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International research uncovers the secret surfing life of refish hitchhiking on a blue whale

International research uncovers the secret surfing life of a refish hitchhiking on a blue whale

Re section on blue whale skin. Credit: Stanford University and Cascadia Research Group. Images collected under NMFS license #1


The reef fish (E family) and the super sucker on its head are the carcasses of sharks and other large marine creatures. However, a new study has now fully documented the behavior of “suckerfish” hitchhiking below the surface of the sea, and has discovered a more sophisticated skill set that can be used to navigate when trying to sail at an altitude of 100 feet. Powerful water power. Blue whale (Balaenoptera musculus).

Published on October 28th Journal of Experimental BiologyThe unique fluid environment research team of the Blue Whale in Palos Verdes, California and San Diego, composed of international researchers, reported that it used advanced biosensing tags and video recording technology to capture the first ever Continuously record the behavior of the host mor body. ability.

Studies have shown that the secret to the success of the re-fish successfully catching a whale that is 30 times larger to safely cross the ocean-they chose the best area on the whale’s body with the largest flow, such as the whale’s stomata, and the fish’s resistance increased by 84%. The team’s findings also show that even if the whale host’s impact speed reaches more than 5 meters per second, it is possible to use previously unknown surfing and predation behavior on special low-resistance traffic lanes to allow re-fish to move freely to eat and socialize. Exists near the surface of whales.

The researchers say that this study represents the highest-resolution whole-body fluid dynamics analysis of whales to date, and the insights derived from it may be used to better understand the behavior, energy use, and overall ecological health of the species. Basis, and in future research to improve the labeling and tracking of whales and other migratory animals.

“Whales are like their own floating island, basically like their own small ecosystem…. It is very exciting to understand the flow environment of blue whales in millimeter resolution through this research,” Assistant Professor of Biology Brooke Flammang (Brooke Flammang) said. At New Jersey Institute of Technology and the corresponding author of the study. “Through a lucky coincidence, our recording captured the interaction of re-fish in this environment and was able to use the unique flow dynamics of these whales to their advantage. This is incredible because we hardly understand re-fish. Behavior in its host. In the wild for any long time.”

So far, scientists studying the symbiotic relationship between re-fish and its host in its natural marine habitat have mainly relied on still images and anecdotal evidence, which makes it a mystery how they deal with their famous adhesion behavior under the water surface.

International research uncovers the secret surfing life of a refish hitchhiking on a blue whale

The mor fish feed and pass along the whale body. Image courtesy: Stanford University and the Cascadia Research Group. Images collected under NMFS license #16111.

In a recent investigation, the researchers used multi-sensor bio-recording tags with dual cameras, which were connected to the whale through four 2-inch suction cups. These tags can calculate various measurements inside the whale ecosystem, such as surface pressure and complex fluid forces around the whale, as well as GPS position and travel speed generated by tag vibration, while recording the recording fish at 24 frames per second and 720p Video. Resolution.

“Fortunately, the drag on the dimple-shaped aircraft cockpit has been measured many times, and we can use this knowledge to help find the drag caused by these repentances,” said the co-author of the Grove City Biofluid Dynamics Researcher. Erik Anderson (Erik Anderson) said. University and visiting researcher at the Woods Hole Oceanographic Institution. “But our research still needs to use computational fluid dynamics to calculate the flow of blue whales for the first time in history… This requires international biologists, programmers, engineers, and supercomputer teams to complete.”

Researchers at the Barcelona Supercomputing Center processed the team’s 211-minute video clips and whale tag data. A total of 27 re-fishes were captured in 61 positions of the whales and found that these mor fish were most often in the three most hydrodynamically favorable positions. Move between. The unique topographical features of whales cause the separation of water and wake: just behind the stomata, next to and behind the dorsal fin, and the lateral area above and behind the pectoral fin.

According to the research team’s measurements, Anderson said that when whales swim at a leisure speed of 1.5 m/s, the average-sized mor fish can experience as low as 0.02 Newtons after the wake, which is only half of the above free stream. resistance. However, Anderson pointed out that the average sucking power of the fish is 11-17 Newtons. Even the densest parking space on the whale’s tail, the shear force of the fish is about 0.14 Newton, which is far more than that. Although the force is greater, this is true even when riding a whale and swimming at a large speed.

Eric Anderson said: “We learned that Remora’s suction cups are so strong that they can be stuck anywhere, even the most resistant tail fl, but they all like to ride easily.” “This It saves them energy and reduces the cost of living because they hitchhiking and passing over whales like NASA probes on asteroids or certain asteroids.”

International research uncovers the secret surfing life of refish hitchhiking on a blue whale

The mor fish will skim it when it moves to a higher position on the whale. Stanford University and Cascadia Research Group. Images collected under NMFS license #16111.

Remolas goes surfing

The label shows that, in order to save energy, when walking on zooplankton, the fish uses the physical properties of the whale by surfing in a thin layer of fluid (called the boundary layer) around the whale’s body. The research team found that the resistance is reduced. Compared with the more powerful free video streaming above, it can be increased by up to 72%. Flammang said that these fish can be lifted within 1 cm from this layer of the host, foraging or mating with other low-resistance social places on the whale, occasionally changing direction by swiping over, or repeatedly attaching their suckers to the whale. Body and release.

Flammang suspects that the posterior mor can move freely without being completely peeled off by the fast host, which can be nearly seven times faster than the posterior mor through the Venturi effect.

Flammang explained: “This predation and surfing behavior is amazing for many reasons, especially because we believe that they are about one centimeter away from the whale’s body, thus taking advantage of the Venturi effect and using suction to keep them close. Contact.” “In the narrow space between the fish and the whale, when the fluid enters the narrow space, it moves at a higher speed but the pressure is lower, so it does not push the fish away, but can Attract it into the host. You can swim into a free stream to take a bite of food and then return to the boundary layer, but swimming in a free stream requires more energy.”

The team said that in addition to discovering new details of the fish’s free-riding skills, they will continue to explore the flow environment around whales and the mechanism for successfully attaching specially adapted organisms such as specifically fish to the host to improve animal tagging. Technology and expansion design. Behavior and ecological monitoring period. The team also used their new insights into the preferred low-resistance attachment locations of the new fish to better inform them of the possible location of the whales in future research.

Flammang said: “It is an extremely difficult process to study whales under the conditions of permission, research regulations and games of chance to find animals, and these tags usually fall off within 48 hours.” “If we can come up with a better one. The method of collecting long-term data through better label placement or better technology can indeed promote our understanding of this species and the many other animals that depend on it.”

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More information:
Flammang, BE, Marras, S., Anderson, EJ, Lehmkuhl, O., Mukherjee, A., Cade, DE, Beckert, M., Nadler, JH, Houzeaux, G., Vázquez, M., Amplo, HE, Calambokidis, J., Friedlaender, AS, Goldbogen, JA (2020). The mor fish choose where they stay on the blue whale. J. Exp.biology 223, jeb226654. DOI: 10.1242 / jeb.226654

Courtesy of New Jersey Institute of Technology

Citation: International research discovers the secret surfing life of blue whale hitchhikers (October 28, 2020), from https://phys.org/news/2020-10-international-uncovers-secret-surfing-life.html Retrieved to October 29, 2020

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