On the morning of March 30, fishermen casting their nets in the Burias Pass, a centrally located channel in the Philippine archipelago, got the catch—not to mention surprise—of their lives: a megamouth shark so rare that some people still consider it a "cryptid", a creature that is seen so infrequently science can't confirm its existence.
That's likely an overstatement when it comes to the megamouth, first spotted in 1976 in waters near the Hawaiian island of Oahu. But, according to the Florida Museum of Natural History (FLMNH) in Gainesville, which dubbed last month's catch "megamouth 41" (this being only the 41st observation of one of these sharks)—this is the eighth specimen snagged in the Pacific Ocean near the Philippines.
The docile leviathan, measuring 13 feet (four meters) in length and weighing in at about 1,100 pounds (500 kilograms), died after becoming entangled in the nets. The anglers brought it back to the municipality of Donsol where, over the objections of the local chapter of the World Wildlife Fund (WWF–Philippines), they butchered it for food. (Shark is considered a delicacy in the Philippines.)
"Whale and megamouth sharks, manta rays, dolphins, and other charismatic giants indicate that the region’s ecosystem is still relatively healthy," Elson Aca, a WWF–Philippines project manager who identified the carcass as that of a megamouth, said in a statement. "By protecting megafauna, we help maintain the dynamic balance of our seas, and ensure the entire ecosystem's resilience and natural productivity."
WWF-Philippines reports that megamouth 41's belly was full of shrimp larvae, which it caught and gobbled in its roughly 3.5-foot- (1-meter-) wide mouth. The shark is a sluggish swimmer and can end up being chum for other marine animals: Previous specimens have born scars of circular bites made by so-called cookie-cutter sharks, which are faster and more aggressive than these behemoths. Among the sightings catalogued by FLMNH: a megamouth shark being attacked by a sperm whale in 1998 off the coast of Indonesia.
To find out more about the mysterious shark, ScientificAmerican.com spoke with George Burgess, director of FLMNH's Florida Program for Shark Research.
[An edited transcript of the interview follows.]
What is a megamouth shark?
A megamouth shark is a member of the same order of sharks that includes white sharks, basking sharks and mako sharks. It's in its own family and its own genus as a single species (Megachasma pelagios), and it's in the Megachasmidae family. It's one of a kind, or monotypic, as we say in the scientific world. It's the only member of its group, the only member of its family, and the only member of its genus.
It was not discovered until 1976 in Hawaii. The specimen had gotten tangled up in what's called a sea anchor, which is basically a parachute that's put behind a boat on the open sea to keep the boat from drifting too fast. This is a species that basically eats small shrimp—the little krill in the water. It probably spends most of its time in at mid-depth but does come to the surface, mostly to chase the large masses of krill as they go up and down in the water column during their natural, daily migrations. It's pretty amazing that this animal, which gets reasonably large, was not discovered until the year that it was. Where it lives and the lack of sampling in that kind of an area probably have a lot to do with that. There's been a number of specimens found and, in fact, every year we're finding more and more, suggesting that this animal actually has been around, in terms of contact with humans, for quite some time now. It's just that there was a lack of recognition by the humans that what they had was something new at the time or unusual. Because this critter is seen or encountered oftentimes in Third World countries or in areas where there's less scientific presence, it's become pretty clear that it just simply wasn't recognized in the catches.
The most recent megamouth was caught in the Philippines. Is that the part of the world where they dwell?
Now that it is being recognized, we're getting quite a number of reports of them in certain places: Most of them are coming [in the Pacific,] from southern Japan to the Philippines and down to New Guinea. We're also hearing from people on the ground in those areas when these things are caught, through interviews, that oftentimes the fishers in the areas say, "Oh yeah, we've seen these things several times."