Researchers recorded piranha "honks" and catfish "screeches" in the Peruvian Amazon, which might illuminate fish activity in murky jungle waters. Christopher Intagliata reports.

　　研究人员在秘鲁亚马逊地区记录了食人鱼的“鸣笛”叫声和鲶鱼的“尖叫声”，这项研究可能会让人们对在丛林浑浊水域扑朔迷离的鱼类活动豁然开朗。-Christopher Intagliata报道。

　　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着单人小艇前行。 他手里拿着食人鱼，并把手放在充满其它饥肠辘辘的食人鱼的河里。

　　"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."

　　“这个实验想法在我脑海中一闪而过。水基本上没有能见度。所以我确实对此有点担心，但也着实没有其他的可行办法了。”

　　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."

　　他需要做什么工作呢? “试听采集它们，用于声音制作。” 因为Rountree研究鱼的声音，他得到了一个绰号，他将其作为公司的名称：“听鱼者(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.

　　因此，他的团队会首先捕捉一条鱼，将它控制住并对它做上标识。 然后Rountree将它放在水下，靠近水听器，捕捉它所发出的声音。就像这个来自一条红色的食人鱼的声音片段所示。 <录音片段：食人鱼的声音>

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

　　“很多人都称这种叫声像狗的吠叫。而我有时会将它称作一种类似汽车喇叭的鸣叫声。”

　　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，通过推动和拉动鱼鳔周围肌肉，食人鱼会发出上述声音。 总的来说，Rountree试验了四种不同类别的129条食人鱼，再加上其它数十种淡水鱼类，如鲶鱼等。 他发现他可以通过分析鱼的声音音高、声音的饱和度以及叫声数量等方面来区分各个种类的食人鱼。

　　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研究工作。 [Rodney Rountree，Francis Juanes：来自亚马逊的声音：食人鱼与其猎物。Sounds from the Amazon: 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个小时的水下声音场景，就像这个片段，它是在食人鱼进食狂潮时记录的。 <片段：吵闹的河流>他说，有一条食人鱼的喇叭声，还有许多鲶鱼尖叫声。 这表明，借助更多的进一步研究，像这样的水下录音可以帮助我们对浑浊水域下的鱼类活动达成更清晰的认识。