Los Angeles, California – Coral reefs in the Indo-Pacific have largely recovered from the devastating hot water die off or “bleaching event” that killed up to ninety percent of corals on some reefs in 1998. In a presentation made today at the International Coral Reef Symposium in Fort Lauderdale, Florida, Reef Check coral reef ecologist Gregor Hodgson reported that ten years later, recovery has occurred more quickly and more completely than expected. Caribbean reefs, however, are losing about three percent living coral every four years due to a combination of human impacts.
According to Hodgson, “When the devastating 1998 bleaching event occurred and the extent of dead coral was tallied, many scientists feared that the dead reefs would not recover, and that the remaining live reefs could be killed if such intense bleaching events continued.”
Although smaller bleaching events have occurred, the damaged reefs began to slowly recover. New larval corals settled and began to grow. Now some of these corals measure more than 1 meter in diameter and carpet the previously damaged reefs such as in the Maldives.
In 2005, another large bleaching event occurred in the Caribbean; however, much less damage was recorded. Reef Check scientists believe that this is because species such as branching staghorn and elkhorn corals were already decimated due to other factors in the 1980s. The remaining corals may be more resistant to being killed by bleaching.
In a related publication which appears in today’s journal Science, Hodgson and co-authors assessed the conservation status of 845 reef-building coral species using the International Union for the Conservation of Nature’s Red List Criteria. Of the 704 species examined, 231 are listed within the "Threatened" categories of "Vulnerable", "Endangered", or "Critically Endangered", while another 176 are considered “Near Threatened”. The proportion of corals threatened with extinction has increased dramatically in recent decades and exceeds most terrestrial groups. If coral reefs collapse, this will lead to a large- scale loss of biodiversity and economic losses of nearly $400 billion per year.
“On the scale of a decade, Reef Check data show that coral reefs can recover following damage,” says Hodgson. “Looking ahead several decades, however, a combination of threats – global warming, seawater acidification, and overfishing that are destabilizing coral reef ecosystems – raise the risk of extinction.” The Caribbean has the largest proportion of corals in high extinction risk categories while the Coral Triangle (western Pacific) has the highest proportion of species in all categories of elevated extinction risk.
Founded in 1996, the Reef Check Foundation is an international non-profit organization dedicated to conservation of two ecosystems: tropical coral reefs and California rocky reefs. Based in Los Angeles Reef Check teams in more than 80 countries create partnerships among community volunteers, government agencies, businesses, universities, and other non-profits. The goal is to educate the public about the value of reef ecosystems and the current crisis affecting marine life as well as to create a global network of trained volunteer diving teams who regularly monitor and report on reef status in support of science-based conservation.