Scientists Have Found a New Way to Save the World’s Coral Reefs, and It’s Pretty Fishy

The secret to a healthy coral reef is a healthy population of fish, a new study has found.

The study, published this week in Nature, looked at the fish biomass — the total mass of all fish species in a reef — of 832 reefs around the world, and used data on the reefs’ health to estimate the levels of fish biomass needed to sustain that health.

The researches found that reefs with no fishing had about 1,000 kilograms (2,204 pounds) of fish biomass per hectare (2.47 acres), and that to avoid a total collapse of ecosystem health, reefs needed to stay above a minimum of 100 kgs (about 220 lbs) of fish biomass per hectare. To keep their ecosystems healthy and be able to sustain fishing needs, reefs needed to keep fish biomass at at least 500 kgs (1,102 lbs) of fish biomass per hectare.

Unfortunately, according to the study, most of the world’s coral reefs aren’t succeeding at maintaining this biomass level.  The researchers found that 83 percent of the coral reefs studied didn’t have a fish biomass of 1,102 lbs per 2.47 acres.  But this doesn’t mean those reefs can’t still recover, said Aaron MacNeil, lead author of the study and senior research scientist for the Australian Institute of Marine Science.

MacNeil told ThinkProgress in an email that, because of the wide range of regulatory measures that can be put in place to regulate fishing methods or limit the amount or type of fish taken from a region, even poorer countries can take steps to improve their reef health.
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But even though the benefits of fishing restrictions can be seen in reefs within a decade or so, the study said heavily-fished reefs that have seen their fish stock severely depleted would need about 59 years to recover completely under fishing restrictions.  Averagely-fished reefs would need about 35 years.
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Despite the study’s confirmation that more fish leads to a healthier reef, and that there are many steps regions can take to protect their reefs, the authors write that marine reserves and fishing regulations aren’t enough to combat the threats reefs face from climate change and ocean acidification.

“Addressing the coral reef crisis ultimately demands long-term, international action on a global-scale issues such as ocean warming and acidification,” the study reads.

Still, better management will likely help reefs be more resilient to these challenges in the future.  A report last year found that coral reefs protected from stressors like pollution and overfishing can bounce back from warming-induced events like bleaching.

Read more at Scientists Have Found a New Way to Save the World’s Coral Reefs, and It’s Pretty Fishy