The research conduced at Bimini at The Bahamas has confirmed this behavior, which researchers had speculated for years.
Over a twenty year period, researchers found that female sharks returned 15 years later to the same spot they were born, and were not wanderers as previously assumed. Similar behavior has been seen in other animals, most commonly salmon and sea turtles.
“We found that newborn sharks captured in the mid-1990s left the safety of the islands when they were between five and eight years old. Yet, despite leaving and visiting many other islands in their travels, these sharks ‘remember’ where they were born after a decade of roving, and are able to find the island again when they are pregnant and ready to give birth,” said Dr. Feldheim, lead author of the study.
Bimini was an ideal location to track these sharks because the lagoon is like a lake, making it easier for researchers to capture the sharks and check whether the females actually came back to the same spot.
The previous lack of conclusive proof was due to difficulty tracking the movements of sharks from birth to maturity. The researchers used the sharks' DNA to create a giant family tree and used it to track sharks returning to the islands.
The research underscores the need to protect the nursery areas for these sharks, as overfishing has left left shark populations very vulnerable. Shark are fished for their fins, a delicacy in some Asian countries.
[Stony Brook University]