I saw a fine example of this scenario near St Ives in Cornwall a few years ago. A group of jack-the-lads were splashing around in the shallow water, doing handstands, standing on each other's shoulders and generally frightening small children. Out of nowhere, a enormous shark appeared, and cruised along the beach towards them as if it had marked out one of their number for lunch.
They moved faster than a cartoon cat being chased by a giant dog. The shark just continued cruising along the beach and disappeared round a headland, while the teenagers regained their bravado and boasted about how they would have saved each other if the shark had attacked. Pretty unlikely, though. It was a harmless basking shark, a plankton feeder which would have a job gulping down anything larger than an undersized shrimp.
Still, the very presence of sharks, of any size, causes greater panic than King Kong window-shopping in Oxford Street. Thresher sharks, which have a very small mouth and feed mostly on mackerel, cleared south-coast beaches a few years ago when they followed mackerel shoals into shallow water. Even tiny blackfin sharks a few feet long keep people out of the water on tropical beaches.
There is something about that triangular dorsal cutting through the water that brings out our primeval fears. Australian researchers, testing people on reaction to words, tried snake, death, rape, murder and so on. But the winning word, the one that really sent the electrodes humming, was "shark".
Maybe, however, it should be the other way round, and sharks should be swimming for their lives when they sense humans. According to Traffic, a Cambridge-based wildlife monitoring group, sharks are increasingly endangered by mankind. Several species have been added to the "red list" of endangered species - including the basking shark.
Even Gavin Maxwell, the otter-loving author of Ring of Bright Water, saw nothing wrong with basking- shark murder. He set up a business off Scotland to kill them for the large quantities of oil in their livers.
The business went bust, but this has not prevented other fishermen from carrying out the same trade in the Irish Sea today.
Anglers are not blameless. The Shark Club of Great Britain encourages anglers to return them but still allows far too many immature blue sharks to be killed for a macho dockside picture. Some years ago, dead sharks were dumped in the sea or used as crab-pot bait. Now, they are sold to the French, who have a penchant for blue shark.
In more exotic places, shark catches play an important part in feeding local people, and that is fair enough. Less acceptable is catching a shark, cutting out the jaws as a gruesome trophy, and dumping the rest.
But shark-fishing is undeniably exciting. Off Scotland big porbeagle sharks, weighing more than 500lb, can be caught right through the winter. The Big Game Club of Scotland (0191-258 0668) is specifically targeting these, and letting them go afterwards - whatever it may do to the tourist trade.Reuse content