Shark amazes researchers with remarkable dorsal fin regeneration

A silky shark ( ) has stunned researchers with its miraculous recovery over a year after suffering a major lesion to its dorsal fin. As per , the shark was the first captured by an underwater photographer and diver in July of 2022 off the coast of Florida. The shark was photographed with a large rip in its dorsal fin.

Astonishingly, the latest images of the shark, taken 332 days later, reveal a nearly complete restoration of its fin. A new study conducted by Chelsea Black of the University of Miami reveals this unusual occurrence. "Prior to this study, there existed only one other documented case of dorsal fin regeneration making this study only the second record of dorsal fin regeneration in sharks to the author's knowledge," noted the research paper.

, the gruesome injury appeared to be a result of human interference, implying that someone captured the shark, maybe by accident while fishing, and purposefully removed its tag with a sharp weapon. The torn area appeared at the body area where experts had previously tagged the shark, leaving them puzzled about the motive behind this act.

Upon seeing the initial photos, the author expressed concern about the shark's ability to swim and feed effectively with such a mangled dorsal fin. However, recent images paint a different picture, as the shark has regained much of its fin, is swimming normally, and appears healthy. Researchers still don't understand how the silky shark's dorsal fin healed in such a short time.

Without access to the shark itself, “researchers can't be sure if this remarkable healing process is due to new tissue, scar tissue growth, or fusion of the wound bordering parts,” noted the report. As scientists strive to unravel the mystery behind how the silky shark orchestrated its remarkable recovery, it also underscores the urgency for conservation initiatives to shield these marine creatures from the perils of human induced harm.

The study was reported in the . Tissue regeneration and wound healing remain extremely understudied in elasmobranchs as many wounds are recorded through one off opportunistic observations with an inability for long term monitoring of individuals. This study demonstrates partial fin regeneration of a silky shark (Carcharhinus falciformis) almost one year after a traumatic injury that resulted in a 20.8% loss of the first dorsal fin.

The shark was photographed 332 days after the recorded injury with a newly shaped dorsal fin that had healed to 87% of the original size. Photographs provided by divers allowed for accurate measurements of fin growth, confirming an approximate 10.7% increase in fin area, indicative of tissue regeneration.

Wound healing rate was calculated to conclude that the initial wound reached complete closure by day 42, which is analogous with other elasmobranch healing rates. Prior to this study, only one other record of dorsal fin regeneration had been documented in a whale shark. This provides the first evidence of dorsal fin regeneration in a silky shark and contributes to the limited studies of wound healing rates in sharks.

This newfound insight into tissue regeneration and wound healing underscores the importance of further research to understand how they respond to traumatic injury in the face of mounting environmental challenges, both natural and anthropogenic. Additionally, this study exemplifies the power of collaboration between researchers and the public, including photographers and divers, to expand the scope of research studies and bridge the gap between science and society..