Basking sharks seen in Cornwall

The basking shark spotted in Pendeen (Image: Gareth Williams)

A Cornish fisherman has spotted basking sharks for the past two days while out on his boat.

Gareth Williams, aboard his family fishing boat, has photographed all the basking sharks and hopes to see some more. He says it’s the first time he has seen them for more than 10 years.

I fish off the north coast of Hayle and was on my boat out there yesterday in Pendeen. I always fish around that area but you rarely see basking sharks, and many people have said the same. I haven’t seen one in about 10 years, if not more. My dad has been a fisherman for 37 years and I don’t think he has seen one either for at least 12 years.

Gareth Williams – fisherman

Basking sharks are the second-largest living shark after the whale shark, and one of three plankton-eating shark species.

Despite their large size and threatening appearance, basking sharks are not aggressive and are harmless to humans.

Ten facts about basking sharks…

  1. They’re bus-sized filter feeders
    Basking sharks can grow to be 36 feet long and weigh four tons or more. They eat plankton, fish eggs, and other minuscule organisms.

2. People used to call them ‘sunfish’
Over the centuries, English-speakers have given these leviathans plenty of different names. In 1769, Welsh naturalist Thomas Pennant argued for ‘the basking shark’. Like most scientists at the time, Pennant believed that these huge fish hang around near the surface of the ocean in order to absorb solar rays. They really do this because plankton congregates just under the surface.

3. They can go airborne
The giant fish might not be man-eaters, but they can still be dangerous. Biologists aren’t sure why, but basking sharks occasionally launch themselves out of the water Free Willy–style and come crashing back down with tremendous force. Maybe they do this in order to impress the opposite sex. Or perhaps breaching the surface helps them get rid of lamprey eels and other parasites that latch onto their skin.

4. Their oil-rich livers keep them afloat
Sharks don’t possess swim bladders. Instead, many species have enlarged livers that are filled with helpful oils to give the sharks buoyancy. As a way to compensate for their immense body size, basking sharks have evolved huge, squalene-filled livers—without which they’d sink like rocks.

5. They were once thought to hibernate on the sea floor
In 1953, a pair of biologists suggested that the reason basking sharks seemed to disappear from northern European and American waters every winter was that they were swimming down to the ocean floor and hibernating. The idea spread like wildfire. “At this moment,” reads a 1962 New Scientist article, “there are probably great schools of these enormous fish quietly resting at the bottom of the sea.”

6. They reek
Basking sharks produce a mucus-based slime that covers their skin as an anti-parasite defence mechanism. In fact, the smell is so powerful that some fishermen claim they can even smell a fully submerged basking shark from a considerable distance.

7. Juveniles have hook-shaped snouts
Juveniles look markedly different from older specimens with long snouts that curve downward. When the animals mature, however, their snouts become straighter and, proportionately, a lot smaller. Such conspicuous differences between the age groups once led scientists to believe that adolescent and adult basking sharks represented two different species.

8. Despite their many similarities, basking sharks and whale sharks aren’t close relatives
Our oceans are home to more than 400 shark species. Scientists have divided these up into eight major groups. Basking sharks are classified as lamniformes, along with great whites, shortfin makos, and sandtiger sharks. On the other hand, anatomical and genetic data reveals that whale sharks belong to the orectolobiformes order, as do nurse sharks. Therefore, the filtration systems of Earth’s two biggest fish must have evolved independently—a phenomenon known as convergent evolution.

9. Basking shark corpses have been mistaken for dead sea monsters
An alleged sea serpent carcass that washed onto a beach near Scituate, Massachusetts in 1970 was positively identified by several experts as the rotting corpse of a basking shark. Over the past 200 years, many other so-called “sea monster” bodies have turned out to be probable basking sharks. Why does the same story keep repeating itself? Well, when the filter-feeders die, their lower jaws tend to break away from the rest of the body at an early stage in the decomposition process. The tail and dorsal fins are also among the first things to fall off. Consequently, a dead basking shark might look an awful lot like a long-necked, small-headed plesiosaur or maybe some kind of sea serpent.

10. Great whites and orcas may or may not be natural predators
Orcas and great whites have been seen feasting on dead basking sharks but it’s possible these predators were merely scavenging dead remains. No confirmed instance of either species attacking or killing the filter-feeders has been documented.

SOURCE 1, SOURCE 2

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