Environment Science

Whale sharks are bigger and live longer than had been thought, study finds

FORT LAUDERDALE, Fla. – Whale sharks, the largest of the shark species, can travel the ocean for up to 130 years and can grow as long as 61.7 feet, a study found.

Researchers at Nova Southeastern University’s Guy Harvey Research Institute and the Maldives Whale Shark Research Program, a nonprofit whale shark research group, did the research.

The study, published online this month in the Marine and Freshwater Research Journal, followed free-swimming sharks who returned to the same area every one to two years in the South Ari Atoll, the Maldives over 10 years.

The researchers wrote that at 61.7 feet on average, the sharks are “longer and bigger than previously believed.” The measurements were based on 186 encounters with 44 sharks that were measured visually and with laser and tape. Previously, whale sharks were generally believed to be 40 feet long or more.

“What makes this a novel approach is that we took repeated noninvasive underwater measurements of live sharks over the course of a decade,” said Cameron Perry, one of the study’s authors and a former graduate student at NSU in Davie.

“Up to now, such ageing and growth research has required obtaining vertebrae from dead whale sharks and counting growth rings, analogous to counting tree rings, to determine age,” Perry said. “Our work shows that we can obtain age and growth information without relying on dead sharks captured in fisheries. That is a big deal.”

Researchers said they were able to recognize the returning sharks because of their unique patterns of spots.

Whale sharks are plankton-eaters and can weigh about 20 tons. They are generally harmless to humans who have spotted them off the coasts of South Florida.

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Source URL: Google News

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