Washington, August 25 (ANI): A long-term field and DNA study by scientists has shown that that young lemon sharks, the equivalent of human ‘tweens’ and teenagers, born at the Bimini islands, Bahamas, tend to stay near their coastal birthplace for many years.

The study was carried out by scientists from the Institute for Ocean Conservation Science at Stony Brook University (SBU), University of Miami, Field Museum of Chicago and others.

While shark research and conservation typically focuses on baby sharks confined to shallow habitats, or ocean-roaming adults, less is known about these intermediate-aged animals, which are the breeders of tomorrow and are roughly similar in development to human ‘tweens’ and teenagers.

Tropical island-nations that sacrifice their nursery habitats to coastal development are therefore likely to lose not only babies but also much older sharks from their local areas, with potentially dire effects on the surrounding ecosystem.

“It takes some sharks more than a decade to reach reproductive age, so we set out to better understand the phase of their development from when they are a couple of years old until they are on the verge of sexual maturity,” said lead author Dr. Demian Chapman, shark scientist with the Institute for Ocean Conservation Science at Stony Brook University (SBU) in New York, and an assistant professor at SBU.

During the course of the Bimini study, from 1995 to 2007, over 1,700 immature lemon sharks were caught, tagged and released.

The implanted tags, plus subsequent recaptures and DNA analysis, showed that more than half of the 3- to 7-year-old sharks caught off Bimini were born locally and had lingered near their birthplace for years.

“We were very surprised to see that many lemon sharks lingered for years around the island where they were born - often more than half of their development to adulthood,” he added.

Fear of deep water -and the bigger predators that live there- combined with abundant prey in the mangroves around Bimini probably keeps these island-born sharks in safer waters near home for several years after their birth.

“This means that using marine reserves and other local conservation measures may help protect sharks born around tropical islands for much longer than we thought,” Dr. Chapman explained.

He suspects that future research could show that these stay-at-home behavior patterns are common among many shark species that live and breed around tropical islands.

“If island communities develop all of their shark nursery habitats, like mangroves, or overfish baby sharks in local waters, then they will subsequently lose a big chunk of the older sharks as well,” he said. (ANI)