Indo-Pacific Coral Decline Over Time, Extent, and Region

It shouldn’t come as news that corals aren’t doing so well these days. Between warming waters, overfishing, and ocean acidification, coral reefs are facing a barrage of man-made impacts that threaten to wipe out these communities across the globe. Just recently, NOAA announced that we are currently facing the third worldwide coral bleaching event in history. And while certain areas with high coral cover are very well-studied, we still lack data on many coral reefs in remote regions of the ocean. The Indo-Pacific is a highly biodiverse marine environment that is home to approximately75% of the world’s coral reefs. However, there isn’t much information on how these reefs have changed over time and how we can expect them to fare over the next century.

In 2007, a couple of researchers out of the University of North Carolina Chapel Hill sought to fill this gap in our knowledge. Dr. John Bruno and Dr. Elizabeth Selig examined 6,001 quantitative surveys of 2,667 coral reefs in the Indo-Pacific region from 1968-2004 to measure just how much these habitats are changing. The team’s research, published in the open-access journal PLOS One, found that coral covered only about 22% of the area surveyed and that in 2003 only 7 of 390 surveyed reefs had coral cover over 60%. Over the last forty years, it’s estimated that coral cover has declined between 0.7-2%, with the rate most likely increasing in the last decade.

This decrease in coral cover has significant detrimental implications for the Indo-Pacific region. As I mentioned earlier, the area contains approximately 75% of the world’s coral reefs. Any overall decline in coral cover would seem to indicate a substantial threat to these habitats and marine biodiversity in general. Coral reefs form the basis of diverse and productive marine ecosystems, and without a strong foundation the entire system is at risk of collapsing. Additionally, the Indo-Pacific is home to many small island nations whose way of life is contingent on healthy oceans for their way of life. A decline in coral cover means that food will become scarce (as fish become scarcer), ecotourism will decline, and shorelines will be more susceptible to erosion and storm damage.

Therefore, we must make a global effort to protect and more effectively manage our coral reefs. By collecting more current data on their abundance in specific areas, we can better estimate the productivity and resilience of these marine habitats. Additionally, we can more effectively develop restoration and conservation efforts to ensure corals don’t succumb to rising sea surface temperatures and ocean acidification. The good news is that coral restoration is critical on all levels, from local efforts to reduce plastic pollution and transplant corals to large-scale monitoring efforts along an entire shoreline all the way up to establishing marine protected areas.

Enjoy the Podcast!