There have been several shark attacks on our bait or catches while we are fishing for yellowfin tuna off the coast of our island, Fuvahmulah. When our fishing guide and experienced fisherman Ahamadhukalo sees a yellowfin tuna on the line, he always tells us to pull the line as fast as we can to avoid tiger shark attacks that would mean losing our catch.
I can still vividly recall the time when I let go of a fishing line that was rigged with three lures. Every single lure was caught by yellowfin tuna. The fishing line, as resilient as steel, resisted any movement toward me. I yelled, and Ahamadhukalo and Obei, my friend, arrived to rescue me. I tugged on the fishing line. All three of the yellowfin tuna, though, were sliced properly. Sadly, all we managed to get was the fish’s head. On top of that, a massive tiger shark surfaced and slammed against the vessel’s underbelly, nearly sending Ahamadhukalo, who was on deck, plunging into the water below. Tiger sharks swam around the bokkoraa, a traditional tiny fishing vessel, while we removed the chopped fish head.
The sharks’ lightning-fast attacks on the yellowfin tuna we catch always baffle me. Maybe they’re in close proximity to the fish or school of fish that we’re attempting to reel in. I considered conducting some preliminary study on how these huge predators hunt in the deep. I learned some interesting things.
Researchers in Hawaii studied the feeding behavior of tiger sharks by examining their swimming patterns. The study was done in 2011 by the University of Florida, the University of Tokyo, the Japanese National Institute of Polar Research, and the Hawaiʻi Institute of Marine Biology (HIMB) at the University of Hawaiʻi at Mānoa. The study was done near Hawaii Island’s west coast.
Scientists fitted four tiger sharks with high-resolution accelerometers. These are devices that record swimming speed, depth, temperature, and motion. They also employed digital still cameras to study swimming behavior.
The study discovered that tiger sharks thrashed their tails almost constantly as they traveled up and down through the water, rarely gliding downward.
“These results are exciting because they have given us new information about how these huge, hard-to-study marine predators behave that we didn’t have before,” says Dr. Carl Meyer, a researcher at HIMB and the project’s lead U.S. scientist.
Many ocean fish, including sharks, adopt a hunting tactic that involves frequently climbing and diving through the water while swimming. This style of swimming is called “yo-yo” swimming. Experts previously believed that tiger sharks were engaging in this behavior to conserve energy, hunt, or navigate. However, this investigation demonstrated that there is no correlation between yo-yo swimming and energy conservation, foraging, or navigation.
Tiger sharks have an impressive ability to go for weeks without food. Their hunting strategy is centered around ambushing and stealth, not speed and strength. Thanks to their excellent camouflage, they may approach their victim stealthily and strike. When their prey is close enough, tiger sharks can unleash brief bursts of speed. Tiger sharks tend to back off if their food runs away, as if they don’t want to waste their energy on a fast chase.
A 2019 study undertaken by the Australian Institute of Marine Science, Murdoch University, the University of Western Australia, and Stanford University in California discovered that tiger sharks are complacent and lethargic predators.
Scientists placed specialty tags on 27 tiger sharks in the Ningaloo Reef off the coast of Western Australia, combining cameras with motion and environmental sensors.
“Our tagged sharks just continued on their courses without attempting to predate on the alert individual even if they were right in front of them,” said Dr. Andrzejaczek, a lead author on a research paper released about this study. “We found the sharks were more likely to use stealth to sneak up on their prey.”
Dr. Gleiss said, “They don’t waste energy following prey that knows they’re there and can easily get away.” “By sneaking up on turtles and big fish that aren’t paying attention, these sharks reduce the amount of energy they use and their chances of success.”
Tiger sharks are known for their infrequent rapid chases for prey and their lack of attacks on objects they carefully examine. When they find food, they don’t always chase it. Although they have excellent swimming abilities, they have limited agility, making a successful attack unlikely once identified. Tiger sharks use the stalking and attacking method to catch prey (Heithaus, Dill, Marshal, & Buhleier, 2001).
