I’m in Palau for two weeks researching a couple of things for the book I’m working on.
I was in Palau in 1995 while researching Song for the Blue Ocean. It seemed like nearly untouched paradise then. It’s more crowded now in the main town, and some of the most popular dive sites are in danger of getting overcrowded. But biologically it remains a terrific place. There are still plenty of sharks, sea turtles, big Napoleon wrasses, lots of great coral, and blizzards of reef fishes in many places. Scenically, it remains fantastically beautiful, its exquisite Rock Islands still un-built-upon and unspoiled.
The first week of this visit I’ve spent diving with Bob Steneck of the University of Maine, his PhD student Susie Arnold, Peter Mumby of Exeter in England, and Rob van Woesik of Florida Institute of Technology. These folks are coral reef scientific superstars. They are examining patterns of recovery of coral reefs since the heavy die-off caused by excessively warm water during 1998.
Good news for a change: On many reefs in this world-class country of corals, the amount of live coral has increased dramatically in the last decade. The extent of live coral coverage on many of Palau’s reefs has increased from about 5 percent after the die-off to 50 and even up to 70 percent on many reefs now.
Importantly, Palau has probably the best recovery of all the reefs that have degraded over a wide swath of the tropics. Vast areas coral reefs of the Indian Ocean, Australia, and west and south Pacific died back in the 1998 heat-wave. Caribbean reefs have-in general, and with the main exception of Bonaire-declined substantially in the last 25 years, with most branching corals collapsed and largely replaced by algae. Few have recovered. Will they ever recover? No one can say. But in the Pacific, Palau is recovering well.
The question: Why? Though the research is ongoing and the story still unfolding, the answer seems to be: Palau made it illegal to export reef fish. So the reefs here have plenty of fish capable of grazing algae that moves in when corals die. Without those grazing fish, dead coral gets overtaken by algae. Algae prevent coral from getting re-established. So the reef flips from a coral reef to an algae reef. If the grazing fish are there in high enough numbers, they can mow the algae, letting corals recover.
Bonaire, with perhaps the most healthy reefs in the Caribbean, has also done a good job of protecting grazing fish. They too have healthy coral reefs.
So the bottom line seems to be: Coral reefs need fish. Overfishing isn’t just bad for the fish; ultimately it facilitates collapse of the reefs themselves.
The other question: In a warming world, when, and how frequently, will the next coral-killing heat-waves strike?