I have attached the picture of the humpback dolphin taken past November in the Persian Gulf as part of my research there. I am not really sure if this type of mark could be caused by a propeller as it looks like that there are marks on the body. Has someone observed something similar in other dolphins?
To me it looks like the animal was injured by some type of fishing gear. Sam Ridgway
Hi Bruno, I would think it could be a net entanglement related mark. I think the article I have attached could be useful for your case.
Cheers
Chiara
Hi Bruno,
Have seen similar stuff on the dolphins in Mauritius, I would agree with both of the above, fishing gear entanglement
Hi again Bruno, I agree with all the answers above. The type of healing pattern reflects a straight deep injury similar to what you would expect from a monofilament cut. I've seen several of these in bottlenose dolphins.
Could be wire of the fishing gear but most probably is net caused injury
Many thanks for your answer, I also was thinking that a gillnet could be the cause of the injury however I wanted to exclude other options. Thanks again
I also agree with the above answers and most probably the injury could be due to gill net. I have worked on irrawaddy dolphins in Chilika Lake, India and during our study we have observed similar fin patterns. Mostly gill nets are used there for pelagic fishing.
Yes, this is likely a net where the square of the open mesh caught over the dorsal fin. With resistance during swimming it looks like it embedded as it cut into the tissue over time. Some fins and flippers have self amputated this way. In this case, there does not appear to be any line left, and the healing process seems to have adequately resolved the lesion.
It is difficult to be sure there was the presence of a net. However the presence of a rope thicker than a fishing line) is quite sure as shown by the main mark in the front of the dorsal fin. Its depth is linked to the streching and struggling following the entanglement which was probably circular to the body as suggested by the two other marks that are posterior to the fin.
I agree with the above - entanglement in fishing gear seems the most parsimonious explanation. I have seen similar marks on sharks in areas where gillnets are regularly deployed - although sharks heal more thoroughly afterwards.
I also agree that it looks like an entanglement mark. We see similar markings on dolphins in Hawaii from interactions with long-line fishing gear.
Agreed with above; definitely a binding wound with erosion into the skin. The mark on the leading edge of the dorsal fin is likely due to drag/friction resistance as the entangled line wore into the dermis as the whale traveled forward. The indentation on the caudal edge of the fin implies a constriction wound typical of a torn gillnet or a mass of debris wrapped around the fin.
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