Southern right whales and great white sharks are disappearing from the waters around Cape Town, South Africa.
A recent survey conducted by the Whale Unit of the University of Pretoria’s Mammal Research Institute, and reported by Bloomberg, found that the southern right whales have revealed the second-lowest incidence of the mammals in more than two decades. Scientists believe the decline is due to climate change.
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The news about the whales follows a recent and similarly discouraging finding that great white sharks have disappeared from False Bay, which is off the east coast of Cape Town. Not a single shark has been seen this year, which is causing concern among the local tourism industry.
Shark dives that allow tourists to be lowered into the sea in a cage and whale watching are both big tourist attractions for the region.
The whale population in the area has apparently declined from more than 1,000 last year in False Bay to about 200 this year, according to a statement issued by the University of Pretoria.
The downward spiral in the population may be tied to climate conditions in the Southern Ocean, which lies off the Antarctic, Bloomberg reported.
“We believe the whales are not finding enough food, due to changes in the climate conditions of the Southern Ocean, possibly related to climate change,” the unit said. “Right whales eat krill and copepods and with not enough food they cannot store enough energy to complete the costly migration and reproduction. This has implications for population recovery.”
Great white sharks, meanwhile, play a major role in South Africa’s shark-diving industry, have not turned up in the region for a year and a half.
To provide some historical perspective, between 2010 and 2016, the Shark Spotting Programme reported about 205 sightings along False Bay’s beaches. By 2018 that number had dropped to 50. This year there have been no sightings at all.
What’s more, there have been no sightings at nearby Seal Island either, a place that once served as a feeding ground for the sharks.
“Further supporting evidence of the absence of these large apex predators is the lack of any feeding or bite marks on whale carcasses the city has removed from False Bay this year,” Cape Town’s municipality said in a statement, according to Bloomberg. “We do not know how their absence from False Bay would affect the ecosystem. Neither do we know the causes for their disappearance.”