سؤال قراءة ستيب محلول — الفكرة الرئيسية (تدريب 6666)

(1) In 1950, about 1.7 million fishing vessels of all shapes and sizes plied the world’s oceans, but just 20 percent of them had motors, limiting their range and the amount of fish they could collect. Now, 65 years later, the number of boats has jumped to 3.7 million fishing vessels, 68 percent of which are motorized in some form, an increase that is putting more and more pressure on the world’s oceans. (2) The boom in fishing vessels doesn’t mean there’s plenty of fish in the sea. In fact, it’s quite the opposite. To understand the health of fisheries, ecologists calculate “catch per unit of effort (CPUE)” or the amount of effort and resources it takes to catch a fish. Fishing boats today only catch about 20 percent of the fish for the same amount of effort as boats in 1950. (3) The increase in fishing vessels, however, did not happen evenly across the globe. While fish stocks in most of North America, Europe and Australia have stabilized in recent decades due to more stringent regulations, that’s not the case in much of the rest of the world. Fleets in Asia, for example, have increased by 400 percent over the same time period. And the number of fishing boats hitting the water won’t decrease anytime soon-the study estimates that by 2050, another 1 million fishing boats will be chasing fish. (4) And there’s not that much left to go around. According to the United Nations Conference on Trade and Development, 90 percent of the world’s fish stocks are either currently overused or completely exhausted. What does the passage conclude about the world’s fish stock?