Sharks are generally considered a roaming, nomadic species, which is why scientists were surprised to discover that lemon sharks returned to their place of origins to give birth, Newsday reported.
Lemon sharks spend the first five years of their lives in the Bahamian island of Bamini (where they swim among the mangroves, or sea trees, to avoid predators) so they do have a deep connection to their birth place.
It takes at least another ten years (spent away from Bamini), however, for the yellow-brown sharks to reach sexual maturity -- meaning they possess a certain level of "natal homing" uncharacteristic of their genus, Newsday reported.
Kevin Feldheim, who co-led the study along with several researchers from Stony Brook University and the guidance of project founder Samuel Gruber, began tagging and examining the sharks in 1995. His report, published in the journal, "Molecular Ecology," represents over twenty years of data collection, according to Newsday.
"We're realizing these nursery areas are really vital for these populations," Feldheim said. "There's some females that have been giving birth [in the research area] the entire course of the study."
A deeper understanding of lemon sharks' migration patterns will help conservationists better protect them, according to the study. Shark fins are considered a delicacy in some countries; lemon sharks have two.
"There are a lot of conservation implications of these scientific findings," said Ellen K. Pikitch, a professor at Stony Brook's School of Marine and Atmospheric Sciences.
"National efforts to rein in the shark fishing industry by many countries are likely to benefit homing shark species, like lemon sharks," said Stony Brook's marine sciences school assistant professor Demian Chapman, who also contributed to the study.
Lemon sharks are also common along the southeastern coast of the United States and are used frequently in research because they tend to fair well in captivity, according to Enchanted Learning. The sharks used in this study conglomerated in a Bamini lagoon researchers compared to a lake, making them relatively easy to tag even in their natural environment.
"The lagoon in Bimini is almost like a lake," said Gruber, president and director of the Bimini Biological Field Station Foundation. "I realized that we had a chance to capture nearly every shark born into the lagoon each year, and this gave us the unique opportunity to see if the females actually come back to give birth. However it took us nearly two decades and countless hours in the field and laboratory, but we finally answered this long-standing question and many others with this paper."
