Between natural sounds and man-made sounds, the oceans are actually quite noisy places!
Large whales have excellent hearing, and at times can be easily disturbed by noise. Overall, it is assumed that a whale could detect and avoid an oncoming vessel. In reality, they don’t, and vessel strikes (collisions) are far too common.
Part of the problem is that sound travels more than 4 times faster in water than air because water is denser than air, making it unlikely that a whale will be able to detect which direction the sound is coming from until it is too late to react.
Another thing to consider is that whales do not seem to have a well-developed defense mechanism while at the surface because they are some of the largest animals on the planet and have very few predators. Except when in extremely close proximity, whales may not perceive an approaching vessel as a threat, or the whale may be intently focused on an essential behavior such as feeding or mating, and thus fail to react. Our current understanding is that they may not perceive oncoming vessels as threats and, in many cases, do not try to avoid them (see articles below). Ultimately, it’s the vessel operator’s responsibility to avoid whales, not the whales responsibility to avoid boats.
As the amount of ocean noise grows, so does the concern over the potential impacts on marine species and habitats. For whales, exposure to these noises can cause immediate effects such as behavioral disruption and impacts on hearing. They can also result in longer-term effects, such as the masking of critical sounds (think communication with other members of their species) or increased stress.
A Whale’s World of Sound – NOAA Fisheries
Why do whales make sounds? – National Ocean Service
Whale Navigation – Jean Michel Cousteau Ocean Adventures
Why don’t whales get out of the way of vessels? – Hakai Magazine
Simultaneous tracking of blue whales and large ships demonstrates limited behavioral responses for avoiding collision – Endangered Species Research (ESR)
Written by Max Tritt, NOAA Fisheries – Updated 8/14/2023