Feral Thoughts

Carp on the move - and into traps!

On yesterday's ABC 666 spot, Dr. Ben Smith of the South Australian Research and Development Institute reported that carp have begun to move in the Murray River, maybe signalling the end of the Australian winter.  Ben is monitoring carp behaviour on Banrock Station in South Australia.  Last year, the Station's wetlands were drained and tens of thousands of European Carp were left stranded - very few carp left the wetlands with the flow of water.  Australian native fish, however, took the opposite decision, leaving with the draining water.

This phenonmenon probably results from different evolutionary responses of native fish compared to carp.  Native fish in a place as dry as Australia probably equate lowering water levels with coming drought and so swim with the flow.  Carp might be associating the water flow with wetlands flooding, which is more in line with their native Asia ("European" carp are actually Asian originally).  Hence, the carp swam against the water flow, into the draining wetland.

Pictured behind Ben in the picture is a carp separation cage.  These cages rely on carp behaviour of jumping over a barrier, whereas Australian natives don't generally jump.  This behaviour is being exploited to separate carp from the rest of the fish population.  Because the Murray-Darling Basin Commission have built fishways from the Hume Dame to the sea, these separation cages are a brilliant development in practical carp control.  The one behind Ben is actually also fitted with a push-trap device to exploit pushing behaviour as well.

Over the past few months, this trap on the inlet to the Banrock wetlands would not contain carp because they are not active at this time of year.  Ben said in the interview that on the drive from Adelaide he noticed Almond trees coming into bloom - a sign of the turning season.  On getting to Banrock he was presented with this haul of carp.

This is another example of the "Achilles' Heel" approach to pest management - exploiting some physical or behavioural feature of the pest to isolate it in some way from the native population.  It's also an example of one of the many, many great things happening on our river system - the lack of water obviously dominates the headlines and we forget that goods things are happening as well.

Flushing an Urban Myth (?)

I think the "Finding Nemo Syndrome" is an urban myth.  This week, Australian media reported that toilet-flushed unwanted pets were the source of feral fish.  Certainly unwanted pet fish are the source of wild populations.  In fact, almost all of about 20 new invasive fish in Australia since the sixties come from the aquarium trade.  There is no question that unwanted fish should not be released into streams, dams or any waterway. 

Nor should live fish used for bait ever be dumped - carp from Wyangala Dam in NSW used for this purpose were probably the source of a carp infestation in Tasmania which closed two Lakes to anglers for a decade and has cost at least $10 million.

However, are there any fish so hardy that they can survive modern wasterwater treatment to establish a feral population?  I strongly doubt it.  I couldn't find any reference to an actual case in the literature (not that researchers are likely to have done experiments to test the hypothesis...). 

The bottom line is don't put unwanted fish into waterways because they could become feral and don't flush live fish down the toilet because its not an acceptable euthanasia method. 

Who or What is a Ratbag?

Returning from a fantastic week on Lord Howe Island, it was a no-brainer to cover rats on last week's radio spot.  A debate is raging on the island about the planned eradication of rats in 2010 and local artist Ginny Retmock had produced some 'ratbags' for the community market.  I bought a few for giveaways but hadn't thought much about the term 'ratbag'.

Presenter Andrea Close asked listeners about the origin of the term, and we decided listener Joyce was probably right in saying it was associated with wanting to keep away from rat catchers who carried a 'rat bag'.  However, a bit of searching since reveals the origin might not be that clear cut.  Most web dictionaries indicate the term as a common Australian one for a larikin; a non-offensive term for someone.  But in use in other parts of the world it seems the term can be for nosey older women or for causing damage ("I got drunk and ratbagged the place").  I couldn't find any historical reference for the term originating from the plague or rat catchers or the like.

Don't let me give the impression Lord Howe is overrun with rats.  They are problem for biodiversity, the kentia palm industry and some locals, but tourists would normally not know they were there.  It's just my particular interest...

Bilbies ain't bilbies

Bilbies have become an iconic image representing many threatened species in Australia.  The long-eared bandicoot used to range over 70% of the country but land clearing, foxes and feral cats have caused a massive reduction in its numbers and range. 

The long ears of the bilby and the devastating impact of the European rabbit on Australia no doubt inspired the idea of the Easter Bilby, now promoted by a number of chocolate companies.  Rabbit Free Australia http://www.rabbitfreeaustralia.org.au/ own the Registered Trademark and image "Easter Bilby" and they have for years received support from South Australia's Haigh's Chocolates www.haighschocolates.com.au/our_company/environment.html

Darrell Lea chocolates also use the bilby image in Easter chocolate sales and in turn provide substantial donations to the Save the Bilby Fund http://www.dlea.com.au/?Community/Partnership/Save_the_Bilby

However, others use the image without providing any known support to threatened species protection or research.  I understand they avoid the Trademark issue by selling their products as Chocolate Bilbies (within their Easter range by not actually "Easter Bilbies") and by simply being too big for a group like Rabbit Free Australia to take on.

So when you buy your Easter Bilbies this year, check the packaging and make sure you support the companies that support threatened species. You'll feel less guilty eating the chocolate that way.

Fijian Cane Toad Song

Cane toads certainly stir the emotions.  Holidaying in Fiji, we were delighted to hear that one of the songs taught at kids club was a Fijian children's tale of cane toads.  The barman explained the words to me as essentially that "cane toads came to Fiji and one has a thousand babies; on his back there is poison, poison, poison".  I'm sure there's more to the song than that and would appreciate a complete translation.

Interestingly, it seemed to be accepted as a fact by indigenous Fijians that the cane toad had been introduced by the Indians indentured to work in the sugar cane industry.  This is a myth.  The indenture system stopped in 1916 whereas cane toads were introduced from the mid 1930s along the same reasoning as in Hawaii and Australia - the wrong interpretation that cane toads controlled white-grub in Puerto Rico after their introduction in 1920. 

Many thanks to the Island Serenders at Treasure Island Resort for singing this version for me.

"That's not a fence: THIS is a fence"

The five kilometre fence in the heart of Sydney erected for security purposes during the APEC Summit is hardly innovative.  The media and public might have adopted the term 'feral fence' for the construction, but 'feral fences' are a long-standing part of the Australian landscape.

The 'dog' or 'dingo' barrier fence that runs from Ceduna in South Australia to outside Surfer's Paradise in Queensland is reasonably well known and the Phil Noyce's 2002 film Rabbit-Proof Fence brought the State Barrier Fence of Western Australia to international attention.  Most people I speak to tend to think of the pest animal fences as things of the past but they remain actively maintained at significant cost and in fact there are proposals afoot for more.  The Western Australian Pastoralist and Grazier's Association has advocated for a $30 million dog fence across outback WA and there is even a small trial of a cane toad fence at Gregory's Tree in the Northern Territory (pictured).

Fences do still play an important role in feral animal management in Australia.  One increasing role is the use of fences on private santuaries to protect species that are vulnerable to feral animal attack.

Join our discussion on the fences that make the so called 'feral fence" at APEC look like a stroll in the park after the 10.00 news on ABC 666 Canberra Mornings with Alex Sloan 5 September.

Cane toad song

We hear more in the news about the western front of toads, now very close to the border of Western Australia.  However, there is a dedicated group of rangers working in Northern NSW to keep the toads at bay on their southern front.  A clever interpretation officer, Kerry Cooper, came up with this song and her kids are the wonderful voices.

The toad call is clearly heard.  The males call to attract the females down to the water's edge.

Does the New England dog project need to include panthers?

We've got a terrific project running in Northern New South Wales, bringing a huge number of players together that have an interest in wild dog control.  I thought it would be an excellent topic for Feral Talkback on ABC 666 but I got distracted when the office temp mentioned she was from the area.  Specifically, she was from Emmaville, a New England town famed for the "Emmaville Panther" - one of Australia's more frequently sighted big cats.

The Emmaville Panther is not alone: there is the mainland thylacine, the Grampians Lion or Puma, the Cordering Cougar, the Queensland Tiger, the Beast of Buderim, the Lithgow Panther, the Tarana Tiger and the Blue Mountains Panther, and probably many more.

Do we simply dismiss these reports out of hand?  In 2001 the NSW DPI investigated the Lithgow Panther sightings because so many were received from credible people and the then Director General, Kevin Sheridan, was reported as being concerned about the Department's duty of care should a human injury occur.  No evidence of a panther was found.  Deakin University is reported to have investigated the Grampian Lion.

The Emmaville Panther was widely reported during 1956-57 and 340 sheep are reported to have been killed on "Pretty Gully", a property near Uralla.  The origin of the panther/lion/puma in this instance and most others tends to be based on escaped circus animals or mascots left by American servicemen.  However, the Sydney Sun (reported via the website www.thylacoleo.com) in 1969 interviewed Arthur Davies who claimed to have trapped a panther in 1939.  Arthur's panther bore remarkable resemblance to the Marsupial Lion, the largest Australian mammalian carnivore, which became extinct in the Pleistocene era, maybe 10,000 to 25,000 years ago, certainly after Aboriginal settlement.

I reckon getting nine Rural Land Protection Boards in Northern NSW working on the Wild Dog Demonstration site represents work aplenty for researchers Peter Fleming and Guy Ballard, without having to worry about panthers/lions/puma/thylacoleo for the moment.  Mind you, any sightings to date unreported would be welcome  on ABC 666 Mornings with Alex Sloan 1 300 681 666 after the news at 10 Wednesday 22 August.

Besides panthers, we'll talk about the wild dog project and remind listeners about the University of Canberra's Open Day this Saturday and the Canberra Indian Myna Action Group's public meeting at Wests Club from 7.30 Wednesday 22 August.