(HOST) Sharks are generally considered to be ill-tempered creatures, but commentator Ruth Page says there’s one that has a comparatively sunny disposition.
(PAGE) People who have swum with dolphins love the adventure, and are often impressed by the intelligent animals’ judgement.
I wonder how those swimmers would like to try swimming with the biggest fish in the ocean. Not as big as whales, of course – but Moby-Dick was no fish; he was a mammal. Some swimmers do this, you know. Luckily the gigantic whaleshark fish is called “the gentle giant.”
Pictures of the gigantic whaleshark, a true fish, are not uncommon, but the sharks haven’t been studied as thoroughly as have most of the world’s enormous creatures. That’s beginning to change. Recently, Natural History magazine ran a story by Steven G. Wilson, who went on an expedition to tag the twenty-five to forty-foot-long fishes, so scientists could begin to understand their lifestyles. How far do they swim? How deeply do they dive?
They eat by swimming along with their huge mouths open and consume whatever krill or small fish swim in. Like some of the whales, they have gill plates that filter out the nutrients and expel the water.
Wilson, swimming off a western reef in Australia, met a mere twenty-five-foot long shark and was getting a tag on it when a thirty-five-footer came up from behind, jolted into him, and whirled him through the water. He was in the way off the big visitor, who probably barely noticed him. It meant him no harm, though it gave him a free and somewhat scary ride. Unhurt, Wilson swam back to the boat and soon continued his investigations.
Snorkelers swim near whale sharks, which are attractive because of their gentle dispositions and because they often swim near the surface. Unfortunately, that makes them attractive to fishermen and invites frequent collisions with ships – not healthy for either the fish or the ship.
They need further study. No one knows how they interact with each other, how they mate, how long the gestation period is, how often the females give birth. None of these, or any other social interactions, have been seen. In 1995, a single female was harpooned and was found to have three hundred and one embryos inside her at various levels of development. Scientists realized the eggs hatch inside the mother, and babies aren’t born until they’re two feet long – not much for a mom who could be anywhere up to forty feet.
The sharks are rather pretty, with bluish skin covered with dots of white as if an artist had splattered paint on them in special patterns. As with so many of the earth’s treasures, now that people have really noticed the fish they are being over-fished: fish are smaller than they used to be, and catches have declined. Scientists and others who want to protect earth’s unusual treasures hope to find ways to protect them.
Ruth Page has been following environmental issues for twenty years. She is a long time Vermont resident and currently lives in Shelburne.