*Article* **Sea Lice Are Sensitive to Low Frequency Sounds**

**Marta Solé 1,\*, Marc Lenoir 2, José-Manuel Fortuño 3, Steffen De Vreese 1, Mike van der Schaar <sup>1</sup> and Michel André 1,\***


**Abstract:** The salmon louse *Lepeophtheirus salmonis* is a major disease problem in salmonids farming and there are indications that it also plays a role in the decline of wild salmon stocks. This study shows the first ultrastructural images of pathological changes in the sensory setae of the first antenna and in inner tissues in different stages of *L. salmonis* development after sound exposure in laboratory and sea conditions. Given the current ineffectiveness of traditional methods to eradicate this plague, and the strong impact on the environment these treatments often provoke, the described response to sounds and the associated injuries in the lice sensory organs could represent an interesting basis for developing a bioacoustics method to prevent lice infection and to treat affected salmons.

**Keywords:** sea lice; *Lepeophtheirus salmonis*; acoustic trauma; transmission electron microscopy; scanning electron microscopy
