Six years ago, the fish ecologist Rodney Rountree was on a skiff in the Peruvian Amazon. He was holding a piranha in his hand…underwater…in a river filled with other piranhas. Maybe, hungry ones. 

六年前，鱼类生态学家Rodney Rountree在秘鲁的亚马逊河上划船。他手里拿着食人鱼......水下......在一条充满其他食人鱼的河里。也许，饥饿的人。

"That thought crossed my mind a little bit. The water was essentially no visibility. So I did worry a little bit about that but there was no other way to do it."

“这个想法在我脑海中浮现了一点。水基本上没有能见度。所以我确实对此有所担心，但没有其他办法可以做到。”

The job he needed to do? "Audition them, for sound production." Because Rountree studies the sounds fish make. His nickname—and the name of his company: "The Fish Listener." 

他需要做的工作？ “试听它们，用于声音制作。”因为Rountree研究鱼的声音。他的绰号 - 以及他的公司名称：“The Fish Listener”。

So his team would catch a fish, reel it in and identify it. And then Rountree would hold it underwater, near a hydrophone, to capture the sounds it made. Like this one, from a red piranha. <> 

所以他的团队会捕到一条鱼，将它卷入并识别它。然后Rountree将它放在水下，靠近水听器，捕捉它所发出的声音。喜欢这个，来自红色的食人鱼。 << CLIP：piranha sound >>

"A lot of people call it a bark. I sometimes thought of it as a honk."

“很多人都称它为树皮。我有时会把它当作一种鸣叫。”

The fish make the sound, he says, by pushing and pulling on their swim bladder with the surrounding muscles. Overall, Rountree auditioned 129 piranhas, of four different species. Along with dozens of other river species, like catfish. And he found that he could differentiate individual piranha species by analyzing factors like pitch and harmonics and number of barks. 

他说，通过推动和拉动周围肌肉的游泳膀胱，鱼会发出声音。总的来说，Rountree试验了四种不同种类的129种食人鱼。与其他数十种河流物种一样，如鲶鱼。他发现他可以通过分析音高和谐波以及树皮数量等因素来区分各个食人鱼。

His colleague Francis Juanes presented the work at the Acoustical Society of America meeting in Victoria, Canada. [Rodney Rountree, Francis Juanes: Sounds from the Amazon: Piranha and Prey]

他的同事Francis Juanes在加拿大维多利亚州的美国声学学会会议上介绍了这项工作。 [Rodney Rountree，Francis Juanes：来自亚马逊的声音：Piranha and Prey]

Rountree also recorded 10 hours of underwater soundscapes, like this one, captured during a piranha feeding frenzy. <> There's a piranha honk, he says, and lots of catfish screeching. Which suggests that, with a bit more study, underwater recordings like these might give us a clearer glimpse of who's doing what, in murky waters.

Rountree还录制了10个小时的水下音景，就像这个在食人鱼喂食狂潮时拍摄的。 << CLIP：嘈杂的河流>>他说，有一条食人鱼喇叭声，还有许多鲶鱼尖叫。这表明，通过更多的研究，像这样的水下录音可以让我们更清楚地看到谁在黑暗的水域做什么。

—Christopher Intagliata 

[The above text is a transcript of this podcast.]