【英语时差8,16】鱼，鱼，音乐鱼

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Don: Today on "A Moment of Science," herring make sounds when passing gas...

 

Yaël: Don, be serious!

 

D: I am serious, Yaël! The Atlantic herring is one of the most abundant fish on Earth!The silvery foot-long fish live in huge schools of thousands to hundreds of thousands of individuals.

 

Fishermen have long known that herring schools can release large clouds of bubbles that are visible from the surface. The bubbles are released through the anal opening, connected to the fish's swim bladder.

 

Y: What's a swim bladder?

 

D: It's a special, gas-filled organ that helps regulate buoyancy. Herring gulp¹ air at the surface and store it in their swim bladders. It's also long been known that herring make chirp-like sounds, especially when startled or in danger, but biologists didn't know how these chirps² were produced.

 

Y: I think I know where this is heading!

 

D: Yep! A pair of Danish biologists recorded herring housed in special pressurized tanks 

that replicated³ conditions at the ocean depths where herring are found. They discovered that the chirping⁴ sounds were actually produced by air release from the  swim bladder during the bubble production -- the first report of sound production by gas release in fishes.

 

Y: So the chirps are just a by-product⁵ of passing gas?

 

D: That is what's intriguing⁶ scientists, since the bubbles are released by the fish in response to stress, and occur whether the fish are ascending⁷ or descending⁸, they don't think that it's simply part of controlling buoyancy.

 

Some scientists speculate that the sound and bubbles might work as a visual and  acoustic screen to confuse predators⁹, but more studies are needed to determine if the  chirping bubbles have a behavioral function or not.   

 

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