How did this shark swim a record-breaking 4,000 miles—a journey once thought impossible

Then she disappeared on March 25, 2022 and wasn’t seen again until Hakeem’s crew caught the shark on July 11 last year.

As part of their shark migration research, Daly and his colleagues also tagged and tracked 102 bull, blacktip, tiger and reef sharks in southern Africa. The longest recorded migration among these sharks was 1,400 miles, just one-third the distance traveled by the female bull shark that ended up near Lagos.

Bull sharks are coastal species, not known for long-distance travel in the open ocean. They prefer shallow waters where freshwater meets the sea and need water temperature warmer than 65°F.

 During her voyage north, the female bull shark had to navigate the Benguela upwelling, one of the world’s largest cold-water currents that extends along the west coasts of South Africa and Namibia. This upwelling has formed a cold barrier separating Africa’s bull shark populations for at least the past 55,000 years.

Scientists think this bull shark bypassed the cold water by swimming out around the upwelling, which can extend up to 90 miles offshore. It’s also possible she rode pockets of warmer water around South Africa into the Atlantic Ocean during a Benguela Niño event.