Marine animals face many threats that can cause trauma to their body parts. Carnivores may try to remove a large chunk from them;They may be injured during mating behavior;Or those who live in coastal urban environments may come into contact with boats, resulting in scarring and even death all over the body. Now, however, fin regeneration after a traumatic event has been identified for the first time in silky shark species.
The silky shark (Carcharhinus faliformis) is a smooth marine carnivore that is about 35 m (11.)5 feet). They are claimed to have been one of the most common shark species in the ocean, but are now one of the most consumed species in the shark fin market.
In July 2022, off the coast of Florida, an underwater photographer and diver photographed a silk shark with an injured dorsal fin. The shark is an adult male, and marine biologist Chelsea Black, the author of a new study, looked at these ** to help identify the shark — the shark has a tag attached to it with numbers unique to the animal.
The researchers concluded that the most likely explanation for why sharks suffered such injuries was the purposeful removal of satellite tracking tags from their dorsal fins with sharp objects.
The shark, whose fins were injured, did not reappear in 2022 and is presumed to have left the Jupiter area of Florida as part of its annual migration. In June of the following year, an adult male silky shark returned to the same area with an unusually shaped dorsal fin. By matching the previous year's **id and tag number, the same one was identified despite a significant change in the shape of the dorsal fin.
From the 2022 year, the shark is believed to have lost about 20 in this incident8% dorsal fin. When the shark was photographed again 332 days later, it had healed 87% of its original fin size.
The special wound healing ability is not entirely unknown in marine species. Prior to this example, dorsal fin regeneration had been documented in whale sharks (Rhindon typus), the only other examples of dorsal fin regeneration to date, but healing of scratches and various other wounds has been seen in reef manta rays (Mobula alfredi), sand tiger sharks (Carcharias taurus), and lemon sharks (Negaprion acutedens).
The silky shark's wound is believed to have been completely closed 42 days after injury, and measurements of fin growth show a 10-fold increase in fin area7%, indicating that the fins are at least partially able to regenerate. This is consistent with the expected wound healing rate in other species.
Overall, these observations represent the first recorded case of dorsal fin regeneration in silk sharks and the second known case of dorsal fin regeneration observed to date. While the observation of this individual is scientifically interesting, the authors emphasize that if the satellite tag had never been removed, the knowledge that could have been used to better protect the entire species would have been lost. They further emphasized the need for effective communication between research and local communities in order to carry out successful marine conservation actions.