VOA慢速英语2021--小鲨鱼在温暖的海洋中艰难求生

Scientists say baby sharks are at risk of being born smaller and without the energy they need to survive because of warming oceans from climate change.

Scientists working with the New England Aquarium¹ in Boston, Massachusetts studied epaulette sharks, which live off Australia and New Guinea. They found that warmer conditions sped up the sharks' growing process. That meant the sharks were born earlier and very tired.

John Mandelman is vice² president and chief scientist of the Anderson Cabot Center for Ocean Life at the New England Aquarium. He said the findings could be used in the study of other sharks, including those that give birth to live young. The scientists published their findings in the journal Scientific Reports earlier this year.

Mandelman said it is widely believed that epaulette sharks are "hardy," or able to survive difficult conditions. "What it means is this very resilient species is more vulnerable than we thought, and this could be true of other sharks," he added.

The scientists studied 27 sharks using the New England Aquarium's reproduction program. Some were raised in average summer water temperatures, about 27 degrees Celsius³. Others were raised in higher temperatures around 29 degrees Celsius and 31 degrees Celsius.

They found that the sharks raised in the warmest temperatures weighed much less than those raised in average temperatures. They also showed reduced energy levels.

Epaulette sharks can grow to a length of about one meter. Their name comes from large spots on their bodies that look like decorations on some military clothing. The sharks are listed as stable and a species of "least concern" on the International Union for Conservation of Nature Red List of Threatened Species.

One study this year found that worldwide numbers of oceanic sharks and rays dropped more than 70 percent between 1970 and 2018. Overfishing is a main concern, while climate change and pollution also threaten sharks.

Carolyn Wheeler is a doctoral student at the University of Massachusetts Boston and with the ARC Centre of Excellence⁴ for Coral Reef Studies at James Cook University in Australia. She was the lead author of the epaulette shark study. She said that while all the sharks survived, those raised in warmer temperatures were not strong enough to survive for long in the wild.

She added that if the sharks are born smaller than usual "they are probably going to have to start looking for food sooner — and they're going to have less time to adjust to their surroundings."

Mariah Pfleger is an ocean scientist at the protection group Oceana. She said the study should serve as a warning to ocean governing agencies that careful supervision⁵ is needed to prevent the loss of more sharks.

"This study further exemplifies that sharks will not be immune to a warming ocean," Pfleger added.

Words in This Story

adjust – v. to change in order to work or do better in a new situation

decorations – n. a medals or awards given to someone for doing something brave or honorable such as fighting bravely in a war

exemplify – v. to be a very good example of something; to show something very clearly

immune – adj. not capable of being affected⁶ by a disease

resilient – adj. able to become strong, healthy, or successful again after something bad happens

species – n. a group of animals or plants that are similar and can produce young animals or plants

stable – adj. in a good state or condition that is not easily changed or likely to change

vulnerable – adj. easily hurt or harmed physically, mentally, or emotionally

1 aquarium   

n.水族馆，养鱼池，玻璃缸

参考例句：

• The first time I saw seals was in an aquarium.我第一次看见海豹是在水族馆里。
• I'm going to the aquarium with my parents this Sunday.这个星期天，我要和父母一起到水族馆去。

2 vice   

n.坏事；恶习；[pl.]台钳，老虎钳；adj.副的

参考例句：

• He guarded himself against vice.他避免染上坏习惯。
• They are sunk in the depth of vice.他们堕入了罪恶的深渊。

3 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

4 excellence   

n.优秀，杰出，(pl.)优点，美德

参考例句：

• His art has reached a high degree of excellence.他的艺术已达到炉火纯青的地步。
• My performance is far below excellence.我的表演离优秀还差得远呢。

5 supervision   

n.监督，管理

参考例句：

• The work was done under my supervision.这项工作是在我的监督之下完成的。
• The old man's will was executed under the personal supervision of the lawyer.老人的遗嘱是在律师的亲自监督下执行的。

6 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。