Drone Captures Tiger Shark Feeding Frenzy
A drone has captured a bloody feeding frenzy by around 70 tiger sharks on a dead whale, turning the waters of Shark Bay in Australia red.
A drone has captured a bloody feeding frenzy by around 70 tiger sharks on a dead whale, turning the pristine waters of the aptly named Shark Bay in Australia red.
Two boatloads of tourists were on a cruise to Dirk Hartog Island in Western Australia when they came across the gruesome spectacle on Friday.
Geraldton-based Eco Abrolhos Cruises sent up a drone to record nature taking its course. The footage showed the sharks ripping the giant humpback whale carcass to shreds, leaving a trail of crimson water.
"Something to show and tell the grandchildren," the company said on its Facebook page after posting the footage, which had been viewed nearly a half-million times by Monday.
Passenger Leesa Franks said on the social media site: "We liked, liked, liked. Awesome day yesterday, thanks so much."
Shark Bay is a World Heritage-listed area some 800 kilometres (500 miles) north of Perth. It is known for its large marine animals including whales, sharks, dolphins, dugongs and turtles.
The world’s No. 1 place for sharks has just been identified -- off the coast of Darwin Island and Wolf Island in the northern portion of the Galápagos archipelago. The waters of these Pacific islands contain the largest shark biomass ever reported, about 13 tons for every 2 1/2 acres. The findings are published in the journal Peer J. “The more sharks, the greater the biomass. And the larger the sharks, also the greater the biomass,” said lead author Pelayo Salinas de León, of the Charles Darwin Research Station (CDRS). In this gallery, see how conservation efforts are working at the famous Pacific archipelago.
The natural rock formation called “Darwin’s Arch,” named after the British naturalist who spent so much time in the Galápagos Islands, protrudes from the water southeast of Darwin Island. The region is packed with multiple species of sharks and other marine life, the new study determined. The findings come after Ecuador designated the area a marine sanctuary in March 2016.
Salinas de León and his team of divers surveyed marine life in the area, where at least 33 species of sharks are found. The team most often found hammerheads, Galápagos, silky, black tip, whale, white tip and tiger sharks, he said. Other surveys found that waters within Costa Rica’s Cocos Island National Park, as well as within the Chagos Marine Reserve in the Indian Ocean, have the next largest shark biomasses.
Worldwide, overfishing has reduced the biomass of most sharks and other large predatory fishes by more than 90 percent -- even in remote areas -- which makes the new findings all the more remarkable. “Charles Darwin made the Galápagos Islands famous, but for the underwater world to be so full of life is something he probably never imagined,” said Enric Sala, National Geographic Society explorer-in-residence and leader of the Society’s Pristine Seas project. In December 2015, the Pristine Seas team of international scientists and filmmakers conducted the expedition in collaboration with the Galápagos National Park and CDRS.
Estimates by mass are important, as this enormous whale shark demonstrates. Several smaller sharks could fit into the same space taken up by this one. Until the recent establishment of the marine sanctuary, the northern Galápagos Islands region was not fully protected from fishing. There were some prior fishing restrictions, created in the late 1990s, which allowed marine life to recover somewhat from earlier depletions, but conservationists deemed them insufficient. Now, it can truly be said that sharks rule the waters there.
Like an opening scene from a James Bond movie, a school of fish parts ways to form a circle around a savvy predator -- in this case is a sea lion. Sharks feast on sea lions that feast on fish, including sometimes smaller sharks, demonstrating the region’s healthy food chain. “The isolated oceanic islands of this region provide productive feeding areas and also cleaner fish services," Salinas de León said. Like a car wash for sharks, certain fish like to eat dead skin, parasites and other unwanted things off of sharks. The sharks will often patiently wait while the cleaner fish do their work.
As the Pristine Seas divers rose from the depths around Wolf Island and paused to let the compressed nitrogen slowly dissolve in their bloodstream, a pod of bottlenose dolphins came to visit. Studies of beached whales and other marine mammals suggest that even these natural divers can suffer decompression sickness, or the bends, if they rise too quickly from too great a depth.
Juvenile snappers find protection from predators among the densely woven roots of mangroves at Fernandina Island, which is the third largest island in the Galápagos archipelago. (Isabela is the largest, followed by Santa Cruz.) As adults, the roles of these fish will change, and they'll be the ones hunting for smaller species in the same environment. Change is also constant for the sharks. Hammerheads, for example, move between oceanic islands in the tropical Eastern Pacific, Malpelo in Colombia or Cocos in Costa Rica. “During February through March, we believe that the large schools of female hammerheads frequently encountered around Darwin and Wolf Islands migrate to give birth to their young in mangrove areas of Colombia, Costa Rica and Panama,” Salinas de León said.
Being cold-blooded reptiles, marine iguanas must return to the surface not only to breathe, but also to warm up and gain the energy to maintain body functions. Before and after their midday diving, they lie in the sun on the sun-warmed rocks of the Galápagos Islands, absorbing heat from above and below. Sharks are known to eat the iguanas, so these reptiles can rest a bit easier while on land.
The researchers hope that the new Galápagos Marine Reserve will lead to international protections, especially because these predators move in and out of the region so much. Such protections are good for humans as well as sharks. As the scientists pointed out, a live shark is worth $360,000 to the Galápagos dive industry. “This value is obtained by dividing the total revenue from shark-based tourism per year by the average number of sharks sighted in a single dive in the Galápagos,” de León explained. The dollar value of a shark killed for its fins and meat is conversely worth only around $200 in mainland Ecuador markets. To conservationists and shark fanciers, however, the value of these apex predators -- as well as their favored top spot in the Galápagos -- is priceless.