Previously, it was thought that white sharks were too large to enter densely populated seagrbad forests to hunt prey. Now, scientists who have attached cameras to a group of white sharks observed the opposite behavior: these mbadive predators are actually capable of maneuvering through these areas of tight seaweed to ambush seals.
A team of scientists, including Murdoch University doctoral student Oliver Jewell, attached cameras to eight sharks off the South African coast and observed images collected of giant animals. The team, which published its conclusions in Biology letters, discovered that sharks can traverse large fronds and stipes and navigate through dense forests of algae to pursue their prey. According to Jewell, this type of hunting behavior has not been captured before in the chamber.
Shark chambers capture large targets hunting algae for the first time. New investigation by @MurdochUniIt's Oli Jewell @JewellResearch In collaboration with @MontereyAq Y @Stanford https://t.co/DRdFg1Owfl pic.twitter.com/0lz4A2Ou9G
– MurdochUniNews (@MurdochUniNews) April 3, 2019
"The film we picked gives us a new perspective on this species. "We can see how they interact with their environment in real time, and they are able to make 180-degree turns in the algae forest," Jewell said in a press release from Murdoch University. "In the past we would have to guess. We would track the sharks to the edge of the algae forest but then we would lose the signal. "
To securely attach the cameras, the team had to attract white sharks to their boat. The team placed fish cut into small pieces (chum) and a seal in the water to attract them near the boat, so that they could use a device that resembled a fishing rod to gently hold a camera and a motion sensor in place. its dorsal fins. These special tags were created to stay in the sharks for a few hours, before they were detached and collected on the surface.
A great white shark swimming in the water. (Photo credit: Skeeze / Pixabay)
Jewell said the studio images show only a small part of the hunting behavior of a white shark. Many Cape fur seals were also seen swimming through the seaweed forest, which was located in the Dyer Island Marine Reserve. Newsweek reported that they exhibited predator evasion techniques, such as blowing bubbles and staying low on the seabed. The 28 hours of filming did not film deaths in the dense algae forest, however, seven sharks continued to move in thick areas of algae, while four sharks touched algae fronds. The study showed how these animals traveled differently to hunt or hide in these forests of tight algae.
The labels of the cameras, designed by the Monterey Bay Aquarium Research Institute (MBARI), could dive more than 1,500 meters into the water, and according to Dr. Salvador Jorgensen, co-author of the study and scientific researcher senior at Monterey Bay Aquarium, some of these camera tags used to observe white sharks served as test models for future camera tags.
"Actually, we are just scratching the surface with this study, there are many layers in their behavior. In the more than 15 years that we have been studying, it is clear that white sharks are very versatile, "said Dr. Jorgensen." They use very different habitats, from diving deep in the ocean of medium waters to bushwacking. "through the coastal algae forests".
He added: "More research of this nature is needed to help better understand the ocean resources used by this incredible species, so we can inform the administration and do more to ensure their survival."
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