【明報專訊】Zebra sharks (豹紋鯊) have an unusual body shape— with a round snout and beady eyes, they look like a torpedo (魚雷) with a long tail. When young, they have white or yellowish stripes across their dark body, hence their name. As they grow up, the pattern changes to small dark spots against a greyish-brown body, which is why adult zebra sharks are sometimes also called leopard sharks. A full-grown zebra shark measures around 3.5 metres long, equivalent to two adult men.

Lazy bottom dwellers

Zebra sharks are found around coral and rocky reefs of inshore waters in the Indian Ocean and western Pacific Ocean. During the day, these sharks rest peacefully on the seafloor or move in a relaxed way, with their mouth open to breathe by pumping water across their gills. They only become active at night. The flexible and slender body of zebra sharks allows them to squeeze into cracks and crevices searching for food such as clams, crabs, small fishes and shrimps. After sucking up prey through their small mouth, they can grasp the prey and crunch tough shells using their strong jaws and multiple rows of teeth.

Not all eggs are oval

Zebra sharks breed by laying eggs. However, these eggs are nothing like those we see in daily life! While the eggshell of birds feel hard, the egg cases of sharks are leathery. Those of zebra sharks are dark brown or purplish black, looking more flattened and measuring about 20 cm long. There are fine, hair-like fibres covering the cases, which may help attach the eggs to rocks or corals at the seafloor. When they hatch, one side of the cases would split open and mini sharks would come out.

Be wise, responsible seafood lovers

As zebra sharks like staying in inshore waters, they are under the threat of overfishing and coastal development that pollutes and destroys their habitats. They are often victims of fishing for their fins, flesh, liver oil and cartilage. What may we do to conserve zebra sharks? The first thing is of course to say no to shark fin soup and other shark-based products. We should also choose sustainable seafood with reference to the Sustainable Seafood Guide, and certification from the Marine Stewardship Council.

Text and photos: Ocean Park Hong Kong

■Glossary

equivalent (adj) 相等的

dweller (n) 居住者

slender (adj) 纖細的

split (v) 裂開

[Smarties' Power English 第227期]