Passive acoustic monitoring shows no effect of anthropogenic noise on acoustic communication in the invasive round goby (Neogobius melanostomus)
Abstract
Passive acoustic monitoring (PAM) can be a powerful tool to survey populations of soniferous species in natural settings. Using PAM allows monitoring of behaviour and activity unobtrusively to get a more accurate assessment of behavioural responses than traditional techniques. The use of PAM can also be beneficial for behaviourally cryptic species or other taxa that might be missed by more traditional sampling methods. To quantify seasonality of reproduction in an aquatic invasive species and to assess possible interactions between both abiotic and biotic noise and acoustic ecology, we deployed multiple hydrophones to fully characterise the acoustic behaviour of round goby (Neogobius melanostomus), a highly invasive species. We also aimed to quantify levels of anthropogenic noise around the goby communities. We tested correlations of round goby calling rates with overall noise levels and the presence of boat traffic as direct tests of the hypothesised role of noise on natural acoustic behaviour of fish. Round goby showed a clear diel patterning of calling behaviour, with the highest activity during the night and ceasing at midday; supporting the importance of acoustic—as opposed to visual—signalling for mate attraction. Calls also allowed us to pinpoint spawning areas for possible remediation. We saw no correlation between measures of background noise and calling behaviour or presence of boats and calling, suggesting that increased levels of noise have no effect on the natural calling behaviour of this species. Passive acoustic monitoring of round goby calling behaviour is a promising technique for those interested in remediation of this highly invasive species, as it can be difficult to quantify population levels by more conventional means. The lack of noise effects we see suggests that noise from recreational boats does not disrupt signalling in this species with limited hearing range, although more investigation is needed to ascertain whether noise could be a stressor in other contexts.