![]() “The interactions made my mind race with a whole bunch of questions,” Lester says. Lester and her colleagues wonder if the Ningaloo whale sharks may be leaning on their agile neighbors to do some of the heavy lifting. Feasting beside the dappled giants in Cannon’s footage were other large fish such as tuna, trevally, and whaler sharks, as well as a divebombing cohort of wedge-tailed shearwaters, seabirds in the petrel family. Situated 750 miles north of Perth, the protected UNESCO world heritage site is home to relatively intact predator populations. Ningaloo Reef is renowned for its biodiverse waters. ( Learn more: Whale sharks may live up to a century, Cold War bomb dating reveals.) Both of these tactics require more effort than swimming slowly along, mouth agape, which makes it imperative to land a calorie-dense gulp when foraging this way. The whale sharks in the Ningaloo footage were seen ram feeding–charging at speed through the center of the bait ball-as well as positioning themselves vertically beneath it, primed to hoover fish into their mouths. When you’re longer and heavier than a school bus, eating is all about conserving energy. Each new piece of footage holds unique clues about what drives whale sharks to the bait ball table, and which strategies they use to make the most of it once they get there. But underwater photographic evidence like this is rare. Eyewitness reports of such events in Western Australia, for example, go back more than 20 years. Anecdotal evidence of the behavior has been documented at aggregations throughout the world’s tropical oceans. It’s likely that whale shark bait ball feeding occurs more frequently than it’s caught on camera. Even then, notes Lester, happening upon a feeding event like this is akin to finding a needle in an ocean-sized haystack. Whale shark meetups like the one at Ningaloo-which occurs each year between March and August-offer a unique opportunity for scientists and ocean enthusiasts to observe these elusive animals in shallow, nearshore waters. Not only can the behemoths swim across entire oceans, they’re also known to dive thousands of feet beneath the surface. “Whale sharks can be really challenging to study despite their huge size because they’re so mobile,” says Lester. Pinning down the specifics of when, where, and why these animals opt for more sizable sustenance, however, is a difficult task. While krill and other plankton make up the bulk of whale sharks’ diets, scientists have long known that small fish like anchovies and sardines-and even the occasional squid-do appear on the menu. They are currently listed as a vulnerable species however, they continue to be hunted in parts of Asia, such as the Philippines.This video captured at Western Australia’s Ningaloo Reef in March 2020 shows a group of whale sharks feeding on bait balls of fish in tandem with other predators, including tuna, whaler sharks, and dive-bombing birds called wedge-tailed shearwaters. The coral spawning of the area's Ningaloo Reef provides the whale shark with an abundant supply of plankton.Īlthough massive, whale sharks are docile fish and sometimes allow swimmers to hitch a ride. They are known to migrate every spring to the continental shelf of the central west coast of Australia. Preferring warm waters, whale sharks populate all tropical seas. Its two dorsal fins are set rearward on its body, which ends in a large dual-lobbed caudal fin (or tail). Its back and sides are gray to brown with white spots among pale vertical and horizontal stripes, and its belly is white. The whale shark's flattened head sports a blunt snout above its mouth with short barbels protruding from its nostrils. The mechanism is theorized to be a technique called “cross-flow filtration,” similar to some bony fish and baleen whales. In order to eat, the beast juts out its formidably sized jaws and passively filters everything in its path. The whale shark, like the world's second largest fish, the basking shark, is a filter feeder. ![]() They scoop these tiny plants and animals up, along with any small fish that happen to be around, with their colossal gaping mouths while swimming close to the water's surface. Fortunately for most sea-dwellers-and us!-their favorite meal is plankton. As the largest fish in the sea, reaching lengths of 40 feet or more, whale sharks have an enormous menu from which to choose.
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