1

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.

2

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 massive study of nearly 1800 tropical coral reefs around the world has found that marine reserves near heavily populated areas struggle to do their job – but are a vast improvement over having no protection at all.

Professor Josh Cinner from the ARC Centre of Excellence for Coral Reef Studies at James Cook University led a team of 37 scientists examining the effectiveness of different reef conservation strategies.

“Fish stocks were extremely depleted on reefs that were accessible to large human populations. Compared to marine reserves far from these human pressures, reserves near high human pressure had only a quarter of the fish and were a hundred times less likely to have top predators such as sharks,” said Professor Cinner.

The scientists also studied how differences in ecological conditions between marine reserves, where fishing is prohibited, and places open to fishing changed as human pressures increased. “This tells you where you can get the biggest impact from implementing conservation,” said Professor Cinner.

“A really novel and exciting part of our study found that the greatest difference in fish biomass between marine reserves and places open to fishing was in locations with medium to high human pressure. This means that, for most fisheries species, marine reserves have the biggest bang where human pressures are medium to high,” he said.

For example, on reefs subject to high human pressure, marine reserves had five times more fish than openly fished reefs – a benefit that can spillover into the depleted fisheries in surrounding areas.

“However, top predators such as sharks were a different kettle of fish,” said co-author Dr Aaron MacNeil from Dalhousie University.

The scientists encountered top predators on less than 30% of their surveys conducted all across the globe, and very rarely in locations where human pressures were high.

“You’d have to do about 200 dives to see a top predator in reserves with the highest human pressure. But where human pressure was low, you’d be likely to see predators more than half the time,” said Dr MacNeil.

Dr Michele Barnes from the ARC Centre of Excellence for Coral Reef Studies at JCU said that in many places, social, economic, and cultural realities mean that marine reserves that entirely prohibit fishing are not an option.

“So, we also looked at how effective other forms of reef conservation were, such as restricting the types of fishing gear that people use. Our results were promising – these restrictions certainly had better outcomes than doing nothing, but not as good as marine reserves. They were a sort of compromise,” she said.

Professor Cinner said the study makes clear the benefits and limitations of implementing key coral reef conservation strategies in different types of locations. “Our research shows where managers will be able to maximise certain goals, such as sustaining top predators or improving the biomass of key fisheries species, and likewise, where they will be wasting their time,” he said.

Citation: Cinner JE, Maire E, Huchery C, MacNeil MA, Graham NAJ, Mora C, McClanahan TR, Barnes ML, Kittinger JN, Hicks CC, D’Agata S, Hoey AS, Gurney GG, Feary DA, Williams ID, Kulbicki M, Vigliola L, Wantiez L, Edgar GJ, Stuart-Smith RD, Sandin SA, Green A, Hardt MJ, Beger M, Friedlander AM, Wilson SK, Brokovich E, Brooks AJ, Cruz-Motta JJ, Booth DJ, Chabanet P, Gough C, Tupper M, Ferse SCA, Sumaila UR, Pardede S, Mouillot D (2018) Gravity of human impacts mediates coral reef conservation gains. Proceedings of the National Academy of Sciences 115:E6116-E6125

Video: here.

 

Contacts:                  

Professor Josh Cinner, CoralCoE at JCU

Mobile +61 417714138 (AEST/UTC +10)

Email: joshua.cinner@jcu.edu.au

 

Dr Michele Barnes, CoralCoE at JCU

Mobile: +61 (0)408677570 (AEST/UTC +10)

Email: michele.barnes@jcu.edu.au

 

Dr Aaron MacNeil, Dalhousie University

Office: +1 (902) 402-1273 (ADT/UTC -3)

Email: a.macneil@Dal.Ca

 

For More Information:

Catherine Naum

Communications Manager, ARC Centre of Excellence for Coral Reef Studies

Office: +61 (0)7 4781 6067 (AEST/UTC +10)

Mobile: +61 (0) 428 785 895

 

Background

The researchers evaluated fish biomass and the presence of top predators on coral reef sites across 41 countries, states, and territories. They used a new way of measuring the human pressures, such as fishing and pollution, to study the effects these are having on fish on the world’s reefs. They developed a ‘human gravity’ scale that calculates factors such as human population size, distance to reefs, and the transport infrastructure on land – which can determine reefs’ accessibility to fishermen and markets.

 

Reports in recent years that marine protected areas (MPAs) aren’t effective in saving coral reefs from the damaging effects of global climate change have led some to argue that such expensive interventions are futile. But a study that spanned 700 kilometers of the eastern Caribbean reveals that MPAs can, indeed, help coral reefs.

An international team of scientists from the University of Maine, USA (UMaine) and the ARC Centre of Excellence for Coral Reef Studies at The University of Queensland, Australia (Coral CoE) conducted research on the leeward islands of the Caribbean and discovered that local reef protection efforts can work — contradicting several previous studies.

Local fisheries management resulted in a 62 percent increase in the density of young corals, which improves the ecosystem’s ability to recover from major impacts like hurricanes and coral bleaching, according to the team’s findings, published in Science Advances, a journal of the American Association for the Advancement of Science.

“MPAs can help coral reefs, but studies to the contrary just weren’t measuring the right things at the right scales,” says lead author and Professor of Marine Biology, Bob Steneck, of UMaine.

“The idea behind MPAs is that, by reducing fishing pressure, you increase the number of seaweed-eating fish, and they decrease the amount of harmful seaweed, which makes it easier for baby corals to get started and thrive on the reef. But coral reefs are complicated, and lots of other things can affect fish numbers, their ability to control the growth of algae and the ability of corals to take advantage of this.”

“Taking field measurements on coral reefs is time consuming, so many researchers are forced to take shortcuts and use simple, widely available data to analyse how reefs respond to protection,” says study co-author Professor Peter Mumby of Coral CoE.

“While it sounds obvious, we show that our ability to detect the benefits of MPAs on corals improves dramatically when you take more detailed measurements,” Prof Mumby says.

“For example, a simple option is to count the number of herbivorous fishes. But if, instead, you estimate how intensively these fishes feed, you obtain a much clearer and compelling insight.”

There is no management panacea for any ecosystem, and especially not for coral reefs, Prof Steneck notes.

“Certainly, stresses on coral reefs from climate and atmospheric changes are serious and beyond direct management control. However, we suggest that local management measures can bolster the recovery of corals after damaging events and, eventually, improve their overall condition.”

Doug Rasher of Bigelow Laboratory for Ocean Science in East Boothbay, Maine, adds: “What we show is that relatively small changes can nudge this ecosystem toward one that can maintain and sustain itself.”

The research team, which also included researchers from James Cook University (Australia) and RARE (USA), concludes that the best way to measure the effectiveness of reef conservation is by using a suite of metrics, including the number of fish, amount of seaweed and the number of baby corals, rather than just one indicator of reef health.

This research was partially funded by the National Geographic Society.

Multimedia resources available here.

Video abstract courtesy of University of Maine here.

Citation: Steneck, RS, Mumby, PJ, MacDonald, C, Rasher, DB, Stoyle, G (2018). Attenuating effects of ecosystem management on coral reefs. Science Advances Vol. 4, no. 5, doi: 10.1126/sciadv.aao5493

 

Contact:

Robert Steneck, steneck@maine.edu (EST)

Peter Mumby, p.j.mumby@uq.edu.au (AEST)

 

For More Information:

Margaret Nagle, nagle@maine.edu (EST)

Catherine Naum, catherine.naum1@jcu.edu.au (AEST)

Jan King, j.king@uq.edu.au (AEST)

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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