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.
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|Contact: Nick Graham|
ARC Centre of Excellence in Coral Reef Studies