Ocean Noise Pollution Leads Baby Fish Away From Good Habitat

damselfish photo

photo: Andreas März via flickr

Another one of the detrimental effects that human-caused noise pollution in the oceancan have on wildlife: According to a UK-led team of researchers working in the Great Barrier Reef, increasing noise could cause baby fish there to be led astray as they swim from where they are born to their adult habitat, causing their death.Baby Fish Learn, Remember & Use Sounds to Find Home
Dr Steve Simpson of the University of Bristol:

When only a few weeks old, baby reef fish face a monumental challenge in locating and choosing suitable habitat. Reef noise gives them vital information, but if they can learn, remember and become attracted towards the wrong sounds, we might be leading them astray.

Previous research by Simpson has shown that baby reef fish use sounds made by other fish, shrimp and sea urchins as cues in finding coral reefs.

Simpson says though that as anthropogenic noise increases, something which he notes is ongoing, with "small boats, shipping, drilling, pile driving and seismic testing now sometimes drowning out the natural sounds of fish and snapping shrimps. If fish accidentally learn to follow the wrong sounds, they could end up stuck next to a construction site or follow a ship back out to sea."

But wait, you say. Don't fish have absurdly short memories? Isn't every turn a fish takes in a tank essentially a brand new scene to them? Not so, notes Simpson--who says his new research "shows that fish can learn a new sound and remember it hours later, debunking the 3-second memory myth."

Fish Confused by Non-Natural Sounds
Here's why:

Using underwater nocturnal light traps, Dr Simpson and his team collected baby damselfish as they were returning to coral reefs. The fish were then put into tanks with underwater speakers playing natural reef noise or a synthesized mix of pure tones. The next night the fish were put into specially designed choice chambers (long tubes with contrasting conditions at each end in which fish can move freely towards the end they prefer) with natural or artificial sounds playing. All the fish liked the reef noise, but only the fish that had experienced the tone mix swam towards it, the others were repelled by it. (University of Bristol)

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More on Noise Pollution & Oceans:
Noise Pollution Harms Fish Populations, Locations, Habits
To Get Home Baby Corals Dance to Reef Music
Human-Generated Noise Yet Another Threat to Northern Right Whales

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