Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Recipe for saving coral reefs: Add more fish

09.04.2015

Scientists seek to ensure survival of coral reefs outside of protected areas by calling for a minimum target of 500 kilograms of fish biomass per hectare

Fish are the key ingredients in a new recipe to diagnose and restore degraded coral reef ecosystems, according to scientists from the Australian Institute of Marine Science, WCS, James Cook University, and other organizations in a new study in the journal Nature.


Redfin butterflyfish in their coral reef habitat. Fish are the key ingredients in a new recipe to diagnose and restore degraded coral reef ecosystems, according to scientists from the Australian Institute of Marine Science, the WCS, James Cook University, and other organizations in a new study in the journal Nature.

Credit: Tim McClanahan/WCS

For overfished coral reef systems, restoring fish populations that perform key roles will in turn restore ecological functions critical to recovery. For moderately or lightly fished reefs, the recipe requires knowing which fish to catch, how many, and which to leave behind.

The authors assessed fish biomass and functional groups from more than 800 coral reefs worldwide and used them to estimate recovery periods for both lightly fished and overfished reefs. The scientists speculate that maintaining and restoring fish populations and the functions they provide can increase the resilience of reefs to large-scale threats such as climate change.

The coral reefs of the world are in crisis, endangered by a number of coastal threats such as overfishing, pollution, and coastal development as well as global threats such as climate change. According to the World Resources Institute, some 75 percent of the world's coral reefs are now threatened and more than 20 percent have disappeared since climate and fishing disturbances have accelerated in the past 30 years. At the same time, only 27 percent of the world's coral reefs are contained within marine protected areas.

"By studying remote and marine protected areas, we were able to estimate how much fish there would be on coral reefs without fishing, as well as how long it should take newly protected areas to recover," said M. Aaron MacNeil, Senior Research Scientist for the Australian Institute of Marine Science and lead author on the study. "This is important because we can now gauge the impact reef fisheries have had historically and make informed management decisions that include time frames for recovery."

"The methods used to estimate reef health in this study are simple enough that most fishers and managers can take the weight and pulse of their reef and keep it in the healthy range," said Tim McClanahan, WCS Senior Conservationist and a co-author on the study. "Fishers and managers now have the ability to map out a plan for recovery of reef health that will give them the best chance to adapt to climate change."

Coral reef experts agree that fishing is a primary driver in the degradation of reef function, which in turn has generated growing interest in finding fisheries management solutions to support reef resilience. Removing too many herbivorous and predatory fish species deprives coral reefs of critical ecosystem functions and the capacity to respond effectively to other disturbances. Knowing the right amount to leave behind can help local fisheries set clear limits to how many fish can be taken without threatening the ecosystem they rely on.

In response to this need, the study authors have created the first empirical estimate of coral reef fisheries recovery potential using data from 832 coral reefs in 64 locations around the world. The analysis included marine reserves and fishing closures as a control for estimating healthy fish biomass along with numerous sites along a spectrum of fishing intensity, from heavily fished reefs in the Caribbean to locations with low fishing rates and high fish "biomass" such as the Easter Islands. Despite the breadth of the data, some simple and consistent numbers emerged from the study.

Some of the key metrics uncovered in the study:

  • According to the analysis, a coral reef with no fishing averages 1,000 kilograms per hectare of fish biomass.

     

  • The fish biomass threshold for a collapsed reef--overfished to the point of nearly total ecosystem failure--is 100 kilograms per hectare.

     

  • The most degraded reefs lack browsers (rudderfish, parrotfish, and surgeonfish), scraper/excavators (parrotfish), grazers (rabbitfish, damselfish), and planktivores (fusiliers), so the first steps in reef recovery depends on allowing these species and the services they provide to return.

     

  • Coral reefs that maintained 500 kilograms of fish biomass per hectare (about 50 percent of an average reef's carrying capacity) were found to maintain ecological functions while sustaining local fisheries, providing fishers and marine managers with a critical target.

     

  • The authors found that 83 percent of the 832 reefs surveyed contained less than the 500 kilogram fish biomass threshold needed to maintain ecological integrity and stave off decline.

     

  • The models generated time estimates needed for both unregulated and partially regulated coral reef fisheries to recovery; a moderately fished coral reef system can recover within approximately 35 years on average, while the most depleted ecosystems may take as long as 59 years with adequate protection.

     

The study also highlights the benefits of alternative fisheries restrictions, including bans on specific fishing gear such as small-mesh nets and restrictions on herbivorous species. Approximately 64 percent of coral reefs with fishing regulations (including bans on specific fishing gear such as small-mesh nets and restrictions on fishing of herbivorous species) were found to maintain more than 50 percent of their potential fish biomass.

"Reef fish play a range of important roles in the functioning of coral reef ecosystems, for example by grazing algae and controlling coral-eating invertebrates, that help to maintain the ecosystem as a whole," said coauthor Nick Graham of James Cook University. "By linking fisheries to ecology, we can now make informed statements about ecosystem function at a given level of fish biomass."

"The finding that gear restrictions, species selection or local customs can also contribute to fish population recovery is compelling. It demonstrates that managers can use a range of different management strategies in areas where it may not be culturally feasible to establish permanent marine reserves," said coauthor Stacy Jupiter, WCS Melanesia Program Director. "Having a portfolio of management options provides flexibility to respond to local social and economic contexts. However, only completely closed no-take marine reserves successfully returned large predatory fish to the ecosystem."

###

YouTube video related to this story: https://www.youtube.com/watch?v=fDzMzyWZxL8&feature=youtu.be (Credit: WCS)
Fish are the key ingredients in a new recipe to diagnose and restore degraded coral reef ecosystems, according to scientists from the Australian Institute of Marine Science, WCS, James Cook University, and other organizations in a new study in the journal Nature.

This study was generously supported by the John D. and Catherine T. MacArthur Foundation, the Australian Institute of Marine Science, and the ARC Centre of Excellence for Coral Reef Studies.

The authors of the paper titled "Recovery potential of the world's coral reef fishes" are: M. Aaron MacNeil of the Australian Institute of Marine Science; Nicholas A.J. Graham and Joshua E. Cinner of James Cook University; Shaun K. Wilson of the Australian Department of Parks and Wildlife; Ivor D. Williams of the NOAA Pacific Islands Fisheries Science Center; Joseph Maina of the Wildlife Conservation Society and Newcastle University; Steven Newman of Newcastle University; Alan M. Friedlander of the University of Hawaii; Stacy Jupiter of the Wildlife Conservation Society; Nicholas V.C. Polunin of Newcastle University; and Tim R. McClanahan of the Wildlife Conservation Society.

Media Contact

John Delaney
jdelaney@wcs.org
718-220-3275

 @TheWCS

http://www.wcs.org 

John Delaney | EurekAlert!

Further reports about: Ecosystem Marine WCS Wildlife Wildlife Conservation Society biomass coral reef fishing

More articles from Ecology, The Environment and Conservation:

nachricht Scientists on the road to discovering impact of urban road dust
18.01.2018 | University of Alberta

nachricht Gran Chaco: Biodiversity at High Risk
17.01.2018 | Humboldt-Universität zu Berlin

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>