Humpback whales are social animals. They typically stay alone, but sometimes gather in small groups, which separate after awhile. They communicate with one another, which helps them to find food. However, a new study from The University of Queensland discovered that ships actually disturb social activity of these whales.
Humpback whales typically stay alone, but sometimes gather in small groups to mate and feed. In fact, one of the more famous hunting methods of the humpback whales, called a bubble net, actually requires several animals. They swim in a circle, blowing bubbles on the boundaries of a school of small fish. They are making this circle smaller and smaller, until the fish are completely trapped and ready to eat in big gulps.
Scientists now analysed land-based observations of whale socialisation and matched this information with acoustic recordings using an offshore hydrophone array. They then compared data collected without the presence of ships with the time when vessels were around. Scientists found that whales are not communicating as much when ships are nearby. And so, their social interaction is disturbed and they are significantly less likely to gather into groups. In some cases their communication range was reduced by a factor of four, which means that they couldn’t hear each other over the noise that ships were making.
You are probably thinking about huge container ships and cruise ships and tankers. But this study was done mostly with fishing boats around. The noise that they are creating is enough to disturb the natural communication and socialization between the humpback whales and that is terribly sad news. However, scientists think this may be related to something else, not just the noise. Whales could be aware of the presence of the ships and communicate less when they are around.
Dr Rebecca Dunlop, author of the study, said: “There isn’t any evidence that our humpback whale population is under any pressure – they are increasing as rapidly as biologically possible. Therefore, any changes in breeding interactions in the presence of vessels likely has a negligible effect on the population”.
Scientists also mentioned that the impact of disturbed communication is greater in populations that were affected by whaling the most. The smaller the population in a particular area, the more it is going to be affected by effects of ships. However, this is going to be researched more. So far we know that whales cannot communicate as well when ships and boats are around, but we need to know how and if they adapt.
Source: University of Queensland