The African penguin is expected to go extinct in the wild in just over a decade, given its current population decline. The main reason is a lack of food caused by disturbance to ocean conditions from global heating and competition from the commercial fishing industry. According to a study, scientists have identified a possible additional cause, one that is an entirely new threat and that further prevents the penguins from finding food: noise pollution from marine (海洋的) ships in a bay.
Since 2016, a new shipping practice has started at Algoa Bay. The bay offers ship-to-ship refueling for ships anchored offshore. Since the start of this practice, marine traffic in the bay has doubled. The number of bulk carriers (散货船) pulling into the bay has increased by ten times as much. Thus the noise levels in the area had doubled and the population of penguins has dropped sharply. High noise levels affect the ability of marine animals to find food, communicate or navigate properly.
Researchers used data from ship identification tools to estimate underwater noise from passing ships. They also attached underwater microphones and accelerometers (感应器) to some of the penguins. Recording the noise will tell researchers what the penguins are hearing, if they're talking while hunting, if they're changing their movements in response to noise, and if the noise is drowning out their hunting conversations. This will allow researchers to determine whether the sound disturbance is a direct cause of the penguins' ongoing difficulties in finding sufficient food.
The study is the first to explore he effects of ocean traffic noise pollution on seabirds and the consequences of offshore shipping activities on underwater noise levels. Experts are considering proposing various global best-practice approaches to reduce some of the impacts of noise pollution, such as policies that limit the number and size of ships allowed into a bay of this kind. "We also need more scientific monitoring of noise, before these measures are put in place and afterward, so that we have a proper understanding of what works. " a researcher said.