OVERFISHING MAKES GREAT WHITE SHARKS ENDANGERED|人類濫捕.汙染 南非大白鯊銳減

Human activities and environmental change has put marine lives at risk. In South Africa, great white sharks are now endangered species. Also in Australia, many Green sea turtles have died while being treated or rescued after the storm and no-one really knows why. Michael Rutzen has been free diving with great white sharks for nearly 20 years. He noticed a sharp decline in numbers of the sharks in waters off the Western Cape of South Africa. ==MICHAEL RUTZEN, Great White Shark Expert== Through the years of me being at sea working with the sharks, I saw a rapid decline in the animals. At the moment, in 2012, there was between 350 and 522 animals left. Scientists say people pose more of a threat to great white sharks than the sharks pose to people. Overfishing, pollution and nets put their population at risk. As a top predator in the marine world, global great white sharks' population is estimated at 4,000 to 25,000, which is similar to the number of land predators such as tigers and African lions. ==SARA ANDREOTTI, Great White Shark Researcher== If great white sharks will be taken out of the environment, our Cape fur seal population is going to expand too much and that will have a negative effect on the fishery and the rest of the eco-system. Several experts see them heading toward extinction, while others believe rising seal populations are a signal of more sharks. However there is no denying that great white sharks should be protected. In Queensland of Australia, a world-first research center is on a quest to stop turtles dying early. ==ELLEN ARIEL, Associate Professor, James Cook University== It's very difficult to diagnose why an animal is sick if you don't know what it looks like when it's really healthy. So what we're looking at here is healthy animals, what constitutes a healthy turtle. Scientists study Australian Green sea turtles under controlled conditions to understand why many turtles have died while being treated or rescued after storms. It's a mystery with few clues so far, and the scientists hope to find the answer and save more lives on the Great Barrier Reef. TRANSLATED BY：SASHA CHIU