VOA慢速英语2021--美国西海岸棱皮海龟数量大幅下降

Major Drop in Leatherback Sea Turtle Population off US West Coast

Scientists say there has been a major drop in the population of leatherback sea turtles off the U.S. West Coast.

Researchers say there was an 80 percent drop in one group of leatherbacks found off the California coast over the past 30 years. One recent study found a 5.6 percent yearly decrease in the population.

Leatherbacks are massive sea turtles dating back to the time of the dinosaurs¹. The animals can grow up to 1.5 meters in length and weigh as much as 680 kilograms.

The leatherback sea turtles found along the U.S. Pacific coast are actually born thousands of kilometers away, on beaches in Indonesia, Papua New Guinea, Vanuatu and the Solomon Islands. The animals migrate 11,000 kilometers across the Pacific Ocean to feed on jellyfish in waters off the U.S. West Coast. Then, they swim back.

As many as 60 percent of the leatherback turtles born in the western Pacific Ocean are believed to make the trip to California. Scientists are not sure why some do and others do not. Some go farther north, to waters off Oregon or Washington state.

Scott Benson is an ecologist with the U.S. National Oceanic and Atmospheric² Administration's (NOAA) fisheries service in Monterey, California. He has studied the turtles for many years and recently co-wrote a study on leatherback populations. Benson told The Associated Press that the long trip across the Pacific demonstrates the strength of the sea turtles.

"There are birds that go farther, but they fly. There's a whale shark that might swim a little further, but it doesn't have to come up for air," he said. The leatherbacks, he noted³, are "actually pushing water all the way across the Pacific Ocean."

Now, just as scientists are beginning to fully⁴ understand these unusual creatures, the turtles are quickly disappearing. Similar population decreases have also been documented at beaches where leatherbacks nest on the western Pacific.

Scientists say that if nothing changes, the leatherbacks could completely disappear from the U.S. West Coast within 30 years. The population drops are mainly blamed on international fishing activities, the destruction of nesting grounds and climate change.

"The turtles were there and we finally started paying attention," said Jim Harvey, director of San Jose State University's Moss⁵ Landing Marine⁶ Laboratories. He was a co-writer of the new study. "We got into looking at the story just as the story was ending," Harvey told the AP.

The study provides important information, but also shows the threats the leatherbacks face, said Daniel Pauly, a fisheries professor at the University of British Columbia in Canada. Pauly, who was not involved in the study, is an international expert on the effects of fishing on ocean ecosystems⁸.

The animals can be killed when they get trapped in fishing equipment. Scientists say the population is also harmed because a lot of turtle eggs are removed from beaches.

Researchers say that while all the world's leatherbacks are under pressure, the group that migrates for months across the Pacific faces the greatest threats.

"If you find the decline in one place, that might have a number of causes, but if you find the same estimate of decline in two places that is something much more serious," Pauly said. He added that the sea turtles "are really in big trouble."

NOAA launched an aggressive plan to save leatherbacks in 2015 and is set to release a new action plan this month. The plan is meant to persuade governments and international organizations to join efforts to save the turtles.

Benson, the NOAA ecologist, said there is still time to stop the decrease, but that it will require an immediate⁹, international effort. "If nothing is done to reverse this course, this population will become ... extinct in the Pacific Ocean."

Words in This Story

nest – v. to live in a nest (a home built by animals where they can lay eggs and live)

ecosystem⁷ – n. everything that exists in a particular environment

decline – n. a situation in which something becomes less in amount, importance, quality or strength

reverse – v. to change a situation or the order of things so that it becomes the opposite

extinct – adj. when something (such as a plant or animal species) has died out completely

1 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》

2 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

3 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

4 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

5 moss   

n.苔，藓，地衣

参考例句：

• Moss grows on a rock.苔藓生在石头上。
• He was found asleep on a pillow of leaves and moss.有人看见他枕着树叶和苔藓睡着了。

6 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

7 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

8 ecosystems   

n.生态系统( ecosystem的名词复数 )

参考例句：

• There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
• Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样，从雨林到半荒漠等不一而足。 来自辞典例句

9 immediate   

adj.立即的；直接的，最接近的；紧靠的

参考例句：

• His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
• We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。