Recently whilst pottering around in the backyard I saw what I first thought was a ringtail possum in the undergrowth. That was until it scampered across the open yard at a pace a ringtail could only dream of attaining on the ground. It was the biggest rat I had ever seen and it seems to have taken up residence in the ponds (i.e. bathtubs and containers I have set-up for fish and frogs) in my yard.
Since then I have seen it regularly and it doesn’t look like the rats I usually see in the urban environment; it was huge at around 1.5 kg and it also had a fluffy tail tipped with white and a slightly golden underbelly. I’ve seen these guys before when fishing so after the first good look at it I knew it was a native water rat (also known as the rakali). That’s where my knowledge on the species ended. Continue reading →
The giant mud crab (Scylla serrata) is a beast of a crustacean, capable of reaching 3kg in weight but often caught around the 0.5-1kg range. In Australia, they are distributed in sheltered waters from southern NSW, up through QLD, across the NT and over to Broome, WA.
Giant mud crabs have a short life cycle (3-4 years) and are reproductive machines. Females can carry between 2 – 5 million eggs and migrate up to 95km offshore to release their eggs. The young crabs hatch as tiny planktonic larvae, where they can remain in this stage for several weeks at the mercy of ocean currents. This aspect of their biology gives giant mud crabs substantial capabilities for dispersal.
A giant mud crab (Scylla serrata) chillin next to some mangroves on Mali Island. Photo by Jürgen Freund. Check out more of his amazing wildlife photos here and on facebook at Jurgen Freund Photography – Australia.
Their prized meat and high numbers within estuaries make them a highly targeted recreationally and commercially harvested species. In NSW, annual commercial landings are approximately 100-120t and the annual recreational catch is estimated between 30-60t. The main method of capture by both commercial and recreational fishers are crab pots, however rec fishers also use hoop nets or dillies.
This guest post is from our mates over at cleancoastcollective. They are on a mission around Australia cleaning up marine debris. The amount of rubbish they are finding in places is crazy, ranging from huge ghost nets to millions of pieces of micro plastics scattered across beaches. Take a read below and check out their crowd funding effort that is under way to fund a rubbish clean up mission to Cape York in the far north of Australia. They are a bee’s whisker away from their $20,000 tipping point and every little extra bit of coin will help them get across the line whilst supporting a really worth while initiative; so consider tipping in some funds if you are able (edit: they reached their tipping point today but getting the whole project fully funded would be great!).
Trashed in Cape York by Clean Coast Collective
We had been told by all of our friends that if we wanted to see serious amounts of marine debris, we needed to venture to the Cape York Peninsula. We were also warned that the experience might be incredibly disheartening.
The journey up to the Cape York Peninsula is quite the expedition – hundreds of kilometres of dirt roads, riddled with corrugations and no mobile reception. Sure, you can go without Facebook for a few hours, but if you break down on these roads, you’d better hope the next person passing you is either a mechanic or a tow truck, because there isn’t a great deal of options if you get stuck. Continue reading →
Receiving a small grant can make or break many honours and post-grads research. I’ve talked to a few honours students lately that needed funding for what I thought was interesting research but without funds their project couldn’t run. With that in mind I thought that I should share a list of grants I’ve had sitting on my hard drive (and that I will add to if I see useful grants down the track) that may help fund small projects. Continue reading →
The Latest UOW Research magazine is out today online —> Here.
There is some marine science action this edition with an interesting article ‘Behind anemone lines’ on the fighting tactics and abilities of sea anemones by Prof David Ayre and I (Lachlan) have got a short write up on my research in the student profile section. Moving off marine science there are interesting stories on climate change, emerging technology, 3D printing & more. Worth a read and its free to boot!
Declining fish stocks and increasing fishing capability worldwide have placed an ever growing emphasis on the need for responsible fishery and species management at appropriate spatial scales. To achieve this, delineating the discrete breeding groups (or populations) of a target species within a given geographical area is of utmost importance. This is particularly challenging in the marine realm, however, where population boundaries are dictated by cryptic barriers to dispersal, a species’ potential for travel and reproductive behavioural traits. Nevertheless, genetic techniques have become an invaluable tool for uncovering population structure in exploited marine creatures.
Demersal longline shark fishing in northern NSW waters as observed during 2008/09. Photo: Dr Geraghty.