The noise egg: a cheap and simple device to produce low-frequency underwater noise for laboratory and field experiments

Studying the effect of anthropogenic noise on animal behaviour and physiology is a field of growing scientific and management interest. Anthropogenic noise is internationally seen as major environmental concern, but knowledge of the response of animals to noise and its ecological and evolutionary consequences is disparate. Even though fish and invertebrates form the majority of aquatic taxa, the effects of noise on these taxa are largely understudied. Especially the consequences of noise for short-range communication and behavioural interactions are yet unknown. While experimental studies on this subject are thus greatly needed, the expense of the equipment can be a main factor limiting data generation. Speakers that produce low-frequency sounds under water are currently either too large or too expensive to allow for sufficient replication in many research set-ups.
Here, we describe a device that can produce a low-frequency sound, which can be used as an experimental source of noise bo...