A really interesting new paper has been published that looks at the potential for underwater noise to interfere with communication between mother-calf pairs of North Atlantic right whales.
Vocalisation is vitally important for marine mammals and it is involved in critical activities including foraging, socialising and reproducing for many species. If underwater noise is too loud then it can impact on these important vocalisations. This can lead to marine mammals changing their vocalisations in order to make themselves heard.
Much of the underwater shipping noise worldwide is low-frequency and overlaps with the main frequency range of baleen whales. This study investigated the potential effects of underwater shipping noise on the upcall vocalisations associated with critical reunion events between mother and calf pairs of endangered North Atlantic right whales. The authors used acoustic propagation modelling to predict how the sound intensity of upcalls decreases over distance (transmission loss) and how the whales could adapt their vocalisations.
They showed that noise from both nearby container ships and from distant shipping can limit the distance at which the upcalls can be heard. This means that the communication space between the mother and calf would be reduced. They also describe how the whales could adapt the amplitude (volume) and frequency (pitch) of their upcalls to compensate for this.
Check out the full paper here.