Interacting effects of short-term and long-term noise exposure on antipredator behaviour in sand gobies

In today's marine habitats, anthropogenic noise is widespread in space and time, affecting aquatic animal communities. Short-term exposure to noise is known to affect vital behaviours, such as the ability to evade predators. However, long-term noise pollution may lead to differences in short-term responses between naïve and experienced animals. We investigated the interaction between short-term and long-term sound exposure on the antipredator response of free-ranging sand gobies, Pomatoschistus minutus. We tested the effects of short-term boat noise playback on the response to a simulated predator strike in areas across a range of low to high long-term noise disturbance levels. Exposure to boat noise did not affect the startle response, time frozen or response latency of gobies to a predator stimulus. However, individuals exposed to short-term boat noise playback were absent from the experimental area for shorter periods after the predator strike than gobies exposed to the silent control. Moreover, gobies in long-term noisy habitats also stopped avoiding the area after the predator strike under silent control conditions. These changes point to a decreased magnitude in antipredator response, as a function of interacting short- and longer-term levels of disturbance. Thus, prey species alter their antipredator behaviour in ways that can potentially lead to higher mortality for individual prey. This could ultimately have implications at the level of the food web.