A new paper from the Goldbogen Lab at Stanford University suggests that blue whales lack the ability to avoid large cargo vessels.
Blue whales, the largest animal ever to live, were studied by the lab by tagging animals with GPS and dive-logging tags and observing the interactions with large vessels as the animals moved through their environment. The study represents the first direct observations of how blue mights attempt to avoid cargo vessels. The closest approaches of vessels to the whales in the study ranged between 60 and 3600 metres. The video below shows the closest approach – show the animals lateral movement (blue) relative to the boat (red) and the animals dive behaviour (bottom graph).
Animals were observed making a slow, shallow dive as vessels approached, but that this late and relatively small evasive approach may be indicative that animals lack the ability to avoid the vessels at close ranges. Animals didn’t make any observed lateral (i.e. sideways) movement in advance of the ship approaching. It is still poorly understood as to how the animals detect the vessels. Cargo ships generate significant amounts of underwater noise, but that does not mean that animals will necessarily be able to know exactly where the vessels are.