An interesting discovery concerning the behavior of blue sharks was carried out by a research group from the Woods Hole Oceanographic Institution (WHOI) and the Applied Physics Lab of the University of Washington (UW). According to the researchers, these fish use marine vortices, whirling currents that can be generated underwater, to descend into the corpuscular areas of the sea faster, almost accelerating, in order to feed and capture more prey.
In this oceanic layer, according to the researchers, located between 200 and 1000 meters deep, there is the largest fish biomass of any other marine area. The researchers came to this conclusion using locators attached to the body of a dozen blue sharks off the northeastern coast of the United States. The nine-month monitoring showed the scientists that blue sharks used sea vortices with a particular ability to sling hundreds of feet below the surface.
Here they also spent more than an hour looking for food basically composed of small fish or squid and then returning to the surface to warmer waters. Once heated the own body, they returned to accomplish this movement projecting in depth. These movements occurred mostly during the day, as specified by Camrin Braun, UW ocean ecologist and lead author of the study.
It is a behavior similar to that of white sharks that, unlike the blue sharks, are warm-blooded animals.
White sharks use a combination of hot and cold water eddies to dash into twilight areas while blue sharks, cold-blooded animals, rely exclusively on hot water vortices, as Braun explains: “Blue sharks they cannot regulate their body temperature internally to stay warmer than seawater like white sharks do. We think this is why they show a clear preference for hot water vortices – it removes a thermal constraint for deep dives.”