Reg­u­lars help re­search

Pilbara News - - Pilbara News - Tom Zaun­mayr

Two of the Nin­ga­loo Ma­rine Park’s favourite an­nual vis­i­tors are be­lieved to be the long­est-stud­ied wild sharks in the world, ac­cord­ing to Mur­doch Univer­sity re­searchers.

Whale sharks Stumpy and Zorro have been com­ing to the Nin­ga­loo coast for 22 years and have given re­searchers an ex­tra­or­di­nary glimpse into the life of WA’s ma­rine em­blem.

One of the re­searchers watch­ing over them as they ma­tured has been Mur­doch Univer­sity re­search leader Brad Nor­man.

Dr Nor­man said the two 40year-old sharks had contributed sig­nif­i­cantly to the un­der­stand­ing of whale shark move­ments and iden­ti­fi­ca­tion meth­ods.

“I started back in 1994 and I was us­ing slide film to take pho­tos of whale sharks,” he said.

“Ev­ery­thing is dig­i­tal now, so it’s a lot eas­ier to get more pho­tos and mon­i­tor­ing done.

“Based on pho­to­graphs of the shape and length of the claspers, which are the paired ex­ter­nal re­pro­duc­tive or­gans of whale sharks up to 60cm long, Zorro first reached ma­tu­rity in 1998 and Stumpy in 2001.”

Iden­ti­fy­ing both sharks is easy be­cause of their unique tail fins but Mr Nor­man said ex­ten­sive re­search had proved dif­fi­cult at times as they may be sighted only once or twice a year.

Of more than 1300 whale sharks iden­ti­fied since re­search be­gan off the Nin­ga­loo coast, most sharks have been ju­ve­nile males who may hang around for only two or three years.

Dr Nor­man said the next fron­tier for re­search, of which he hoped Zorro and Stumpy would play a part, was to learn more about their breed­ing habits. “When they’re not at Nin­ga­loo, they must go some­where where they breed and that is still one of the big mys­ter­ies,” he said.

Pic­ture: In­dian Ocean Imagery

Stumpy and a swim­mer off the Nin­ga­loo coast.

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