Assessing the impacts of anthropogenic sounds on early stages of benthic invertebrates: The 'Larvosonic system'.

Noise produced by human activities has increased in the oceans over the last decades. Whereas most studies have focused on the impact of anthropogenic noise on marine mammals and fishes, those focusing on marine invertebrates&nbsp; are&nbsp; rarer&nbsp; and&nbsp; more&nbsp; recent,&nbsp; especially&nbsp; when&nbsp; considering&nbsp; peri-metamorphic&nbsp; benthic&nbsp; stages,&nbsp; highly sensitive to&nbsp; anthropogenic perturbations. A&nbsp; careful review&nbsp; of the literature reveals&nbsp; a&nbsp; simplistic characterization of the acoustics within the containers used to quantify larval and juvenile responses to noise, thus weakening the conclusions of such works. To address this problem, we developed the Larvosonic system, a laboratory tank equipped&nbsp; with&nbsp; acoustic assets&nbsp; to&nbsp; assess&nbsp; the&nbsp; impacts&nbsp; of&nbsp; noise&nbsp; on&nbsp; young&nbsp; stages&nbsp; of&nbsp; marine&nbsp; invertebrates.&nbsp; We&nbsp; first provide&nbsp; a&nbsp; careful&nbsp; analysis&nbsp; of&nbsp; the&nbsp; tank&nbsp; sound&nbsp; field&nbsp; using&nbsp; different&nbsp; sound types,&nbsp; and&nbsp; we&nbsp; assess&nbsp; the&nbsp; effects&nbsp; of expanded polystyrene units on the sounds emitted by a professional audio system in order to dampen reverbera- tion&nbsp; and&nbsp; resonance. Then,&nbsp; we&nbsp; apply&nbsp; this&nbsp; acoustic&nbsp; calibration&nbsp; to&nbsp; the&nbsp; effects&nbsp; of&nbsp; both&nbsp; pile&nbsp; driving&nbsp; and&nbsp; drilling noises on postlarvae of the scallop bivalve Pecten maximus. Acoustic recordings highlight that diffuser and bass trap&nbsp; components&nbsp; constitute&nbsp; effective&nbsp; underwater&nbsp; sound&nbsp; absorbents,&nbsp; reducing&nbsp; the&nbsp; reflection&nbsp; of&nbsp; the&nbsp; whole&nbsp; fre- quency bandwidth. Scallop experiments reveal that both type and level of the tested noise influenced postlarval growth,&nbsp; with&nbsp; interactive&nbsp; effects&nbsp; between&nbsp; trophic&nbsp; environment&nbsp; and&nbsp; noise&nbsp; level/spectra. The&nbsp; Larvosonic&nbsp; system thus constitutes an efficient tool for bioacoustics research on bentho-planktonic invertebrate species."<br>
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