Fast boats like this one sometimes deliberately cross groups of dolphins at high speed, without even stopping or slowing down.
The risk of propeller strikes resulting in body lesions obviously exists, even in the case of fast-moving animals such as striped and common dolphins.
Lesions that are possibly cased by propellers have been photographed several times in the Gulf of Corinth, Greece. While wounded animals may recover, deeper lesions can result in mortality or impairment.
(Photos by S. Bonizzoni)