Science society hosts talk on manta rays

The Maldives Science Society in affiliation with Aqua Dreams Imagine (ADI) hosted a talk by Anne-Marie Kitchen-Wheeler on manta rays in the Maldives at Hiriyaa School.

The talk attracted around 120 people, mostly keen high school students eager to hear about the manta rays the Maldives is famous for.

After first visiting the Maldives in 1983 as a tourist, Anne-Marie has since dedicated her life to these creatures, conducting research for her PhD at the University of Newcastle in the UK alongside her work as a dive instructor. With over 4,000 dives in the name of research, she has spent almost half a year underwater.

Anne-Marie explained that mantas have evolved and adapted to their environment over 400 million years, and certain species can grow up to almost seven metres in length – the size of a London double-decker bus. However the Maldives mostly attracts smaller mantas, she explained.

“A typical day of a manta will begin hanging around 150 metres deep at dawn, to catch the plankton that has risen during the night,” she told the audience, adding that mantas don’t need to sleep.

“Early to mid-morning the mantas visit cleaning stations (where juvenile wrasse pick parasites and dead skin from the manta’s surface) and enjoy a massage. In the afternoon they snack, and in the evening they travel to deeper waters to continue feeding.”

Mantas are often confused with sting rays, but mantas do not sting and have a barb-less tail. In fact many mantas can be seen with their tails bitten off, typically by sharks.

The markings on the manta’s underside between the gill slits act as a fingerprint used for the identification of different individuals.

Anne-Marie explained that the Maldives offers one of the best chances in the world to see a manta in the wild, with groups of up to 200 individuals gathering to feed at certain times of year. The result is a huge attraction for tourists and big business for the dive industry.

Research suggests the populations are currently healthy, she noted. “Populations change year to year, but no general declines have been observed,” she said.

However mantas only reproduce every 2-3 years, and the single birth gestation takes 12 months. This means they need protection as an entire population can be wiped out by one year of continued fishing.

“The situation currently OK in Maldives though, as mantas are not fished and tourism brings in a very high price,” she said.

For the best chance of getting up close to a manta divers should swim low, she explained. Mantas are territorial and swim vertically belly-to-belly to size each other up, and the smallest one swims away low. By swimming low, divers can show they pose no territorial threat.

Kate Wilson is a marine biologist with the Environmental Protection Agency.

Photo by Lisa Allison

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