Why we don’t know if Irukandji jellyfish are moving south


Kylie Pitt, Griffith University and Dean Jerry, James Cook University

Reports that Irukandji jellyfish might be moving south may be panicking people unnecessarily. It’s almost impossible to tell where the tiny jellyfish are along our coast, but that could change with new technology that can “sweep” the ocean for traces of DNA.




Read more:
Will venomous Irukandji jellyfish reach south-east Queensland?


Since the Christmas period nearly twice the usual number of people have suffered the excruciating consequences of being stung by Irukandji. The stings are rarely fatal, but can require medical evacuation and hospitalisation.

These reports of southward movement are almost a yearly tradition, often sensational, and accompanied by varying expert opinions about whether climate change is driving these dangerous tropical animals south, towards the lucrative beach tourism destinations of southeast Queensland.

But simply counting the number of Irukandji found, or the number of reported stings, tells us very little about where the species can be found.

A simple question but difficult answer

“Where are Irukandji located, and is that changing?”, might seem like a straightforward question. Unfortunately, finding the answer is not easy. The only definitive way to determine where they are is to catch them – but that poses many challenges.

Irukandji are tiny (most are about 1cm in diameter) and transparent. Along beaches they are usually sampled by a person wading through shallow water towing a fine net. This is often done by lifeguards at beaches in northern Queensland to help manage risk.

Irukandji are also attracted to light, so further offshore they can be concentrated by deploying lights over the sides of boats and then scooped up in nets. The problem is they’re are often very sparsely scattered, even in places we know they regularly occur, such as Queensland’s north. As with any rare species, catching them can confirm their presence, but failure to catch them does not guarantee their absence. Collecting Irukandji in an ocean environment is truly like searching for the proverbial needle in a haystack.

Another method is to infer their presence from hospital records and media reports of Irukandji syndrome, the suite of symptoms caused by their sting, but this method has major pitfalls. There is often a delay of around 30 minutes between the initial sting, which is usually mild, and the onset of Irukandji syndrome. Hence the animal that caused the symptoms is almost never caught and we cannot verify the species responsible.

Indeed, we do not know whether Irukandji are the only marine organisms to cause Irukandji syndrome. For example, the Moreton Bay Fire Jelly, a species of jellyfish related to Irukandji only found in southeast Queensland, and even bluebottles, which in the past couple of weeks have stung more than 10,000 people along Australia’s east coast, have also been suggested to occasionally cause Irukandji-like symptoms.

eDNA to save the day

Emerging technology may be the key to properly mapping Irukandji distribution. All animals shed DNA in large quantities into their environment (for example, skin cells and hair by humans). This DNA is called environmental DNA) (or eDNA) and genetic techniques are now so powerful that they can detect even trace amounts.

In the sea, this means we can determine whether an animal has been in an area by collecting water samples and testing them for the presence of the target species’ DNA. This technology is exciting because it provides a major upgrade in our ability to detect rare species. Moreover, it is relatively simple to train people to collect and process water samples, the results can be available within hours, and the equipment needed to analyse the samples is becoming increasingly affordable.




Read more:
The blue bottles are coming, but what exactly are these creatures?


This means an eDNA monitoring program could be easily established in Southeast Queensland to monitor the occurrence and, importantly, changes in the distribution of Irukandji jellyfish. This is because Irukandji leave traces of their genetic code in the water as they swim.

Developing the eDNA technology for use with Irukandji would cost a few hundred thousand dollars – a relatively small price to pay to improve public safety, to provide stakeholders with some control over their ability to detect Irukandji, and to create some certainty around the long-term distribution of these animals.


The authors would like to acknowledge the significant contribution to this article by Professor Mike Kingsford (James Cook University).The Conversation

Kylie Pitt, Professor, Griffith University and Dean Jerry, Associate Professor of Marine Biology and Aquaculture, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Exploring Australia’s ‘other reefs’ south of Tasmania



File 20181217 27779 1tg4cyr.jpg?ixlib=rb 1.1
Solenosmilia coral reef with unidentified solitary yellow corals.
CSIRO

Nic Bax, CSIRO and Alan Williams, CSIRO

Off southern Tasmania, at depths between 700 and 1,500 metres, more than 100 undersea mountains provide rocky pedestals for deep-sea coral reefs.

Unlike shallow tropical corals, deep-sea corals live in a cold environment without sunlight or symbiotic algae. They feed on tiny organisms filtered from passing currents, and protect an assortment of other animals in their intricate structures.

Deep-sea corals are fragile and slow-growing, and vulnerable to human activities such as fishing, mining and climate-related changes in ocean temperatures and acidity.

This week we returned from a month-long research voyage on CSIRO vessel Investigator, part of Australia’s Marine National Facility. We criss-crossed many seamounts in and near the Huon and Tasman Fracture marine parks, which are home to both pristine and previously fished coral reefs. These two parks are part of a larger network of Australian Marine Parks that surround Australia’s coastline and protect our offshore marine environment.

The RV Investigator criss-crossed the Huon and Tasman Fracture marine parks.
CSIRO

The data we collected will answer our two key research questions: what grows where in these environments, and are corals regrowing after more than 20 years of protection?




Read more:
Explainer: the RV Investigator’s role in marine science


Our eyes on the seafloor

Conducting research in rugged, remote deep-sea environments is expensive and technically challenging. It’s been a test of patience and ingenuity for the 40 ecologists, technicians and marine park managers on board, and the crew who provide electronics, computing and mechanical support.

But now, after four weeks of working around-the-clock shifts, we’re back in the port of Hobart. We have completed 147 transects covering more 200 kilometres in length and amassed more than 60,000 stereo images and some 300 hours of video for analysis.

The deep tow camera system weighs 350 kilos and has four cameras, four lights and a control unit encased in high-strength aluminium housings.
CSIRO

A deep-tow camera system designed and built by CSIRO was our eye on the seafloor. This 350 kilogram system has four cameras, four lights and a control unit encased in high-strength aluminium housings.

An operations planner plots “flight-paths” down the seamounts, adding a one-kilometre run up for the vessel skipper to land the camera on each peak. The skipper navigates swell, wind and current to ensure a steady course for each one-hour transect.

An armoured fibre optic tow cable relays high-quality, real-time video back to the ship. This enables the camera “pilot” in the operations room to manoeuvre the camera system using a small joystick, and keep the view in focus, a mere two metres off the seafloor.

This is an often challenging job, as obstacles like large boulders or sheer rock walls loom out of the darkness with little warning. The greatest rapid ascent, a near-vertical cliff 45m in height, resulted in highly elevated blood pressure and one broken camera light!

Reaching into their world

Live imagery from the camera system was compelling. As well as the main reef-building stony coral Solenosmilia variabilis, we saw hundreds of other animals including feathery solitary soft corals, tulip-shaped glass sponges and crinoids. Their colours ranged from delicate creams and pinks to striking purples, bright yellows and golds.

To understand the make-up of coral communities glimpsed by our cameras, we also used a small net to sample the seafloor animals for identification. For several of the museum taxonomists onboard, this was their first contact with coral and mollusc species they had known, and even named, only from preserved specimens.

A deepwater hippolytid shrimp with large hooked claw, which it uses to clean coral and get food.
CSIRO

We found a raft of undescribed species, as expected in such remote environments. In many cases this is likely to be the only time these species are ever collected. We also found animals living among the corals, hinting at their complex interdependencies. This included brittlestars curled around corals, polychaete worms tunnelling inside corals, and corals growing on shells.

We used an oceanographic profiler to sample the chemical properties of the water to 2,000m. Although further analysis is required, our aim here is to see whether long-term climate change is impacting the living conditions at these depths.

A curious feature of one of the southern seamounts is that it hosts the world’s only known aggregation of deep-water eels. We have sampled these eels twice before and were keen to learn more about this rare phenomenon.

Using an electric big-game fishing rig we landed two egg-laden female eels from a depth of 1,100 metres: a possible first for the record books.

Dave Logan of Parks Australia with an eel landed from more than a kilometre under the sea.
Fraser Johnston/CSIRO

In a side-project, a team of observers recorded 42 seabird species and eight whale and dolphin species. They have one more set of data towards completing the first circum-Australia survey of marine birds and mammals.

More coral pedestals than we realise

An important finding was that living S. variabilis reefs extended between the seamounts on raised ridges down to about 1,450m. This means there is more of this important coral matrix in the Huon and Tasman Fracture marine parks than we previously realised.

In areas that were revisited to assess the regrowth of corals after two decades of protection from fishing, we saw no evidence that the coral communities are recovering. But there were signs that some individual species of corals, featherstars and urchins have re-established a foothold.




Read more:
Sludge, snags, and surreal animals: life aboard a voyage to study the abyss


In coming months we will work through a sub-sample of our deep-sea image library to identify the number and type of organisms in certain areas. This will give us a clear, quantitative picture of where and at what depth different species and communities live in these marine parks, and a foundation for predicting their likely occurrence both in Australia and around the world.


The seamount corals survey involved 10 organisations: CSIRO, the National Environmental Science Program Marine Biodiversity Hub, Australian Museum, Museums Victoria, Tasmanian Museum and Art Gallery, NIWA (NZ), three Australian universities and Parks Australia.The Conversation

Nic Bax, Director, NERP Marine Biodiversity Hub, CSIRO and Alan Williams, Researcher, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia: Efforts to Preserve the Southern Brown Bandicoot


The link below is to an article reporting on efforts to conserve the Southern Brown Bandicoot on the NSW South Coast.

For more visit:
http://www.forestrycorporation.com.au/media/releases/helping-the-southern-brown-bandicoot-bounce-back

Australia: NSW – Kiama (2 April 2013)


The photos below were taken at Kiama on the 2nd April 2013, during my NSW South Coast Trip. They include photos of Kiama Blowhole and the Kiama Lighthouse.

Kiama Blowhole

Kiama Blowhole

Kiama Blowhole

Kiama Blowhole

Kiama Lighthouse

Australia: NSW – Sea Cliff Bridge (Grand Pacific Drive – 2 April 2013)


The photos below were taken from Grand Pacific Drive & the Sea Cliff Bridge on the 2nd April 2013, during my NSW South Coast Trip.

View Towards the Sea Cliff Bridge

View Towards the Sea Cliff Bridge

View Towards the Sea Cliff Bridge

Sea Cliff Bridge

Sea Cliff Bridge

Sea Cliff Bridge