How to Save the World's Coral Reefs

Tales of environmental degradation are sadly becoming more common in today's media coverage, and perhaps the most dire stories come from the oceans.

Threats such as warming seas, acidification, deforestation, coastal development and overfishing increasingly threaten the world's corals reefs. Some experts have even predicted an especially attention-grabbing Doomsday scenario: the loss of all reefs due to climate-induced drivers by 2050.

However, empirical data from around the world tells a different story. While heat stress can cause mass mortality of reefs, well-managed reefs can recover and coral organisms themselves have even demonstrated the ability to adapt. While acidification provides a looming threat, some evidence suggests that healthy reefs may even alter the local chemistry of their surrounding waters to ensure proper pH for calcification.

Fortunately, the future of coral reefs can be ensured at least in part by sound management decisions. For instance, many scientists believe local nutrient loading plays an important role in driving ocean acidification. Recent studies have also identified the protection of upland forests and coastal vegetation as critical for the protection of marine ecosystems. Terrestrial ecosystems likewise serve as buffers against large storm events.

Overfishing, however, continues to threaten reefs everywhere and in fact remains the single ubiquitous driver of coral-reef loss today. But overfishing is also a practice that it is within our control to reverse and manage. While it's true that the coral-reef crisis is global, taking action on a local level can curtail much of the damage.

Given the ubiquity of overfishing, two simple strategies should be widely pursued.

The first is to continue the rapid expansion of Marine Protected Areas, where fish biomass can easily exceed 1,000 kg/ha. However, because 73 percent of the world's reefs today sit outside of formal protected areas, it is unrealistic to expect that we can eliminate fishing around reefs, the vast majority of which lie adjacent to developing countries.

Therefore we must work to eliminate overfishing on coral reefs falling outside these fully protected zones. New research released earlier this month by WCS and partners looked at more than 800 coral reefs. This study found that fish biomass must exceed a minimum of 500kg/ha to ensure coral survival. At this level, you find the minimum diversity across functional groups of fish required for coral-reef ecosystems to survive. Below this level, a slow degradation begins.

Alarmingly, the same study revealed that 83 percent of the reefs around the world fell below this threshold. This is unacceptable for a world that more than 20 years ago committed to saving the world's coral reefs.

How do we bring back fish on coral reefs outside of protected areas? Evidence across a range of countries suggests that giving communities the autonomy to manage their own marine resources can elevate fish-biomass levels to the critical 500 kg/ha threshold. Why? Increasing fish biomass on reefs means more food fish can be sustainably harvested for small-scale fisheries.

Coral reefs everywhere need local communities and authorities to have the full legal authority to manage their own reefs with a clear mandate to bring back fish biomass and associated catch to a minimum target of 500 kg/ha outside of protected areas. By following this two-step strategy of expanding MPAs while supporting local communities' initiatives to manage their resources, we can turn things around for the world's corals.

Scientists, conservationists, and fishers around the world have long understood this. But now for the first time we have an empirical target that promises to restore many of the world's degraded reefs and ensure they are best able to handle new threats to the precious oceans that cover nearly three-quarters of our planet.

Caleb McClennen is Executive Director for the Global Marine Program at WCS (Wildlife Conservation Society).

This post is part of a series produced by The Huffington Post in partnership with Ocean Unite, an initiative to unite and activate powerful voices for ocean-conservation action. The series is being produced to coincide with World Oceans Day (June 8), as part of HuffPost's "What's Working" initiative, putting a spotlight on initiatives around the world that are solutions oriented. To read all the posts in the series, read here.