as a follow-up top anyone that cares. I sent an e-mail to the Bottlenose Dolphin Research Institute and asked about the markings on the dolphins. This is the reply I got.
Dear Marc,
the lines and scratches present in your picture are mainly teeth lines, they are a result of social interaction between the individuals. These marks are natural and they are normal for dolphins.
Congratulations for your pictures I love photography and it was nice to see your gallery,
Regards,
Bruno Diaz Lopez
Research Chief / Director
Bottlenose Dolphin Research Institute BDRI
Via Diaz 4, Golfo Aranci (OT) 07020 Italy