Coral Reefs in Danger, Fish Are the Answer

It is no secret that in the midst of climate change, coral reefs around the world are suffering. However, a warming world is not the only factor putting these reefs in danger - overfishing also plagues these colorful ecosystems. And now new research offers a glimmer of hope, finding that fish are the answer to their problems.

According to scientists from the Australian Institute of Marine Science, Wildlife Conservation Society (WCS), James Cook University, and other organizations, fish are the key ingredients in a new recipe to diagnose and restore degraded coral reef ecosystems. At least, in those regions that are severely overfished.

For moderately or lightly fished reefs, success requires knowing which fish to catch, how many, and which to leave behind, the researchers say.

In the journal Nature, 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.

Climate change and ocean acidification - which is diminishing corals like those in the Great Barrier Reef - typically get all the attention. But other important factors are at play as well, such as overfishing, pollution and coastal development.

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. At this rate, this combination of factors could cost the world its coral by the year 2100.

"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," study lead author M. Aaron MacNeil, Senior Research Scientist for the Australian Institute of Marine Science, said in a statement. "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," noted co-author Tim McClanahan, WCS Senior Conservationist. "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." (Scroll to read on...)