Orcas off Mozambique are suddenly turning up every week, and scientists want to know why

Whale sharks, hammerheads and leatherback turtles are turning up too.

The timing has scientists asking an uncomfortable question: is El Niño behind it?

The sightings are being recorded by the Bazaruto Center for Scientific Studies (BCSS), which describes itself as Africa’s first permanent ocean observatory.

It sits on Benguerra Island in Mozambique’s Bazaruto archipelago, a popular holiday spot for South Africans.

WHAT SCIENTISTS ARE SEEING OFF MOZAMBIQUE

According to Bloomberg, via Moneyweb, growing numbers of orcas and whale sharks have started appearing off the coast of Mozambique.

BCSS chief scientist Mario Lebrato said the change was sudden.

“We had seen zero so far and all of a sudden I’m seeing them weekly, starting at the end of last year,” he said.

In one recent encounter, a BCSS research expedition spotted a group of 10 orcas in the Bazaruto seascape.

The observatory calls it an exceptional sighting for Mozambique and the tropical Southwest Indian Ocean.

IT’S NOT ONLY ORCAS OFF MOZAMBIQUE

Across the more than 7,000 square kilometres of ocean the observatory monitors, other unexpected species are appearing too.

These include leatherback turtles and more hammerhead sharks than usual.

The team also spotted a dolphin species it had never seen there before.

Whale sharks aren’t new to Mozambique. They’re well known further south, off Tofo Beach, where they’re spotted throughout the year.

What’s unusual is the rise in sightings across the area the observatory monitors.

IS EL NIÑO TO BLAME?

The sightings have coincided with the formation of El Niño.

According to Lebrato, changes in currents and water temperatures in the Mozambique Channel may be affecting plankton and other food sources.

But he’s careful not to jump to conclusions.

“Is it El Niño-connected? I don’t know,” he said.

He added that the animals don’t recognise borders. They simply move wherever conditions suit them, whether that’s Bazaruto, South Africa or Tanzania.

WHY SOUTH AFRICANS SHOULD PAY ATTENTION

That last point matters for us.

If ocean conditions keep shifting, marine life along South Africa’s coastline could change too.

South Africans already know orcas from the Western Cape, where a pair nicknamed Port and Starboard made headlines for hunting great white sharks in False Bay and off Gansbaai.

BCSS collaborator Dr Maeva Terrapon is also preparing the first photo-identification catalogue of orcas in the tropical Southwest Indian Ocean, using records from Mozambique, Tanzania and elsewhere in the region.

In time, catalogues like this could help scientists track whether the same animals are moving between countries.

The idea of orcas cruising past a Bazaruto holiday island sounds magical.

But it’s also a reminder that the ocean is changing in ways we’re only starting to understand.

I’ll be watching this one closely, especially if those changes start showing up closer to home.

WOULD YOU LOVE TO SEE ORCAS ON YOUR NEXT HOLIDAY TO MOZAMBIQUE?