The Possum

There's a rustle in the Mulberry Tree
And the dogs go bark bark bark
Whatever could it be
On this night so still and dark

There’s something in the Pepper Tree
In a hollow deep and dark
Hiding where we cannot see
As the dogs go bark bark bark

We need to solve this mystery
Of what's hiding in the dark
Lying still as still can be
As the dogs go bark bark bark

One of the reasons we bought our house was the Brush-tailed Possum in a hollow in the Pepper Tree outside the house yard. The hollow is about 1.5 metres above ground level and looking out was a whiskery face with huge eyes and a pink nose. He was very cute. And we know he is a he because we got a nice shot of his rear end with the sensor camera we set up near the hollow. Our dogs are confined to the house yard so the possum can safely roam the grove of trees in the two acre property outside the house yard. He is very fond of the wild quandongs and we sometimes hear him in the mulberry tree next to the house yard, where he initially used to drive the dogs crazy but they got used to him soon enough. Sometimes though he likes to live dangerously. Like the time we found him on the kitchen bench one night and this time the dogs on sentinel duty on the front veranda were oblivious.

Not everyone likes possums and particularly people in New Zealand where Brush-Tailed Possums are an introduced pest and where interestingly they are rapidly growing into a much larger animal than their Australian cousins. That's the irony of pest species that are actively hunted. The fit survive and in a very short time the species becomes formidable. The same thing is happening with the North American Coyote and of course Australia's feral fox. Brush-tailed possums, like kangaroos, are a species that have done quite well out of the European Settlement of Australia. Dozens of mammals have become extinct but the hordes of possums in the trees and roof cavities of Brisbane, Sydney, Adelaide, Melbourne and Perth are doing very well and drive people mad with their midnight carousing. So far we have been lucky and have not had a possum invasion in our roof space or our chimneys but it will likely happen one day. In the meantime I am very happy to coexist with our cute neighbour in his Pepper Tree hollow.      


 

The Cuttlefish Aggregation

The bride is truly stunning
As she hovers into view
With her wedding dress all pulsing
Bright electric blue

Rippling and shimmering
In ever changing hue
Sometimes brown and cryptic
Sometimes brilliant blue

The cuttlefish keep coming
To join the congregation
And the mating dance has started
In the swarming aggregation

For year after endless year countless thousands of cuttlefish would arrive on the rocky sub-tidal terraces off Point Lowly near Whyalla to breed and lay their eggs. It was one of the world's great swarming aggregations and a marvel of nature. It was also a marvel for the fishermen who plundered them by the tonne until the population collapsed, or almost so, before they were protected in the Point Lowly Zone in 1998. The population at first recovered but unaccountably again began to decline over past few years. This prompted an extension of the protected zone to the whole of the Northern Spencer Gulf in 2013. The reasons for the decline are not understood but a recovery of sorts does look like it is happening.  I was delighted to see them in their hundreds, if not the thousands of legend, when I visited Point Lowly in late May 2014. The rocky terraces between Point Lowly and Black Point are marvellous for a seaside picnic and continue to cascade into the clear sheltered water. I saw my first cuttlefish nestling in the sea-weed in about 2 metres of water about 20 m off-shore and then saw more and more as I ventured further off-shore. They can reach 0.5m in length and weigh up to 10 kg so they are a very impressive animal but most of the ones I saw were much smaller than that. And so pretty! I had the tune of Ice-house's Electric Blue running through my head as I watched one of these pulsating marvels of nature flashing brilliant blue. You can swim right up to them and they barely move. I came face to face with one who was a dead ringer for Ood from Dr. Who.  Let us all hope that the recovery continues and that these priceless marvels of nature one day return in the hundreds of thousands of yester-year.  And in the meantime let's enjoy the ones we still have.  If you are ever in South Australia in  May and June you should make the effort to swim with the cuttlefish.  

Razor Fish

The Razor Fish are far and few
Where once so thick and close
How can they all have gone so fast
Along the Spencer coast

Once they were just used for bait
But now the high demand
To have them on a gourmet's plate
Is causing quite some harm

They are tasty sure enough
But it hardly seems worthwhile
To kill them for the tiny snack
Within their giant shell

The Razor Fish, or Razor Clam as they are known outside of South Australia, is  a large fan shaped shellfish found with the pointy end buried in the mud and the top few centimetres exposed. Just enough to inflict significant damage on the bare foot of the unwary! They once carpeted the seagrass beds that cloaked the calm shallow inlets near Adelaide but they are now quite rare near any population centre. You need to travel further afield to places like the Upper Spencer Gulf  to see them in any numbers and even there the populations are plummeting. The bag limit is 25 per day but the day will soon come when this will have to be lowered. They are obviously being over-fished.

The loss of the Razor Fish is a tragedy in its own right even if it does mean less cut feet but they are also very important in the ecosystem. As well as being efficient filter feeders that clean up the water they are also a hard surface for epiphytic algae and for a range of animals. If you look hard in the photo you will see an abalone attached to one of the shells. So the loss of Razor Fish is also the loss of a suite of other organisms that all have their place in the ecosystem.

The other tragedy is that they are really not worth the effort as a sea-food. They are trendy for sure and the rarer they get the more status they hold. A bit like a bears gall bladder in China! But the small white adductor muscle, which is the only edible part, is such a small part of the large animal and you still need to get rid of the waste. The reality is that the 25 Razor Clams you have spent the day collecting on the mudflats will barely provide a decent meal for one person and will fill the rubbish bin with smelly waste. The flavour is also very strong. I think scallops are a much better bet and consuming those is much better for the environment.











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Great White Sharks

White Shark attacks keep increasing
And calls for a cull are unceasing
Despite greater surveillance and policing
And stocks of White Sharks decreasing

These calls for a cull are delusion
And improved shark safety illusion
It’s a media driven conclusion
That is creating public confusion

Understanding our shark interaction
Is key before we take action
And avoids a mindless reaction
That will not get shark safety traction

The recent decision by the WA Barnett Government to allow the culling of White Sharks is appalling. It is political expediency at its worst. There is absolutely no doubt that it was a decision taken against the advice of his own scientific departments. It’s about public appeasement and being seen to be doing something about the unprecedented number of fatal shark attacks in Western Australia in the past couple of years. And while the premise that human life must take precedence over that of a shark will strike a chord with a large proportion of the voting public it will do little if nothing to reduce the risk of a shark attack. Great White Shark attacks invariably occur on solitary surfers and divers and not on crowded Perth beaches. Culling White Sharks will not change this and at worst will give people a false sense of security. The key point is that White Sharks are a vulnerable protected migratory species. They are also an apex predator critical to the health of the marine ecosystem. If Australia ignores its commitments under the numerous international treaties designed to protect endangered species then it will have no credibility in international forums. Our call on Japan to stop whaling in the Antarctic Whale Sanctuary for example will smack of hypocrisy. Australia is a world eco-power with control over large areas of the world’s oceans. We should be a leader in marine research and conservation but we are quickly sliding down the scale. The current trend of slashing funding to science and research and ignoring scientific advice at both federal and state level is deeply disturbing. If the Barnett Government was truly committed to reducing the risk of shark attacks it would be funding research programmes to understand why it is that shark attacks are increasing at the same time that the population of Great White Sharks is falling. Understanding this will help us understand what we must do to reduce the risk of a shark attack. We must also keep things in context. The risk of a shark attack is miniscule to that of drowning and of course to being killed on the road. The analogy with road fatalities is very apt. No one suggests that culling cars will improve road safety. It is all about driver behaviour and understanding the risks. There are interestingly more road fatalities in country areas with less cars. It is exactly the same with sharks.

Abalone Dreaming

 

 

 

 

 

 

 

 

 

 

 

 

Coastal life is the life for me

With beach and surf and clear blue sea

Where I can fish with my family

And dive the reef for abalone

 

Our lovely city by the sea

Has so far kept its harmony

With a well managing fishery

And foraging still largely free

 

The Ocean Reef Marina

Needs a second thought

With a million abalone

Soon all gone for nought

 

 It’s almost a truism that every development will be opposed by a special interest group.  But ultimately effective consultation, good-will and a capacity to compromise will secure a balanced outcome that serves the common good.  The important thing is that the process is open and transparent and that the decision makers are well informed.  Where things become murky is when key information is deliberately withheld in order to secure a favourable outcome for the proponent. The word for this is “spin” and a classic example is the proposed ocean reef marina that is being heavily promoted by the Joondalup City Council. The information presented on the council website is impressive (http://www.joondalup.wa.gov.au/develop/majorprojects/oceanreefmarina.aspx ). Impacts on the feeding grounds of the endangered Carnaby’s White-Tailed Black Cockatoo and the endangered Graceful Sun Moth have been well studied and community consultation has been extensive.  There is apparently overwhelming community support for the Project.  The key question though is why impacts on abalone are not mentioned.  The proposed Ocean Reef Marina will take out about 10 ha of the best abalone habitat in the Perth coastal zone. There is literally a carpet of abalone on the offshore reef that will be removed to make way for the marina. The abalone fishery is well managed and Fisheries Officers are quick to hammer anyone who takes more than their 20 daily bag limit or any undersize animals during their five by one hour allowed fishing sessions each year.  How can this be reconciled with the loss of possibly one million abalone from the recreational fishery?  Imagine the outrage towards an individual who harvested 50 tonnes of abalone out of a tightly controlled fishery and then consider that not only is the council proposing to do exactly that but to also permanently remove the habitat.  There is no shortage of sandy habitat to build a marina. It is simply not necessary to destroy precious rocky reef in the Marmion Marine Park to build the marina. It beggars belief that the Council is unaware that the marina will take out a large area of prime abalone habitat.  Their strategy of not mentioning it as an issue smacks of deliberate misrepresentation. It has to be tabled as a key concern. In the words of Virgil Kane: “You take what you need and leave the rest but they should never have taken the very best”.

Evolutionary Harmony

 

 

 

 

 

 

 

Species evolution

Through survival of the fit

Was first proposed by Darwin

But such thoughts have changed a bit   

Individual adaptation

Is just one part of it

There is also exaptation

And inter-species fit  

Genetics is quite complex

With genes the building blocks

That may dominate or recess

And at times switch on and off

Darwin’s “On the origin of species by means of natural selection” is a remarkable work made even more so by its publication before the discovery of genetics.  Whilst the basic theory has stood the test of time it should be viewed as a foundation work for evolutionary studies and not as a “holy book” for evolutionary biologists.  Its main potential issue is that it presents a depressingly bleak view of a dog eat dog world similar to Tennyson's “nature red in tooth and claw”.  The deeply compassionate and gentle Darwin would have been horrified to see his theory used to justify the extremist views of white supremacists including the Nazi’s. The strong shall prevail!  In practice “survival of the fittest” means much more than being the best competitor. Species can and do support each other and whilst every species must eat there is also great harmony and interdependence in the web of life.  The struggle to survive is always there but the day to day lives of most species are happy and contented. At its extreme you end up with an interdependent living planet or Gaia as presented so brilliantly by Tim Flannery in his book , “Country”.

I like the concept of exaptation where a particular advantageous trait becomes a foundation for further adaptations such as birds first developing feathers to keep them warm and then finding they are useful for flight. This solves many directional evolution puzzles.

Perhaps the most fascinating concept of all is that of co-evolution.  There are many examples of birds and insect pollinators co-adapted with specific flowers but it can be more subtle that. My all time favourite book is David Paxton's “Why it’s OK to talk to your dog”. It presents a compelling case on the co-evolution of dogs and people which ultimately gave humans the edge over our Neandertal competitors. Modern man in partnership with the dog could afford to forgo an acute sense of smell and hearing in return for greater thought and speech capacity.

The Kraken Wakes

  Photo is a diver dwarfed by a giant jellyfish.
Credit: Yomiuri Shimbun from:
 http://www.livescience.com/13112-giant-jellyfish-blooms-ria.html

Before the Age of Fishes
The acid seas were warm
And filled with slimy jellies
In an endless pulsing swarm

But much carbon was sequestered
And the seas began to cool
And teams of bony fishes
Began to swim and school

Our seas are turning acid
And becoming very warm
And the ancient slimy monsters
Once more begin to swarm

I recently saw a frightening programme on Giant Jellyfish infestations in the Sea of Japan. Billions of giant Nomura Jellyfish weighing up to 200kg are choking the Sea of Japan and have destroyed the fishing industry. Similar events are occurring in the Gulf of Mexico, China's Yellow Sea and in the Black Sea. Overfishing, pollution from fertilisers and global warming have all been implicated but there is no doubt that the ancient jelly-fish which dominated the worlds oceans 300 million years ago are much better at coping with warm, acidic and low oxygen conditions than modern fish. Fisheries are collapsing everywhere and wild ocean fish stocks are now perhaps 10% of what they once were. We are in the process of turning back the clock 300 million years and unless we change our ways quickly we will be truly damned. Scientists are struggling to understand this latest catastrophe but my time as a salt field ecologist has given me an inkling as to what may be going on. I suspect that the balance between benthic and planktonic ecosystems has been disrupted as a consequence of pollution from fertilisers, pH drop from increased dissolution of CO2 and, general ocean warming. Weed-eating fish in the early ponds of a salt-field graze the seaweeds and deposit nutrient in waste onto the floor of the ponds where it is bound up in the mud. The continually grazed seaweeds regrow taking nutrient out of the water column and helping to secure clear water with big populations of fish and carpets of sea-weed. When a catastrophe killed the fish, excess nutrient ended up in the water column where it promoted blooms of phytoplankton and the once clear and fish filled water became a fish-less, soupy mess similar to what has happened in the sea of Japan.