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People and ecosystems

Understanding of the links between coral reef ecosystems, the goods and services they provide to people, and the wellbeing of human societies.

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Ecosystem dynamics: past, present and future

Examining the multi-scale dynamics of reefs, from population dynamics to macroevolution

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Responding to a changing world

Advancing the fundamental understanding of the key processes underpinning reef resilience.

Coral Bleaching

Coral Bleaching

Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au

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A new and significant role for marine reserves on the Great Barrier Reef has been revealed, with researchers finding the reserves reduce the prevalence of coral diseases.

It’s been known for some time that marine reserves are important for maintaining and enhancing fish stocks, but this is the first time marine reserves have been shown to enhance coral health on the Great Barrier Reef.

Researchers from the ARC Centre of Excellence for Coral Reef Studies at James Cook University found that coral disease levels were four times lower inside no-take marine reserves, where fishing is banned, compared to outside reserves.

Discarded fishing line caught on Great Barrier Reef coral. Image: Joleah Lamb.

“We surveyed more than 80,000 corals around the Whitsunday Islands for six different diseases that commonly harm reef corals around the world,” says study lead author, Dr Joleah Lamb from the Coral CoE.

“We found three coral diseases were more prevalent on reefs outside no-take marine reserves, particularly on reefs with high levels of injured corals and discarded fishing line.”

Wounded corals are more vulnerable to disease. Damaged tissue provides sites where pathogens and parasites can invade, particularly as coral immune responses are lowered while they heal.

Dr Lamb says once a pathogen infects a coral, tissue loss typically spreads from the point of entry.

“It’s like getting gangrene on your foot and there is nothing you can do to stop it from affecting your leg and ultimately your whole body.”

“Disease outbreaks can take a heavy toll, with losses of up to 95 per cent of coral cover on some reefs in the Caribbean.”

Given the difficulty identifying pathogens that cause disease, the researchers say it’s vital to understand which activities increase the risk of coral diseases, and to protect against them.

They say discarded fishing line and levels of coral breakage, potentially from a variety of fishing-related activities, outside the no-take zones on the Great Barrier Reef are indicators of the types of activities that contribute to the problem.

Researchers survey coral on the Great Barrier Reef. Image: Joleah Lamb.

“Fishing line not only causes coral tissue injuries and skeleton damage, but also provides an additional surface for potential pathogens to colonise, increasing their capacity to infect wounds caused by entangled fishing line,” Dr Lamb says.

The researchers hope their findings send a clear message to reef managers about the benefits of marine reserves for coral health.

“No take marine reserves are a promising approach for mitigating coral disease in locations where the concentration or intensity of fishing effort is relatively high,” says Professor Garry Russ from the Coral CoE.

Professor Bette Willis, also from the Coral CoE, says the scientists are now expanding their research to examine other drivers of coral disease.

“We’ve shown that there are strong links between damage and disease in this study, now we’re interested in understanding and managing other potential drivers of diseases that involve injury– such as outbreaks of crown-of-thorns starfish, cyclones, and recreational activities like anchoring.”

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Paper: Lamb JB, Williamson DH, Russ GR, and BL Willis (In Press). Protected areas mitigate diseases of reef-building corals by reducing damage from fishing. Ecology. DOI:10.1890/14-1952.1

http://www.esajournals.org/doi/abs/10.1890/14-1952.1

Contacts:

Dr Joleah Lamb – Joleah.Lamb@my.jcu.edu.au, +61 (0) 4 59 040 091

Professor Bette Willis – Bette.Willis@jcu.edu.au, +61 (0) 7 4781 5349

Australia can be a world leader in designing marine reserves that keep pace with changes in the climate and human activity and still successfully protect their sea life, a leading marine scientist said today.

Professor Bob Pressey of the ARC Centre of Excellence for Coral Reef Studies and James Cook University told the Australian Academy of Science’s Earth System Outlook Conference in Canberra that developing marine protected areas that can absorb the impact of warming oceans, storms and flood events from the land is ‘doable’.

His comments come as government leaders from around the world meet in Doha for the United Nation’s Climate Conference (Nov 26-Dec7) to try to impart new momentum to stalled efforts to fight climate change.

“The challenge we face is that a marine reserve or park usually covers a fixed geographical area – but bodies of hot ocean water, storms and flood runoff move unpredictably in space and time,” Prof. Pressey explains.

“This means either that the reserve boundaries may have to move as things change – or else they need to located and designed carefully. If they’re fixed reserves, they need to be placed away from frequent disturbances, or configured so that individual disturbance events don’t affect them entirely. That way, we can include areas where sea life may take refuge to be safe from the impact.”

Prof. Pressey says that 25 years of ocean temperature data had given scientists a much better understanding of where on the Great Barrier Reef the impacts of coral bleaching were likely to be most severe – and where corals appeared to be consistently safe from high temperatures.

“While we can’t easily predict when an episode of hot ocean water will move in, we can definitely see some areas which appear to avoid the harshest effects over time – whether because they are shielded in some way or cooled by cold upwelling currents.

“This gives us the ability to design marine protected areas for the GBR and elsewhere that are resilient over time, no matter what changes take place.

“On top of the sea temperatures, we can also potentially factor in historical data from cyclone tracks and flood plumes, or bodies of floodwater with high loads of sediment. By superimposing all these we can identify and be sure to protect those special areas of the reef which are naturally resilient and which can recharge other areas that may be damaged.”

In a separate paper to the conference Professor Geoff Jones of CoECRS and JCU said there was now plenty of evidence that marine reserves work – not only by replenishing fish populations in no-take zones, but also by recharging fish populations in areas open to fishing.

“Our a new application of genetic parentage analysis shows protected populations of coral trout are helping to sustain juvenile recruitment in both reserves and in fished populations,” he says.

“At the Keppel islands, local reserves (about 30% of the reef area) now account for about 60% of juvenile recruitment of coral trout in the region, both in reserves and fished areas.  Hence, reserves do have the potential to conserve coral trout and sustain fisheries in the long-term.”

However Prof. Jones cautioned that coral trout populations could still suffer if coral cover on the reef declined – and added that size and catch limits would still be needed in areas outside the reserve to ensure there were enough adult fish to sustain the fishery.

“While no take zones are extremely valuable, we need both them and more traditional fisheries management practices to ensure a healthy fish population on the Great Barrier Reef into the future,” he concluded.
 

More information:

Professor Bob Pressey, CoECRS and JCU +61 7 4781 6194 or +61 0418 387 681
Professor Geoff Jones, CoECRS and JCU, + 61 7 4781 4559 or +61 0435 065 296
Jenny Lappin, CoECRS, +61 7 4781 4222
Jim O’Brien, James Cook University Media Office, +61 7 4781 4822 or +61 0418 892 449
Mona Akbari, Media Officer AAS, ph +61 2 6201 9452

 

https://www.coralcoe.org.au/

 

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Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au