If fish could complain, they might say that they
can’t be heard above the noise. Scientists say fish can’t hear each other
because of motor boats and noisy engines.
Biologists say that fish make distinct sounds to
communicate with each other, to find a mate, and to assert territorial claims.
Fish make sounds with their swim bladders, and some fish are chattier than
others. Now biologists are investigating whether fish have regional accents.
British biologists are studying fish along the coastline of the United Kingdom.
Previous research has shown that European cod have
distinctly different accents to their transatlantic American cod cousins.
Professor Steve Simpson, a marine biologist at the University of Exeter in England,
says that the European cod is highly vocal. But as sea temperatures change, cod
are moving further north, and ‘fish with different vocal repertoires could be
pushed together and struggle to integrate, share territory and breed.’
Not only that, but the study showed that fish
communications are being drowned out by the noise of boat engines. Fish can’t
hear each other.
Simpson says seawater is hundreds of times denser
than air, so sound travels faster and further through seawater.
Male cod produce thumping and rumbling sounds as
they swim towards the surface with a female to convince her to release her
eggs. Parrot fish make crunching noises as they eat algae on reefs. Clownfish
in colonies make popping sounds to show dominance and purr to show submission,
while male midshipman hum to attract females.
The study found that the noise from marine traffic,
such as vessels and jet-skis, makes it difficult for fish to be heard amongst
themselves. Simpson’s study is investigating noise pollution in the coastal
seas around Britain and whether it is affecting the behaviour of cod, haddock,
and other fish species due to the barriers in communication.
Other research on coral reefs found that fish are
susceptible to noise pollution, but the effects of noise in Britsh waters are
not known, yet Britain’s waterways are some of the busiest in the world.
Simpson thinks that if fish communication is
interrupted due to noise, and fish can’t hear the timely mating and territorial
messages, their breeding habits might be affected, which may result in
declining fish stocks due to reduced breeding and territorial conflicts. I
guess shouting is not something fish do. And I wonder whether the research will
reveal whether fish have their own solutions to missed communications.
MARTINA NICOLLS is an international aid and
development consultant, and the author of:- The Shortness of Life: A Mongolian Lament (2015), Liberia’s Deadest
Ends (2012), Bardot’s Comet (2011), Kashmir on a Knife-Edge (2010) and The
Sudan Curse (2009).
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