2014.10.11雅思考试阅读考题回顾

Coral reef fish are fish which live amongst or in close relation to coral reefs. Coral reefs form complex ecosystems with tremendous biodiversity. Among the myriad inhabitants, the fish stand out as particularly colorful and interesting to watch. Hundreds of species can exist in a small area of a healthy reef, many of them hidden or well camouflaged. Reef fish have developed many ingenious specializations adapted to survival on the reefs.

Coral reefs occupy less than one percent of the surface area of the world oceans, but still they provide a home for 25 percent of all marine fish species. Reef habitats are a sharp contrast to the open water habitats that make up the other 99% of the world oceans.

However, loss and degradation of coral reef habitat, increasing pollution, and overfishing including the use of destructive fishing practices, are threatening the survival of the coral reefs and the associated reef fish.

As an example of the adaptations made by reef fish, the yellow tang is a herbivore which feeds on benthic turf algae. They also provide cleaner services to marine turtles, by removing algal growth from their shells. They do not tolerate other fish with the same color or shape. When alarmed, the usually placid yellow tang can erect spines in its tail and slash at its opponent with rapid sideways movements.