Please select your home edition
Edition
Wildwind 2016 728x90

World-first discovery 'can help save coral reefs'

by ARC Centre of Excellence for Coral Reef Studies on 4 Oct 2011
An area of high coral cover on the Far North Great Barrier Reef - Eric G Matson Australian Institute of Marine Science (AIMS) http://www.aims.gov.au/creefs
An international team of scientists has achieved a major breakthrough in fishing sustainability on coral reefs which could play a vital role in preventing their collapse.

'Fishermen and scientists have long wondered how many fish can be taken off a reef before it collapses, says Dr Nick Graham of the ARC Centre of Excellence (ARC CoE) for Coral Reef Studies and James Cook University.

'The consequences of overfishing can be severe to the ecosystem and may take decades to recover, but hundreds of millions of people depend on reefs for food and livelihoods, so banning fishing altogether isn’t a reality in many nations.'

In a report in today’s issue of the Proceedings of the National Academy of Sciences of the USA (PNAS) the researchers demonstrate how overfishing can generate a predictable sequence of events that lead to the collapse of reef ecosystems.

Their research offers a vital new tool for managing corals reefs and tropical fisheries worldwide, providing clear targets for sustainability that can help reef fisheries support the very resource they depend on.

'Our work shows that as fish biomass – the number and weight of fish living on a reef – declines due to fishing pressure, you cross a succession of thresholds, or tipping points, from which it is increasingly hard to get back,' Dr Graham explains..

'For example, you see patches of weeds replacing coral, you see more sea urchins devouring the coral, you see a general decline in the species richness on the reef, and you see less coral cover.

'The loss of hard corals is actually the last stage in the collapse of the reef system. Though many people take it as a major warning sign, in fact, by the time you see the loss of live coral cover, it may be already too late to save the reef.'

The study shows that in well-protected areas, there are typically 1000-1500 kilos of reef fish of various species per hectare of coral reef.

As the volume is fished down below 1000 kilos, the early warning signs – like increased seaweed growth and urchin activity, begin to show up.

The researchers found that between 300-600 kilos/ha there appeared to be a window of what is known as maximum sustainable yield, but when the fish stock drops below 300 kilos/ha the reef is in real trouble, they say.

Dr Aaron MacNeil from the Australian Institute of Marine Science adds: 'This information is critical to policy makers and reef managers: if fish stocks can be maintained at a certain level, the chances of retaining a sustainable fishery and a healthy reef system are greatly improved.

'It’s a way of understanding the health of the whole system, not just parts of it,' he says. 'It offers managers a tangible target for protecting both the fishery and the reef, and it supports the need for long-term monitoring of fish in places such as the Great Barrier Reef.'

'Of course, having a target is one thing, but achieving it is, well, another kettle of fish' adds Dr Joshua Cinner, also from the ARC CoE. 'So we also assessed how well different reef management schemes did at maintaining reefs within or above this sustainability window.

Reef fisheries with no regulations tended to perform poorly, with some completely collapsed. No-take marine reserves, where fishing was prohibited were the best performers and tended to maintain key ecosystem processes, such as predation.

'But people depend on reefs for their livelihoods, so we can’t prohibit fishing everywhere.' notes Dr. Cinner. 'A key finding from our study was that even easily enforceable regulations that restrict gear or the types of species that can be caught helped maintain biomass. These regulations are often more palatable to fishermen than no-take closures and consequently receive higher levels of support and compliance.'

The researchers point out their work was carried out on Indian Ocean coral reefs, and needs to be confirmed in the Pacific and Great Barrier Reef regions – however they are confident a similar relationship exists between the volume of fish and overall reef health. Similar relationships may also apply in other ecosystems.

Their paper Critical thresholds and tangible targets for ecosystem-based management of coral reef fisheries by Tim R. McClanahan, Nicholas A. J. Graham, M. Aaron MacNeil, Nyawira A. Muthiga, Joshua E. Cinner, J. Henrich Bruggemann and Shaun K. Wilson is published in this week’s online edition of the Proceedings of the National Academy of Sciences of the USA.

ARC Centre of Excellence for Coral Reef Studies website
PredictWind.comWildwind 2016 660x82Southern Spars - 100

Related Articles

A Few Rays - What is Broad Spectrum Protection?
What is Broad Spectrum sunscreen? Ultraviolet rays only make up a small proportion of all of the sun’s rays. What is Broad Spectrum sunscreen? Ultraviolet rays (UVA, UVB and UVC) only make up a small proportion of all of the sun’s rays. UVA and UVB sun-rays are however the biggest contributors to skin damage from sun.
Posted on 19 Apr
Frigid flying – Coast Guard aircrews take on New England Winter
Freezing rain? Teeth-chattering temperatures? Limited visibility? Coast Guard aircrews are still ready to fly. Freezing rain? Teeth-chattering temperatures? Limited visibility? Coast Guard aircrews are still ready to fly. At Air Station Cape Cod, aviation maintenance and electronic technicians work around the clock to ensure the MH-60 Jayhawk helicopters are prepared and ready to launch. There is one thing the maintenance crews and pilots cannot control: winter weather.
Posted on 9 Feb
When whales meet sails
CAMPER helmsman Roberto ‘Chuny’ Bermudez found himself nearly face to face with whale in middle of North Atlantic Ocean. Currently the database for marine mammal strikes is very sparse. We are requesting sailors and boaters help to submit information on current and past incidents, however long ago that may be. By giving a location, date, identification if possible, and any other relevant information you can help scientists better understand where marine mammals are at risk for strikes
Posted on 8 Jan
Vendée Globe – Uncertainty about weather condition in North Atlantic
Alex Thomson and Armel le Cléac'h are probably looking closely at the wind models for the North Atlantic. Alex Thomson and Armel le Cléac'h are probably looking closely at the wind models for the North Atlantic. It does not seem to be easy.
Posted on 4 Jan
10,000 metric tons of plastic enter Great Lakes every year
A new study inventories and tracks high concentrations of plastic in Great Lakes could help inform cleanup efforts A new study by Rochester Institute of Technology that inventories and tracks high concentrations of plastic in the Great Lakes could help inform cleanup efforts and target pollution prevention.Researchers found that nearly 10,000 metric tons—or 22 million pounds—of plastic debris enter the Great Lakes every year from the United States and Canada.
Posted on 2 Jan
The Deepwater Horizon aftermath
Researchers analyze 125 compounds from oil spilled in Gulf of Mexico to determine their longevity at different levels. Researchers analyze 125 compounds from oil spilled in the Gulf of Mexico to determine their longevity at different contamination levels. The oil discharged into the Gulf of Mexico following the explosion and sinking of the Deepwater Horizon (DWH) rig in 2010 contaminated more than 1,000 square miles of seafloor.
Posted on 1 Jan
What happened to Deepwater Horizon Oil?
What happened to the 160 million gallons of oil that gushed for 87 days into the Gulf of Mexico in 2010? Six years after the Deepwater Horizon oil spill, we are continually asked two questions. What happened to the 160 million gallons of oil that gushed for 87 days into the Gulf of Mexico in 2010? Was discharging 1.67 million gallons of chemicals into the ocean to disperse the oil a good or bad idea?
Posted on 24 Dec 2016
Vendée Globe – Light winds for Banque Populaire and Hugo Boss
The first one to get out of it will have a nice north-westerly flow on the edge of the high pressure system. Banque Populaire and Hugo Boss are sailing in a complex weather system in a light wind zone. The first one to get out of it will have a nice north-westerly flow on the edge of the high pressure system.
Posted on 15 Dec 2016
Great Barrier Reef managers and industry prepare for summer
Marine park managers, scientists and experts recently met for the annual pre-summer workshop Marine park managers, scientists and experts recently met for the annual pre-summer workshop to assess climate-related risks to the Great Barrier Reef over the coming months. Current predictions by the Bureau of Meteorology and National Oceanic and Atmospheric Administration are for a summer of average sea temperatures across the Great Barrier Reef.
Posted on 7 Dec 2016
Fourth Blog from on board Perie Banou II
Oh no - not the coffee cup Oh no - not the coffee cup - Jon keeps us all entertained as he approaches Reunion Island. The B&G chartplotter tells me since leaving the pleasant mid Western Australian town of Carnarvon (by world standards, an isolated town), that I have sailed some 2559 NM and have 751nm to go to Le Port Reunion Island. French. Reunion is a Suburb (department) of Paris. Population 844,000.
Posted on 23 Nov 2016