Great Scallop (Pecten maximus)

 

“Coughing” sounds are produced by scallops as they rapidly contract the two valves of their shell to expel particle matter. Audio shortened for purposes of creating spectrogram. Sound courtesy of Lucia DI IORIO, CHORUS (released under Creative Commons Attribution, Non-Commercial)

Description

Pecten maximus, commonly known as the great scallop, is found in the northeast Atlantic. Like other scallop species, the great scallop is a bivalve, where the soft body is encased by a hardened exoskeleton  consisting of a hinged pair of shells known as valves. Scallops are benthic filter feeders; they feed (acquire nutrients) by passing sea water through a specialized filtering organ in their central cavity that sieves out and/or traps solids. 

To expel water, byproducts, and other substances from inside their central cavity, scallops produce a sharp “crack” followed by a long, puffing sound as the two valves close. These distinct sounds range in frequency from 20 Hz to 27 kHz and can be detected at ranges of up to tens of meters in natural ambient noise (Di Iorio et al. 2012). This sound is referred to as a “cough.”   

The great scallop can also swim, though this is a reaction that is generally used as a means to escape predators. A scallop’s swimming action is generated by rapidly opening and closing its two shells and expelling jets of water from each side of the hinge, causing the scallop to move backwards in the direction of the hinge. This motion also produces the coughing sound.

When a scallop swims and expels water, byproducts, and other substances from inside their central cavity, it produces its “coughing” sound.

Because scallops are expelling waste when they cough, the number of coughs in a given time period can be an indicator of the amount of suspended matter in the water. The density of scallops in an area has been shown to be an indicator of water quality in some coastal areas. The idea of using the sound produced by the scallops as a long-term indicator of water quality is being explored as a supplement to visual surveys of scallop density, which are very labor- and cost-intensive.

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