To me, it appears that the surfer dudes out there might as well forget worrying about Sharks - THIS is scary!!!
( as evidenced by the multitude of triple exclamation marks in this post!!!)
Blog about "The World's best Shark Dive" by Beqa Adventure Divers. Featuring up to eight regular species of Sharks and over 400 different species of fish, Shark diving doesn't get any better!
The attached video is of dolphins playing with silver colored rings which they have the ability to make under water to play with.
It isn't known how they learn this, or if it's an inbred ability. As if by magic the dolphin does a quick flip of its head and a silver ring appears in front of its pointed beak. The ring is a solid, donut shaped bubble about 2-ft across, yet it doesn't rise to the surface of the water! It stands upright in the water like a magic doorway to an unseen dimension. The dolphin then pulls a small silver donut from the larger one. Looking at the twisting ring for one last time a bite is taken from it, causing the small ring to collapse into a thousands of tiny bubbles which head upward towards the water's surface. After a few moments the dolphin creates another ring to play with. There also seems to be a separate mechanism for producing small rings, which a dolphin can accomplish by a quick flip of its head.
An explanation of how dolphins make these silver rings is that they are "air-core vortex rings". Invisible, spinning vortices in the water are generated from the tip of a dolphin's dorsal fin when it is moving rapidly and turning. When dolphins break the line, the ends are drawn together into a closed ring. The higher velocity fluid around the core of the vortex is at a lower pressure than the fluid circulating farther away. Air is injected into the rings via bubbles released from the dolphin's blowhole. The energy of the water vortex is enough to keep the bubbles from rising for a reasonably few seconds of play time. All this time we just thought the Dolphins were just swimming but it appears they were playing.
"The group is collecting information about the species to help the government of Canada to determine whether or not to list Basking Sharks as endangered off the coast of B.C (my emphasis).
After the sharks clashed with fishing equipment mid-century, the Federal Government embarked on a Basking Shark eradication program from the late 1940s until the 1960s. Blades were attached to the front of boats and driven through the gentle giants and since the 1990s, there have only been sporadic sightings of Basking Sharks on the West Coast of Vancouver Island.
Researchers previously scanned the waters on the West Coast in the spring and last fall and didn't come up with any sightings."