Scientists discovered a walking shark that lives off the coral reefs along the coast of Halmahera, a remote Indonesian island. What readers may find even more amazing is that this is there are several other types of Indonesian walking sharks!
Epaulette sharks are named for the large black round mark that resembles a giant eye and is found behind the pectoral fin. They combine side-to-side wriggling with coordinated pectoral and pelvic fin movements to enable them to walk along the uneven rocky and coral reefs. Their fins can actually rotate almost 360 degrees which give them the ability to balance on any surface. The elongated slender body of epaulette sharks enables them to crawl through the cramped, meandering passageways within coral reefs as they search for food.
The shark is generally a brown color with clusters of dark spots helping it blend into the sand below. The new species, called Hemiscyllium halmahera, has a slow and awkward movement and depends on its coloring and “apparent large eye” to protect it from all the larger predators that live among the reefs.
“The wriggling gait of the Epaulette Shark has been studied as a model of the probable limb movements used by the first tetrapods (four-footed vertebrates) to clamber from the sea onto land,” according to the ReefQuest Centre for Shark Research. “This research provides evidence supporting the evolutionary theory that the paired limb movements necessary for terrestrial locomotion predate the first amphibians.”
The shark grows up to 27 inches long and is harmless to humans. Their diet consists of worms, shrimp, crabs, small fish and other small marine animals. The epaulette shark uses is short snout to snuffle through sandy patches rather like a determined pig searching for truffles. They often adopt a peculiar stance while searching over soft surfaces, with its body elevated on the paddle-like fins in a shark-like form of a push up.
Even more amazing is that epaulette sharks are able to survive in tide pools left behind during low tide. These shallow pools become extremely oxygen poor by the time the tide rises and once again the trapped animals can swim free. Epaulette sharks seem to maintain blood flow to the brain by selectively dilating blood vessels leading to it.
This allows them to walk for hours at a time among exposed tide pools full of rich feeding and effectively use the small amounts of oxygen these warms pools provide. Additionally their nerves seem to be adapted to function under low-oxygen conditions for prolonged periods of time.
Researchers are working to discover how the shark manages in hypoxic conditions. They hope it might provide new solutions for stroke patients or during heart surgeries. Scientists at the Monterey Bay Aquarium think they may also provide answers on how to help people who end up in low-oxygen conditions, such as drowning or heart attacks.
The discovery of the newly named shark highlights the plight of sharks in Indonesia, where they are heavily hunted for their meat, says Conservation International. For decades Indonesia led the world in the export of dried shark products. That is changing with the introduction of new initiatives to protect sharks.
In the last six months, for example, two of the country’s biggest tourist destinations, the island groups of Raja Ampat and West Manggarai, have outlawed shark and ray fishing in their waters. The Ministry of Marine Affairs and Fisheries is also drafting legislation to protect endangered sharks and rays, said Agus Dermawan, director of the Ministry’s Marine Conservation Directorate, in the release.
Part of the reason for the shift toward conservation is that sharks are important for tourism. Literally sharks are now worth more alive in the ocean than they are worth dead. Dermawan explained, “We now know, for instance, that a living manta ray is worth up to US $1.9 million to our economy over the course of its lifetime, compared to a value of only $40 to $200 for its meat and gill-rakers which are used in traditional medicines.