and adults and
that all adds up to one enormous identification difficulty. The culmination of the Australian Crayfish Project will be full colour Field Guides to all the freshwater crayfish of Australia. Initially for each State/Territory of Australia 2 guides will be generated.
Firstly, a smaller general public book for that state and then a larger in depth Field Guide to the Crayfish of the state. Finally after all the individual states are done The Field
Guide to the Freshwater Crayfish of Australia will be compiled. These books will help alleviate identification problems and raise the knowledge base on freshwater crayfish in Australia..
There
is a desperate need for a guide of this type, many people
catch freshwater crayfish as pets yet are unable to identify the species they have
captured so are unable to look after them in the required manner and they eventually
kill them. Additionally, with the trade in Native species increasing
worldwide, there is a desperate need for a ready guide to identify species
for Fisheries and Customs personnel. This survey is also identifying
previously unidentified and undescribed species – this in itself is an
essential task. Many of the unidentified species are endangered and will
not be considered in developments as they are unrecognized as endangered species. By identifying them and notifying the authorities of their existence
may help ensure their continued existence.
The Australian Crayfish Project is
a long term project that was started in early 2005 and is not due for completion
till late 2017 (or later) when the Field Guide to The Freshwater Crayfish of Australia
will be completed. Stage I is a Field Guide to the Freshwater Crayfish
of NSW. The first book "The Freshwater Crayfish of NSW, Australia" is available for purchase. The Freshwater Crayfish of Qld & Vic are in preparation, but the discovery of new species is delaying the guides.. A guide to Australia's Spiny Freshwater Crayfish was released in 2012. To purchase click here.
Additionally,
any information you may have on unusual crayfish species in your area would also
be appreciated. This project is being helped by researchers, university
staff, National Parks Officers, aquaculture association members, crayfish enthusiasts
and the general public. Over the last 20 years plus as a crayfish
farmer, TAFE lecturer, President of the Aquaculture Association, and author
of various crayfish books, I have had the privilege of meeting and talking
to a vast number of crayfish researchers and fellow enthusiasts from around the
world. Over the years I have taken in every hint and comment about
weird or unusual crayfish from around Australia and recorded them in a journal. Now, with 25 years of information on locations and species to check out,
I am slowly checking them all.
So far by mid 2013 we have described three new species, and have five others due for publication plus two redescriptions of known already described species. We currently have another eighteen suspected to be new species that we will describe over the next few years. We have only just started, who knows how many
others are out there and what will be discovered over the next two, three or more years. If you have something unusual in your area let me know and let's get together
and check it out.
For full details on the Australian Crayfish Project go to www.aabio.com.au
Rob McCormack
