A rarely-seen blue whale washed up in Namibia – after a likely hit-and-run ship strike
- A blue whale was found floating off the coast of Walvis Bay by local tour operators on 26 April.
- Scientists from the Namibian Dolphin Project who investigated the scene are sure its cause of death was due to a hit-and-run ship strike.
- The blue whale is the world’s largest animal and is also listed as being critically endangered. Today less than 1% of its original pre-whaling size is left.
- Sightings of blue whales are incredibly rare along the southern African coastline, with only a handful recorded since whaling was banned.
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What was meant to be a very rare sighting of a blue whale by a tourism boat off the coast of Walvis Bay in Namibia was short-lived, when onlookers realised that the whale was dead. It was most likely killed in a hit-and-run-ship strike.
The blue whale, a young female measuring 18.3 metres, was found by local tour operators Laramon Tours on 26 April. They reported the carcass to the Namibian Dolphin Project (NDP), which conducts dolphin, whale and turtle research in Nambia and southern Africa. A fully grown blue whale can reach up to 30m in length.
The carcass washed onshore the next day, allowing the NDP to fully inspect its injuries.
"We are as confident as we can be without a full necropsy that the cause of death was 'ship strike'. It looks like the ship hit the flank, then the animal was rolled, and the fin was broken too. It likely died very quickly,” said Dr Simon Elwen, Director of Sea Search that overseas the NDP.
The incident is the first ever recorded stranding of this species in Namibia, South Africa or probably Africa since the end of commercial whaling, Elwen added.
“There are only a handful of sightings, less than 10, of live blue whales around southern Africa to date, mostly off western South Africa and Namibia, despite extensive observer effort,” said Elwen.
At this stage it remains unclear why the blue whale was in Walvis Bay in the first place. Blue whales are usually found offshore, well off the continental shelf, and their seasonal migrations and breeding and feeding grounds are generally poorly understood says Elwen.
Acoustic monitoring has shown regular detection of blue whale calls in deep waters off the south west Cape and northern Namibia during winter months (May-July). But not as close as the one found in Walvis Bay.
The blue whale is the world’s largest animal and is also listed as being critically endangered. The species was highly sought after for its oil with over 300,000 blue whales killed in the Southern Hemisphere alone, and a further 20,000 in the North Atlantic and North Pacific combined. The entire species was left on the brink of extinction until the practice was banned in 1966. Today, less than 1% of its original pre-whaling size is left - it is recovering at around 7% per year.
Rising marine traffic and whale conflict on the tip of Africa
With increased marine traffic around the tip of Africa ship strikes, along with entanglements in fishing gear, are considered to be a rising threat to several whale species that migrate along the southern African coastline.
It’s even more difficult to tell exactly how many whale species are impacted by ship strikes because not all animals that die will strand on a beach, says Dr Els Vermeulen, Research Manager of the University of Pretoria’s Mammal Research Institute Whale Unit based in Hermanus.
“In terms of the ship strike database there have been 75 to 80 confirmed fatalities due to ship strikes in the last 30 years.”
Most ship strikes occur around the Cape Town harbour, and along the Cape Peninsula.
“Knowing [whale] numbers are increasing, and that the West coast area is being used for feeding in the summer months, there is obviously a case that we need to keep our eyes out for more ship strikes. Just because of more whales being present along our shores. But as it stands [ship strikes are] not a threat to their populations.”
Considering the rising concern for whale safety, whale conservationists have been calling for voluntary slowdowns of ship speeds or diverting shipping routes. To date nothing to this effect is being done yet around southern Africa says the NDP.
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