Thankfully, a scuba diver doesn't have a closed swim bladder to worry about.

幸好潜水员们没有鱼鳔，自然不用担心这种问题。

And it allows the swim bladder to reverberate. Much like any sort of drum.

这是通过收缩鱼鳔周围的肌肉所发出的声音。“它让鱼鳔发出回响。非常像鼓声，像充气的腔室。”

The fish make the sound, he says, by pushing and pulling on their swim bladder with the surrounding muscles.

他说，鱼类通过鱼鳔周围的肌肉推拉鱼鳔来发出声音。

So, any air-filled spaces, like a rockfish's swim bladder, or human lungs, will compress as they descend deeper and expand as they ascend.

所以像石斑鱼的鱼鳔或人类的肺部，这类充满气体的器官，在个体下潜的时候会被压缩，而上浮的时候会随之膨胀。

After a fish bites a fisherman's hook and is quickly reeled up to the surface, the air in its swim bladder begins to expand.

所以当鱼上钩并且快速浮向水面的时候，鱼鳔内的空气会随之膨胀。

Unlike most other fish, the ones that live in these depths don't have gas-filled cavities like swim bladders that would collapse under the extreme pressure.

和其它鱼不同，生活在深海中的生物没有空气囊，即鱼鳔儿，鱼鳔会被强大压力破坏。

Swim bladders are often filled with air, which fish gulp down to help keep them buoyant.

鱼鳔通常充满空气， 鱼会吞下这些空气以帮助它们保持浮力。

It is often caught as by-catch by fisherman trying to capture a species of endangered fish for a lucrative trade in their swim bladders to China.

因向中国售卖鱼鳔获利，许多濒危物种遭到渔民意外捕获。

Their swim bladders are split into two, and so full of blood vessels that they look basically just like our lungs do.

它们的鱼鳔一分为二，充满了血管， 看起来就像我们的肺一样。

By rapidly contracting specialized muscles above their swim bladders, they repeatedly " bark" when they're facing off with one another or when captured.

通过快速收缩鱼鳔上方的特殊肌肉，它们在彼此对峙或被捕获时会反复“吠叫” 。

In this context the air-filled swim bladders that bony fish have evolved to preserve buoyancy are particularly reflective, and thus noticed by them.

在这种情况下，硬骨鱼为保持浮力而进化的充气鱼鳔特别反光，因此被它们注意到。

As for where these lungs came from, experts think they derived from an organ that many modern fish still have today: a swim bladder.

至于这些肺从何而来， 专家认为它们来自许多现代鱼类至今仍拥有的器官：鱼鳔。

The thinking is that, among some lobe-finned fish, the swim bladder became bigger and contained more blood vessels, so it became better at putting oxygen into the bloodstream.

他们的想法是， 在一些叶鳍鱼中，鱼鳔变得更大并且包含更多的血管，因此它更善于将氧气输送到血液中。