The reasons for this are not entirely understood. The 7,107 islands that make up the Philippine Archipelago constitute the second-largest island chain in the world after Indonesia. The islands converged over millions of years from latitudes as disparate as those of present-day Hong Kong and Borneo, and they may have brought together temperate and tropical fauna that managed to get along in a crowded environment.
Another possible explanation is that the Philippines has a higher concentration of coastline than any country except Norway, providing a lot of habitat. It is also a place where species are evolving more rapidly than elsewhere. Populations become isolated from other populations due to oceanographic features such as swirling currents known as gyres. The populations then diverge genetically and become new species. “The only place on the planet where you have all of the above is in the Central Philippines,” said Carpenter.
A prime location for this diversity is the Verde Island Passage, a busy commercial sea route off Luzon Island, the largest island in the archipelago. During two decades of diving in the Verde Island Passage, Gosliner, the world’s foremost expert in nudibranchs, or sea slugs, has documented more than 800 species, half of them new to science. There are more species of soft corals at just one dive site than in all of the Caribbean. “Every time I go into the water here I see something I’ve never seen before,” he said.
One afternoon, Gosliner emerged from a dive into the shallow water reefs clutching a plastic collection bag that contained two nudibranchs, one colored a bright purple with orange tentacles. “Two new nudis!” he called out. “And the black and electric blue nudibranchs were mating like crazy down there. There were egg masses everywhere. They were having a good ole time.”
Unlike land slugs, nudibranchs have bright colors that advertise toxic chemicals in their skin. These chemicals may have pharmaceutical value, and several are in clinical trials for HIV and cancer drugs. Gosliner explained that the presence of nudibranchs, which feed on a wide variety of sponges and corals, “are a good indication of the health and diversity of the ecosystem.”
The Verde Island Passage ecosystem has faced immense pressures over the past few decades. In the 1970s, Carpenter worked as a Peace Corps volunteer with the Philippines Bureau of Fisheries. “Every 50 feet you’d see a grouper the size of a Volkswagen Bug, big enough to swallow a human being,” he recalls. Today, large predatory fish like sharks are virtually absent. Fishermen now harvest juveniles that haven’t had a chance to reproduce; “it’s at the very level where you can’t get any more fish out of oceans here,” says Carpenter. Destructive fishing methods have devastated the area’s coral. Illegal trade has exacted a further toll; this spring, Filipino officials intercepted a shipment of endangered sea turtles and more than 21,000 pieces of rare black corals bound for mainland Asia, for the jewelry trade.
“There’s a lot of good policies and regulations in place in the country, but the main weakness right now is enforcement,” says Romeo Trono, country director for Conservation International.
The Philippines has more than 1,000 marine protected areas, more than any country in the world, but only a few, Carpenter and other scientists say, are well managed. For 30 years, Apo Island, in the southern Philippines, has been held as a model for community-managed marine reserves. In 1982 a local university suggested the community declare 10 percent of the waters around the island a “no take” zone for fishermen. Initially resistant, the community eventually rallied behind the reserve after seeing how an increase in fish numbers and sizes inside the sanctuary spilled over into the surrounding waters. They established regulations against destructive fishing and a volunteer "marine guard" (called bantay dagat) to patrol the fishing grounds and prevent encroaching from outsiders. User fees from the marine sanctuary generate nearly $120,000 per year, and the tourist industry surged after the marine ecosystem recovered.
“Where marine protected areas have been established and populations of animals and fishes have been allowed to recover, they recover very well and very quickly,” says Gosliner. “The difference between diving in a marine protected area versus an area right next to it is like night and day.”
Over the next several months, California Academy scientists will use microscopes and DNA sequencing to confirm and describe these new species. The species lists and distribution maps created during the expedition, they hope, will help to identify the most important locations for establishing or expanding marine protected areas, as well as areas for reforestation that will reduce erosion and subsequent sedimentation damage to the reefs.