Home­com­ing sharks

Lemon sharks re­turn to birth­place, ex­hibit­ing ‘na­tal hom­ing’.

The Star Malaysia - Star2 - - ECOWATCH - By EMILY C. DOO­LEY

A STUDY by a team of re­searchers, in­clud­ing two from Stony Brook Univer­sity, shows sex­u­ally ma­ture fe­male lemon sharks re­turn to their place of birth to have their own lit­ter of pups.

The find­ings, pub­lished in the jour­nal Molec­u­lar Ecol­ogy, of­fer the first ev­i­dence that lemon sharks exhibit “na­tal hom­ing” de­spite hav­ing spent years away from their nurs­ery.

The study is based on re­search dat­ing to 1995, when re­searchers in the Ba­hamian is­land of Bi­mini be­gan tag­ging and tak­ing tis­sue sam­ples of lemon sharks. The sharks, named for their colour, tend to stay where they are born, seek­ing pro­tec­tion from preda­tors in the lo­cal man­groves un­til they are about five years old.

The fe­males be­come sex­u­ally ma­ture be­tween 15 and 17 years old and re­turned to Bi­mini when car­ry­ing their young, on av­er­age about ev­ery two years. They can have as many as 18 pups at a time and the brood can have be­tween two and five fa­thers, said Kevin Feld­heim, man­ager of Chicago’s Pritzker Lab­o­ra­tory for Molec­u­lar Sys­tem­at­ics and Evo­lu­tion and the study’s lead au­thor.

Many re­turned con­sis­tently. “We’re real- ising these nurs­ery ar­eas are re­ally vi­tal for these pop­u­la­tions,” he said. “There’s some fe­males that have been giv­ing birth (in the re­search area) the en­tire course of the study.”

Find­ing that sharks, widely thought to be a roam­ing species, have a hom­ing abil­ity to re­turn to spe­cific places could help na­tions and re­gions im­ple­ment spe­cific fish­ing bans or create sanc­tu­ary ar­eas to pro­tect the species.

“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 and ex­ec­u­tive di­rec­tor of the In­sti­tute for Ocean Con­ser­va­tion Science based there.

The find­ings could be ap­pli­ca­ble to other species, she said.

In 2011, the Ba­hamas en­acted an­tipoach­ing leg­is­la­tion pro­tect­ing more than 40 species of sharks from hunt­ing.

Shark fins are a prized del­i­cacy and with two dor­sal fins, lemon sharks of­ten fall prey.

“I re­ally think that there is not a species of shark on this planet that would be re­jected for its fin,” Pik­itch said.

Palau, the Mal­dives and Hon­duras also ban shark hunt­ing.

“Na­tional ef­forts to rein in the shark fish­ing in­dus­try by many coun­tries are likely to ben­e­fit hom­ing shark species, like lemon sharks,” Stony Brook as­sis­tant pro­fes­sor Demian Chap­man, also a study au­thor, said in a news re­lease. – www.news­day.com/ McClatchy Tri­bune In­for­ma­tion Ser­vices

The fe­male lemon shark be­comes sex­u­ally ma­ture be­tween 15 and 17 years old and re­turns to her birth­place when car­ry­ing her young.

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