Testing mortality of fish larvae due to simulated offshore piling noise.

Abstract

Driven by the concern that impulsive noise produced by offshore pile driving may lead to mortality of fish larvae, a device was developed for testing the sensitivity of small fish and fish larvae to sound exposure. The device consists of a rigid‐walled cylindrical chamber (110‐mm diameter, 160‐mm height), driven by an electrodynamical sound projector. Samples of up to 100 larvae can be exposed simultaneously to a homogeneously distributed sound pressure and particle velocity field, at a controllable static pressure up to 3 bars. Two configurations are available with either a dominant sound pressure or a dominant particle velocity exposure. Recorded piling noise can be reproduced in a controlled way, in the frequency range between 50 Hz and 1 kHz, at zero to peak pressure up to 40 kPa and single pulse sound exposure levels up to 187 dB re 1 μPa2 s, or peak particle velocity up to 2.2 cm/s and integrated square particle velocity level 124 dB re 1 (nm/s)2 s. Tests are carried out in which sole (Solea solea) larvae at different stages of development were exposed to various levels and durations of piling noise.