Researchers Discover New Pathway For Methane Production In The Oceans; 'A Harbinger Of Many New Insights'
Michigan Researchers Discover Caribou Hunting Structures Under The Surface Of Lake Huron
Surfer: Shark Punch Technique Learned from Discovery Channel's Shark Week; 'It’s Like Your Worst Nightmare'
Scientists Discover Astounding Deep-Sea Sponges With Carnivorous Ways, 'Jaws Of A Great White Shark'
Florida Shark Tournament Ends as 11 Killed, Over 300 Released; 765-pound Tiger Shark Biggest Catch
Scientists Discover New Bass Species In Florida; 'It Found Us'
Scientists Uncover Relationship Between Lavas Erupting On Sea Floor And Deep-Carbon Cycle
Research: Health Defects Found In Fish Exposed To Deepwater Horizon Oil Spill; Effect 'Can Take Time To Emerge'
NOAA: Sea Surface Temperatures Reach Highest Level In 150 Years On Northeast Continental Shelf; 'The Ecosystem Is Changing'
'Flipperbot' And Baby Sea Turtles Reveal Principles Of Motion In 'Complex, Yielding Substrates'
Texans Snare 'State Record' 880-pound, 14-foot Alligator With 'Secret Recipe Of Chicken And Some Other Stuff'
Guinness: India Park Home to World's Largest Crocodile; 23 Feet
750-lb Hammerhead Shark Caught Off Florida Coast May Be World Record
Strange Creature Found On Russian Coastline Baffles Locals
Freak! Malaysian Fisherman Reels in Shark with 'Webbed Feet'
Strange Creature Found On Russian Coastline Baffles Locals - 443 comments
Freak! Malaysian Fisherman Reels in Shark with 'Webbed Feet' - 380 comments
Shark Attack Leaves Florida Student Scarred, Wounded; 'There Was Blood' - 293 comments
Guinness: India Park Home to World's Largest Crocodile; 23 Feet - 274 comments
1063-pound, 12-foot 6-inch Mako Shark Hooked off Florida Coast May Be World Record - 264 comments
Tiger shark swimming with accelerometer attached to the dorsal fin. credit C.Meyer
Accelerometer attached to the dorsal fin of a tiger shark credit. credit C. Meyer
MāNOA, Hawaii -- In a joint research effort between the University of Hawaiʻi at Mānoa's Hawai'i Institute of Marine Biology (HIMB), University of Tokyo, the Japanese National Institute of Polar Research, and the University of Florida, scientists have shed new light on the hunting behavior of tiger sharks by studying their swimming dynamics off the west coast of Hawai'i Island.
Tiger sharks are cosmopolitan predators which consume a wide variety of prey, and have large home ranges, moving hundreds of kilometers between oceanic islands and far out into open ocean to fill their resource needs. Scientists equipped four tiger sharks with high-resolution accelerometers (devices that record swimming speed, depth, temperature and acceleration) and digital still cameras to obtain the most detailed view to date of tiger shark swimming behavior. These methods allowed researchers to determine what tiger sharks were doing during vertical movements.
Many open ocean fishes and sharks exhibit 'yo-yo' swimming patterns (repeatedly climbing and diving through the water while swimming), and scientists hypothesize this behavior might be linked to energy conservation, hunting or navigation. Previous studies showed tiger sharks also engage in yo-yo diving behavior but the reasons were unclear.
This new research links swimming events to capture of prey during vertical movements. The accelerometers revealed tiger sharks beat their tails almost continually as they moved up and down through the water, and rarely glided downwards, suggesting energy conservation is not the primary reason for yo-yo diving in this species. Camera images showed tiger sharks frequently encountering a variety of potential prey items such as reef and pelagic (deep-water) fishes, with prey fish observed in over 151 images from just one shark alone. One of the monitored sharks was shown to accelerate from the seabed towards a school of fish, and remained with this school for over 20 minutes. Bursts of swimming associated with other images of reef fishes indicate possible prey pursuit; one picture from the camera suggests the possible capture of a unicornfish.
"These findings are exciting because they have given us unprecedented new insights into the behavior of these huge and difficult to study marine predators," explains Dr. Carl Meyer, a researcher at HIMB and the lead U.S. scientist of the project. Meyer also emphasizes the importance of these results "although we have long debated the reasons for the yo-yo diving, we have only recently developed tools allowing us to directly measure the behavior in sufficient detail to understand what these animals are actually doing".
This research has shed new light on hunting behaviors by demonstrating that tiger shark yo-yo diving behavior is not primarily an energy conservation strategy, but a search strategy that effectively combs large three-dimensional spaces for prey.
Views expressed in this article do not necessarily reflect those of UnderwaterTimes.com, its staff or its advertisers.
Reader Comments
1 person has commented so far.In 1967 - 68 we hade three shark attacks to swimmers in the beaches nearby the Veracruz, harbour in very shallow water 4-5 feet. Unfortunally we did not have the actual technology, but we suspect were made by tiger sharks ("Tintoreras" local name ). I woudlike to know your opinion. Thanks.
comment# 1 - GONZALO ESTRADA FERNANDEZ DE LARA · Veracruz, méxico. · Jun 8, 2011 @ 3:42pm