The Lombard effect in fishes: How boat noise impacts oyster toadfish vocalization amplitudes in natural experiments

The Lombard effect (an involuntary increase in vocal levels in noisy environments) has been shown for humans, birds, and mammals. Here, we use experimental playbacks of vessel noise and other natural sounds in the normal soundscape of the oyster toadfish Opsanus tau to test if the Lombard effect occurred. Experiments were conducted at a noisy site adjacent to a port with high vessel traffic and in a quiet embayment. We played back vessel noise...