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Highlights
Reef chorus strikes a chord with baby fish
Research has shown that sound is instrumental in attracting fish
larvae to settle on reefs. This research which was published in the
prestigious journal ‘Science’has shown for the first time that reef
fish not only locate settlement sites using reef sounds but also
discriminate between sounds.
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The work explains how baby fish (only
a few millimetres long) that are swept off the reef as larvae out
to open seas manage to find their way back again as juveniles,
some swimming many kilometres.
Sound travels in water irrespective of current flow, and reef
animals, especially fish, create a clamour that can be heard up to
15 km around a reef. At dusk and dawn, the cacophony of marine
noise reaches a crescendo. Experiments were designed to test
whether reef sounds direct the settlement behaviour of reef fish
recruits and were carried out off Lizard Island in Queensland’s
far north. Recordings of underwater reef noises were made, mostly
the sound of snapping shrimp and fish calls, then broadcast
through submersible speakers above small patch reefs made from
dead coral rubble. |
Young fish, like this juvenile black
and white seaperch, return from oceanic nurseries to coral reefs
by homing in on biological sounds.
Photo: V. Bates
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Species from 11 families including damselfish and cardinal fish
tuned in to the sound recordings. There was a preference for the noisy
reefs in some instances four times as many recruits arrived. Some of
these species preferred reefs where there was high frequency noise
like snapping shrimp, while others simply appeared to be attracted to
any sound.
This important use of sound at this critical life history phase
does raise the possibility of potential adverse effects of increasing
anthropogenic noise pollution but also may lead to the development of
new tools for fisheries managers for restocking fisheries or newly
established marine reserves.
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