阅读理解We usually think fish can't talk. But there are a lot of sounds under the ocean. In fact, scientists believe that all sea animals – at least 250,000 kinds – can "speak"! If we stay focused when diving (潜水), "we can hear animals all around us," UK scientist Steve Simpson told the BBC.
In the past years, scientists used sound recorders to hear fish's "voices". There are now thousands of recorders in the ocean. They help scientists match sounds with sea life.
A healthy coral reef (珊瑚礁) is one of the noisiest places in the ocean. Scientists can tell if it's healthy by listening to it. A healthy coral reef should be full of clicks (咔嚓声) made by shrimps (小虾). When some coral reefs died in 2015 and 2016, they became quiet. After people set up the protected areas, scientists heard the animals come back.
By listening to the ocean, scientists start to understand sea animals' languages. Strong clownfish (小丑鱼) make short "chirp(啁啾声)" sounds when going after small clownfish. A damselfish(小热带鱼) can create a pop sound to scare other fish by quickly opening and closing its mouth. Mother dolphins can use a special voice to talk to their babies. They are saying "I'm here" to comfort the baby dolphins.
Scientists are building an online library called the Global Library of Underwater Biological Sounds(全球水下生物声音库). It will collect sounds from all over the world to check sea animals' health. Humans need to understand the sounds made by underwater animals before they die out.