Warm oceans are a call to action to keep reefs healthy

I jumped into the water recently off the Kohala coast in West Hawaii, expecting a refreshing reprieve from a long day working in the sun. What I got instead was a warm water bath that was more disturbing than it was invigorating.

My guess is that anyone else who has jumped in the ocean lately has also experienced firsthand what was just reported — Hawaii’s waters are getting hotter. What you may not know is that this hot water is taking a toll on the coral reefs that are so integral to our life and culture in these islands.

Whether we realize it or not, we all rely on coral reefs in so many ways: for the fishing and surfing that define our island lifestyle, for sustenance and cultural practice that connect us to our past, for recreation and tourism that support our local economy, and as a buffer to slow wave energy and protect our shores — to name just a few.

But this year our reefs face a new challenge. Recent news reports have predicted severe coral bleaching on Hawaii’s reefs. Bleaching is a coral’s response to stress — in this case caused by rising sea surface temperatures, which are already 3 to 6 degrees Fahrenheit warmer than usual. And that is bad news for coral reefs, which can start bleaching with just a 2-degree F increase in temperature. When corals are stressed, they release the symbiotic algae (zooxanthellae) that gives them color and on which they rely for nutrition. The longer they remain stressed, the more vulnerable they are to disease, starvation and death.

But a reef that is healthy at the start is more likely to survive a bleaching event like the one we are experiencing right now. Just like humans, healthier reefs are better able to ward off illness. Scientists call this “reef resilience,” and have been studying what makes reefs more resilient since the 1998 El Niño, which caused severe coral bleaching around the globe.

Reefs that did not bleach and those that recovered shared certain characteristics, such as healthy fish populations, proximity to cold water upwelling, shading or the natural resistance of certain coral species. Hawaii didn’t experience bleaching in 1998 because of the cool ocean currents that until this year have largely protected us from warming waters.

The good news is that there are things we can do to make Hawaii’s reefs more resilient. Most importantly, we can manage the local stressors that are under our control — reducing pollution, runoff, invasive algae and overfishing to make our reefs as healthy as possible.

We can also identify those areas that are naturally resilient, and prioritize them for community- based management.

Gov. David Ige recently signed into law the state’s first community-based subsistence fishing area for Haena, Kauai, giving that community the ability and responsibility to manage its reefs.

There are now four more communities on Molokai, Maui and Hawaii island asking for that same responsibility. It is more important than ever to support communities like these that are working to help government agencies keep our reefs healthy so that they are better able to withstand the global challenges of warming waters and rising seas.

As the Hawaiian proverb says: E Ola Ke Kai, E Ola Kakou … As the ocean thrives, so do we.