Rick Adrews, age 14, of Williamsport, Pennsylvania, for his question:
How big is the biggest fish?
Picture a streamlined monster about 45 feet long. Color him slaty gray and adorn his hide with pasty white polka dots. Add a spiky fin on his back and a pair of mighty fins to his tail. He is the whale shark ¬the largest of all fishes in the sea. If you care to weigh him, you may find that he tips the scales at around 20 tons.
When some people think of monsters of the deep, they assume that the biggest fish in the sea must be a great whale. Actually, the whales are air breathing mammals, which naturally disqualifies them from all fishy competitions. The largest fishes are not at all like the herrings and other average types. They belong in the Class Chondrichthes, a term meaning the cartilage fishes.
They are the sharks sea going monsters whose bones are made of gristly cartilage. Instead of scales, their tough hides are embedded with numerous small spikes. Instead of the ear muff shaped gill covers worn by most fishes, the sharks have slits, or gill clefts. Water enters the mouth and emerges through a double row of these clefts. where the neck should be.
The ancestors of the sharks prowled the salty seas ages before the bony fishes arrived. Their family tree dates back at least 350 million years. Scientists suspect that the early sharks were the first animals to have teeth. Remnants of these primitive teeth survive as small spiky scales, embedded all over the skin. Modern sharks are famous for their toothy jaws.
All the shark species are voracious meat eaters and some are deadly killers. Many are maneaters, lurking along the beaches of warm and tropical seas. Considering their shocking reputations, one would expect the largest shark to be a monstrous monster.
But, strange to say, this is not so. As the largest fish in the sea, the 45 foot whale shark is almost .a sissy. Divers report that he pays no attention when they swim around and around his 20 ton body. Neither does the gentle giant devour seals and large fishes, as his smaller relatives do.
Like all sharks, he is, of course, a meat eater. He also swallows his food alive and kicking. But his diet is limited to morsels such as sardines, shrimp and small squid. He swims through schools of these small creatures with his mouth open, gulping food with the sea water. The food is sifted out by a sieve of rakers in the back of his throat. He gulps it down and sends the surplus water out through his gill clefts.
Without a doubt, this whale of a shark is the biggest fish in the sea. Many specimens have been found to measure 45 feet. Some observers insist that a few have been known to measure 60 feet.
The female whale shark lays perhaps 16 eggs, sealed in crisp waterproof cases, and leaves them to hatch in the sea. Each egg case is an oblong column, about 12 inches long with sides about three and a half inches wide. Obviously this small object has a long way to go before it gets to be the biggest fish in the sea.