When I am called upon to speak about sharks and shark conservation, I often mention how many different species of shark there are. People initially think of the larger, more iconic species, but there are approximately 360+ and the plus sign at the end of that number keeps growing seemingly every day.
The San Francisco-based California Academy of Sciences recently completed an expedition into the deep depths off Mozambique and came up with 4 new species of shark along with a long list of new invertebrates, fish, plants, and other marine critters. Mozambique lies along the southeastern coast of Africa, with the island of Madagascar to the east. The researchers were trawling along deep canyons in depths ranging from 1,500 feet to 3,000 feet deep.
This past summer, the academy conducted a marine biodiversity expedition off the Philippines and came across deep water species of swell shark. These are small sharks that are able to gulp seawater to expand or "swell" which either makes them look more menacing to potential predators or enables them to wedge themselves in rocky crevices for protection. At home in California waters, I have come across our local swell shark species and, if gently trying to coax them out into the open for a better look, have seen them swell up. At that point they're safe from curious divers as it would take a crowbar and a couple of sticks of dynamite to dislodge them (certainly not something I advocate).
Back in Mozambique, the Academy researchers also came across two new species of lantern shark which are capable of producing light at various points on their bodies in the dark depths. Scientists suspect that light-emitting sea creatures utilize this bioluminescent ability to both attract members of their own species and provide camouflage from predators. (Where the lights are placed can confuse a predator in thinking a tail is where a head should be, so their prey zigs when they thought it would zag.) Sadly, one of the lantern shark specimens was identified in a Taiwan fish market which means that commercial fisherman are dropping nets deeper and deeper in search of fish to fill their holds.
Another new shark discovered was a type of angel shark, basically a bottom dweller with wide pectoral fins that give the angel shark a very stingray or guitarfish-like appearance. The angel sharks coloration allows it to blend in with the bottom, much like other bottom-dwelling ambush predators including flounder and halibut. When I first began diving - meaning when I was young and dumb - I used to come across angel sharks at the base of Ship Rock off Southern California's Catalina Island. I would approach these sharks strewned across the bottom and slowly lift their tails just to see them suddenly dash off. But everything once in a while, one would turn around and race towards me, obviously annoyed and looking for trouble. Told ya' - young and dumb.
The California Academy of Sciences' most unusual find was an African dwarf sawshark or sawfish, brought up from around 1,600 feet. Though considerably smaller than most species of sawshark, this particular shark uses its "saw" or rostrum in much the same way as its larger cousins. Whipping it quickly from side to side, the shark stuns and wounds smaller fish, enabling it to easily feed on the wounded fish.
At the Aquarium of the Pacific in Long Beach, California, they have had a large sawshark on display in their Shark Lagoon exhibit for many years. It coexists with larger sand tiger sharks and rays, but every once in a while a curious smaller shark, like a blacktip reef shark, will forget his or her place, crowd the sawshark and get a little taste of sawshark hospitality. I've had the opportunity to film the Aquarium's saw shark and document their staff giving a blacktip shark a stitch or two. No great harm done and believe me, the blacktips learn fast.
The more research that takes place, the more it brings new species to light (This one expedition to Mozambique produced 33 scientific papers alone). In fact, David Ebert, a research associate at the Academy, said that about 200 new sharks and rays have been discovered in just the past decade, whereas close to the same number were identified in the previous three decades combined. So much for the idea of 360 species of sharks. I'll need to amend my notes. . .
Today, using submersibles and ROVs (remotely operated vehicles), scientists are finding more and more unusual creatures that have evolved and adapted to the harsh living conditions found in deep water. However, as remote and seemingly isolated as these animals may appear to be, they and the marine environment they call home are very much connected to the swallower waters that we may be more familiar with. It's one ocean and one incredibly complex, interwoven environment.
"A lot of [shark] species are going under the radar because they're not as high profile,"said David Ebert, referring to well-known sharks like the great white. "There's a lot out there in the big ocean we don't know anything about."
Source: National Geographic Daily News
Source: Deeper Blue
Source: Live Science