Tag Archives: Australia

Dottyback reef fish is a “wolf in sheep’s clothing”

A new study by researchers at the University of Cambridge has shown that the dottyback, a small predatory reef fish, can change the colour of its body to imitate a variety of other reef fish species, allowing the dottyback to sneak up undetected and eat their young. Its Latin name, Pseudochromis, means false damselfish – giving clue to its mimicry abilities.

The dottyback also uses its colour-changing abilities to hide from larger predators by colour-matching to the background of its habitat – disappearing into the scenery with its camouflage.

While using mimicry to hunt or hide from other species is commonplace in nature – from cuckoos to cuttlefish – scientists point out that if the same physical deception is encountered too frequently, species on the receiving end become more vigilant and develop tactics to mitigate the mimics.

The dottyback, however, is able to colour-morph depending on the particular colour of the surrounding species it is currently hunting: different types of damselfish being a popular target.

Scientists say that this flexibility of physical mimicry makes it much harder for the dottyback’s prey to develop detection strategies and avoid getting eaten.

Dottybacks are generally solitary and highly territorial predators of around eight centimetres in length, commonly found in Indo-Pacific coral reefs.

While dottybacks can vary their colouration from pink to grey, the researchers focused on two colour ‘morphs’ – yellow and brown – that both occur on the reefs surrounding Lizard Island, off the coast of north-east Australia. This is because the area has populations of both yellow and brown damselfish, and habitat consisting of live coral and dead coral ‘rubble’.

Dottyback and damselfish

The scientists built their own simulated reef outcrops comprising both live coral and rubble, and stocked them with either yellow or brown damselfish. When released into reefs with damselfish of the opposite colour, scientists found the dottybacks (Pseudochromis fuscus) would change from yellow to brown or vice versa over around two weeks.

Anatomical study of dottyback skin cells revealed that while the level of ‘chromatophores’ – pigment-containing cells that reflect light – remain constant, the ratio of yellow pigment cells to black pigment cells shifts to move the dottyback from yellow to brown or back again.

The team conducted lab experiments with adult and juvenile damselfish to test whether this colour change affects dottyback hunting success. They found that once the dottyback matched the colour of the damselfish, they were up to three times more successful at capturing juvenile damselfish.

“This is the first time that an animal has been found to be able to morph between different guises in order to deceive different species, making the dottyback a pretty crafty little fish” says Dr William Feeney, co-author of the study from the University of Cambridge’s Department of Zoology.

Further Reading
University of Cambridge (CC BY-NC-SA 3.0)

Photo credits: Christopher E Mirbach, Justin Marshall.

Great Barrier Reef: Australia to ban Sediment Dumping on Part of Reef

Australia has declared that it will ban dumping of sediment in the marine park area of the Great Barrier Reef, but not in the entire World Heritage Site. This matters because, according to environmental pressure group Fight for the Reef, in recent years 80% of dumping has been in World Heritage waters just outside the Marine Park.

During a speech in Sydney at the World Parks Congress, Environment Minister Greg Hunt said that the government will legislate a ban on dumping.

Spoil will still affect Coral and Seagrass

A ban in just the Marine Park, though, would still allow millions of tonnes of spoil to be dumped where plumes can easily drift onto coral and seagrass.

The expansion of Abbot Point, to make it one of the world’s biggest coal ports in middle of the Great Barrier Reef is still going to go ahead – this time with the dumping of toxic sludge on wetlands. Wetlands are the filters and the fish nurseries for the Reef.

Groups press to protect entire World Heritage Area

Environmental groups are pressing for the government to protect the entire World Heritage area or risk an ‘in-danger’ listing for the Reef from the World Heritage Committee.

Practically the entire Great Barrier Reef was inscribed as a World Heritage site in 1981. It contains the world’s largest collection of coral reefs, with 400 types of coral, 1,500 species of fish and 4,000 types of mollusc. It also contains habitats of species like the dugong and the large green turtle, which are threatened with extinction.

Green Turtle
Green Turtle, Chelonia mydas

In June 2015 the World Heritage Committee will decide whether to place the Barrier Reef on the List of World Heritage in Danger.

Fight for the Reef is a partnership between WWF-Australia and the Australian Marine Conservation Society.

Further Reading
Fight for the Reef
World Heritage List: Great Barrier Reef

Little Support for Shark Culling

Following another fatal shark attack in Australia, new research finds little support for the shark cull.

A survey of 583 aquarium visitors asked people how they thought the Government should respond to shark bites and found that despite the public’s fears, 87 per cent favoured non-lethal responses.

Only four per cent of those surveyed supported the hunting of sharks.

Another key finding was that only 2-4 percent blamed the Government and only slightly more (6-8 percent) blamed the sharks. Most responsible were thought to be either the swimmer or simply no-one.

Conducted by University of Sydney Lecturer Dr Christopher Neff and funded by the SEA LIFE Conservation Fund, the survey is the first research of its kind. Dr Neff stated, “These responses show that there is little support for government measures that kill sharks and that the public does not blame governments when these tragedies occur.”

“The Australian public is ready for some new options” said Claudette Rechtorik, Director of the SEA LIFE Conservation Fund. She added, “The findings from this data are consistent with what we hear every day. After 77 years of shark culling in New South Wales it is time to consider something else. We…believe the research is important for policymakers to consider given that it suggests that the Government should respond to shark bites with greater public education and non-lethal shark culling measures.”

The research comes as Western Australia seeks to extend its shark cull policy by three years.

Based on state figures released in March, the WA shark cull policy has killed 41 sharks of which 95% were tiger sharks. The sharks ranged in size from 1.7 m (a Mako) to 4.1 m. Ten were already dead: killed by the drum lines. The rest were destroyed. The government has not released any information on the numbers of other animals killed by the drum lines.

Photo credit: Albert Kok

42,000 Turtles legally killed each year

Over 42,000 turtles are legally killed each year, 80% of them endangered green turtles (Chelonia mydas), a study suggests.

British scientists investigated which countries allowed turtles to be killed, and how many of each species died, the Diversity and Distributions Journal reported.

Ten countries account for more than 90% of the catch, with Papua New Guinea, Nicaragua and Australia taking almost three-quarters between them. Legal take of turtles is comparable to estimates of by-catch.

Widespread commercial catch of turtles has contributed significantly to their decline.

The first place to protect turtles was Bermuda, as early as 1620. Although 42,000 seems an enormous number now, in the 60s Mexico alone was catching over 380,000 a year. The IUCN Red List of threatened species has listed marine turtles since 1982, giving them protection from the 198 countries now signed up to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

The IUCN writes that “Perhaps the most detrimental human threats to green turtles are the intentional harvests of eggs and adults from nesting beaches and juveniles and adults from foraging grounds.“. Other threats include bycatch in marine fisheries, habitat degradation at nesting beaches and feeding areas, and disease.

As well as 37,339 green turtles, an estimated 3456 hawksbill turtles, 1051 loggerhead turtles, 263 olive ridley and 62 leatherback turtles are captured.

Further Reading:
Humber, F., Godley, B. J., Broderick, A. C. (2014), So excellent a fishe: a global overview of legal marine turtle fisheries. Diversity and Distributions. doi: 10.1111/ddi.12183

Sea Simulator to Solve Seas’ Mysteries

Australia today opened the National Sea Simulator to tackle ocean issues. This research aquarium is aiming to discover:

  • How well will the Great Barrier Reef adapt to a changing climate and more acidic oceans?

  • Why do crown-of-thorns starfish populations periodically boom?
  • Can we develop technologies to control crown-of thorns and give the Reef time to adapt to a changing climate?
  • Is coral bleaching simply a reaction to hot oceans or is something more complex happening?
  • Whether bacteria and viruses will become dominant as climate change takes hold?

The $35 million SeaSim gets closer to replicating the conditions of the open ocean, a reef lagoon or flooding rivers than any other facility in the world.

“It’s awesome,” says Australian Institute of Marine Science (AIMS) researcher Mike Hall. “When we started planning SeaSim we visited over 40 marine aquariums around the world to identify key attributes of the perfect research facility. What we’ve built takes the best in the world and adds new technologies and an incredible level of automation and control.”

“In each tank we can automatically control many parameters – from water temperature to ocean acidification to salinity to lighting to nutrients and water quality etc.”

“SeaSim will allow marine scientists the world over to test observations, assumptions and models. It will allow the development of technologies to assist aquaculture and fisheries management.”

“Fighting the crown-of-thorns starfish is one of the highest priorities for SeaSim,” says John Gunn, the AIMS CEO. “We need to understand why starfish populations periodically boom leading to massive reef destruction. Is it due to nutrients in flood waters or are more complex factors at play?”

“Crown-of-thorns talk to each other with chemicals – they gather in groups and they ‘run away’ when predators such as the Giant Triton move in to feed on them. Could we use those chemical signals to trick starfish into congregating or dispersing – making physical removal easier? We hope to answer these and many other questions about the starfish with the help of SeaSim,”

SeaSim brings together a reliable, consistent supply of high quality seawater with the technology to enable precise control over environmental factors like temperature, light, acidity, salinity, sedimentation and contaminants. It integrates technology developed in the industrial process sector—-used to control and manipulate seawater and ambient conditions—-with aquarium technologies of plant and animal husbandry.

The Sea Simulator was opened by Senator Kim Carr who said the Government had funded the SeaSim because it was essential for Australia to better understand the impact of events such as ocean warming and acidification, outbreaks of natural predators such as the Crown-of-Thorns Starfish and pollution.

Further Reading:
About SeaSim, the National Sea Simulator

Australians urged to petition for National Plastic Bottle Deposit Scheme

Every year 7 billion drinks containers are littered or landfilled in Australia. Campaign group “Kicking the Can” are asking Australians to sign a petition urging the government to set up a national container deposit system. They say that “Introducing container deposit legislation [CDL] (a 10 cent refund like they’ve had in South Australia since 1977) is the most important step Australia can take to restrict plastic pollution entering our oceans, killing wildlife and poisoning the marine environment that we all rely on.”

Plastic is made to last, so it decays only very slowly in the oceans, breaking down into ever smaller fragments. These tiny fragments are known as micro-plastic. Micro-plastics attract toxins onto their surfaces, and are eaten by plankton who mistake them for fish eggs. From plankton they pass up the food chain and back to us.

Filter feeders like mussels accumulate the plastic as they filter the water. This concentrates the plastic and effectively turns some of those molluscs into hermaphrodites. The very small plastic particles can mimic certain things like oestrogen.

Kicking the Can predict that a National container deposit scheme will solve the massive problem of beverage container litter, drastically increase recycling, provide jobs, cut costs to Council waste collection and provide fundraising opportunities for schools and community groups.

Australians can send a letter to a state minister imploring the Australian government to implement a National Container Deposit System at http://kickingthecan.org.au/take-action/.

Further Reading
Kicking the Can for Australia
What are long term threats of plastic in our seas?, BBC

Australia Creates World’s Largest Marine Park

Australia today announced the creation of the world’s largest marine reserve, covering the Great Barrier Reef and the Coral Sea. Oil and gas exploration will banned but commercial fishing will be allowed in many areas.

Australia’s marine reserves will increase from 27 to 60, covering one third of the nation’s seas.

The announcement of the reserves was made a week before more than 130 countries congregate for the United Nations’ sustainable development conference in an attempt to limit climate change, one of the biggest conferences in U.N. history.

Environmental groups welcomed the news, with WWF-Australian CEO Dermot O’Gorman saying “Australia has the third largest ocean territory in the world that stretches from the tropics to the sub-Antarctic and is home to incredible creatures such as whales, dolphins, turtles and sharks as well as spectacular corals and other ecosystems”. However they called for places like Rowley Shoals and Ningaloo Reef off Western Australia to also be protected.

IFAW (Interational Fund for Animal Welfare) commented “The IFAW is pleased to see important parts of the humpback whale nursery in the Kimberley and some southern right whale calving grounds off the south west coast included in the network, but critically important feeding grounds for blue whales…remain insufficiently protected. While northern parts of the Perth Canyons have been protected from oil and gas exploration, the remainder is still open to exploration and the damaging effects that can have on whales. This means that to some extent all three of the recognised blue whale feeding grounds in Australian waters are still open to negative impact from offshore petroleum exploration and production. The Environment Department has had its hands tied throughout the whole process in any attempts to address the threats to marine life from the oil and gas industry. The network, for the most part, addresses areas only where the industry doesn’t operate or isn’t looking to operate in the future.”

Australia Environment Minister, Tony Burke, said “We have an incredible opportunity to turn the tide on protection of the oceans and Australia can lead the world in marine protection”.

Two weeks ago a U.N. report said the Great Barrier Reef was under imminent threat from industrial development and may be considered for listing as a world heritage site “in danger” in February next year.

Related News:
Will Marine Reserve Protect Coral Sea Sharks?

Diving the Marine World Heritage Sites

Forty-five World Heritage Sites – places of “outstanding cultural or natural value” – are located in marine areas. And many are also fabulous diving spots. Jointly, marine World Heritage sites comprise one third of the planet’s marine protected areas, in 34 countries. They are designated by UNESCO, the United Nations Educational, Scientific and Cultural Organization.

The first marine Heritage Site to be listed was the Galapagos Islands, in 1978. In the Pacific Ocean some 1,000 km from the South American continent, these 19 islands and the surrounding marine reserve have been called a unique living museum and showcase of evolution. Situated at the confluence of three ocean currents, the Galapagos are a melting pot of marine species.

Next listing was Australia’s Great Barrier Reef. It contains the world’s largest collection of coral reefs, with 400 types of coral, 1500 species of fish and 4000 types of mollusc.

Dugong or Sea Cow

Australia has the most Marine World Heritage sites of any country: five. Ningaloo Coast was inscribed most recently in June 2011. Ningaloo, in Western Australia, is famous for its whale sharks. Also on the West coast is Shark Bay. This has three exceptional natural features: its vast sea-grass beds, which are the largest and richest in the world; its dugong (sea cow) population; and its stromatolites. Stromatolites are rock like structures built by microbes, similarly to how corals build reefs. Shark’s Bay stromatolites are 2000 to 3000 years old, but stromatolites have been being built for 3.5 billion years. Shark Bay is also home to five species of endangered mammals.

Further north is the Philippines’ Tubbataha Reefs Natural Park. In the middle of the Sulu Sea, Tubbataha is 128 km from inhabited islands and is dived by liveaboard from March to June. The site comprises pristine coral reef with perpendicular walls, extensive lagoons and two coral atolls.

Another fantastic diving area is the French Pacific Ocean archipelago of New Caledonia. The Lagoons provide habitat to a number of emblematic or threatened marine species such as turtles, whales and dugongs whose population here is the third largest in the world.


Moving to the northern hemisphere, Cocos Island National Park, 550 km off the Pacific coast of Costa Rica, is the only island in the tropical eastern Pacific with a tropical rainforest. The underwater world of the national park is one of the best places in the world to view large pelagic species such as sharks, rays, tuna and dolphins. Also listed in Costa Rica is Guanacaste.


Colombia boasts the Malpelo Fauna and Flora Sanctuary. This vast marine park, the largest no-fishing zone in the Eastern Tropical Pacific, provides a critical habitat for internationally threatened marine species, and is a major source of nutrients resulting in large aggregations of marine biodiversity. It is in particular a ‘reservoir’ for sharks, giant grouper and billfish and is one of the few places in the world where sightings of the short-nosed ragged-toothed shark, a deepwater shark, have been confirmed. Widely recognized as one of the top diving sites in the world, due to the presence of steep walls and caves of outstanding natural beauty, these deep waters support important populations of large predators and pelagic species (e.g. aggregations of over 200 hammerhead sharks and over 1,000 silky sharks, whale sharks and tuna have been recorded) in an undisturbed environment where they maintain natural behavioural patterns.

Finally, Europe also has diveable Marine World Heritage Sites, notably Saint Kilda in Scotland with its oceanic blue water and visibility. The only dive site in Britain which is outside the green coastal waters.

Further Reading:

World Heritage Marine Programme

Will Marine Reserve Protect Coral Sea Sharks?

Although marine protected areas (MPAs) are a common conservation strategy, these areas are often designed with little prior knowledge of whether the species they are designed to protect stay in the area or travel outside it.

Currently, the Coral Sea area and its seamounts in north-east Australia are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans.

In a study published yesterday, researchers conclude that a Marine Protected Area would be effective in protecting reef shark populations at Osprey and Shark Reef in the Coral Sea, but only if fishing of sharks was banned.

The Australian research team investigated the movements of sharks at Osprey Reef, namely whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus.

They found that most individuals showed year round residency at Osprey Reef, although five of the 49 sharks tagged moved to the neighbouring Shark Reef which is 14 km away, and one grey reef shark completed a round trip of 250 km to the Great Barrier Reef. At Osprey Reef adult sharks generally stayed around the north-west corner: the east wall and southern ends were rarely visited.

The Coral Sea region, an area of approximately 972 000 km2, extends east of the Great Barrier Reef Marine Park (GBRMP) to the edge of Australia’s Exclusive Economic Zone. In May 2009, the entire Coral Sea region was declared a Conservation Zone to provide interim protection while the area is being assessed for potential inclusion in the Commonwealth Marine Reserves. Activities taking place in the Coral Sea region, including tourism and commercial and recreational fishing, were allowed to continue.

Since September 2008, there has been a campaign in the Australian community to have the Coral Sea declared a Marine Park. The initial proposal is for a multiple use marine park model for the whole region that promotes sustainable use (where some fishing is allowed), similar to that of the Great Barrier Reef Marine Park. Conservation groups and some scientists have proposed a total no-take model. To date, this no-take proposal has polarized the debate amongst the community and stakeholders.

In the initial proposed multi-use model, our study location, Osprey Reef is listed as a Habitat Protection Zone that would allow limited commercial fishing and recreational fishing.

It is estimated that each year, live-aboard dive boats are directly responsible for generating at least AU$16 M worth of income to the Cairns/Port Douglas region (North Queensland). Of all the Coral Sea reef systems, Osprey Reef has the highest visitation rate by tourism operators, primarily to conduct shark dives. So, the depletion of reef sharks at Osprey Reef would have financial ramifications for tourism in North Queensland. To put this into perspective, in the Maldives, the removal of only 20 grey reef sharks, with a market value of only AU$1 000, caused an estimated loss of AU$500 000 annually in diving revenue.

Further Reading:
Barnett A, Abrantes KG, Seymour J, Fitzpatrick R (2012) Residency and Spatial Use by Reef Sharks of an Isolated Seamount and Its Implications for Conservation. PLoS ONE 7(5): e36574. doi:10.1371/journal.pone.0036574

World-first discovery of hybrid sharks off Australia’s east coast

Scientists have discovered that sharks on Australia’s east coast display a mysterious tendency to interbreed, challenging several accepted scientific theories regarding shark behaviour.

The Australian black tip shark (Carcharhinus tilstoni) and the common black tip shark (C. limbatus) have overlapping distributions along the northern and eastern Australian coastline.

Using both genetic testing and body measurements, 57 hybrid animals were identified from five locations, spanning 2000km from northern NSW to far northern Queensland. Although closely related, the two species grow to different maximum sizes and are genetically distinct.

Dr Jennifer Ovenden, an expert in genetics of fisheries species and a member of the scientific team said this was the first discovery of sharks hybridising and it flagged a warning that other closely related shark and ray species around the world may be doing the same thing.

“Wild hybrids are usually hard to find, so detecting hybrids and their offspring is extraordinary,” Dr Ovenden said.

“To find 57 hybrids along 2000km of coastline is unprecedented.

“Hybridisation could enable the sharks to adapt to environmental change as the smaller Australian black tip currently favours tropical waters in the north.

“While the larger common black tip is more abundant in sub-tropical and temperate waters along the south-eastern Australian coastline.”

Further Reading:
University of Queensland
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