Stranded Humpback Whale at Robberg Nature Reserve

Stranded Humpback Whale at Robberg Nature Reserve

A young female Humpback whale that stranded on the Island Beach at Robberg Nature Reserve on Monday, 19 May 2025, was humanely euthanised the following morning after multiple failed rescue attempts and a subsequent expert assessment.  The incident mobilised a swift response from the Plett Stranding Network, CapeNature, marine mammal experts, and supporting partners including the National Sea Rescue Institute (NSRI) and the South African Police Service (SAPS).

The whale appeared to have run aground on a sandbank and Robberg Nature Reserve personnel were on site to monitor the whale and manage public access to prevent further distress or harm.  The whale, estimated to be between six and seven metres in length, was likely a calf from the 2023/2024 calving season.  “She appeared to be in good body condition, which made her a candidate for rescue,” said Chanel Visser, senior marine field ranger.  “It's possible she became stranded due to navigational error during her northward migration, or there may have been underlying health issues.”

In consultation with whale scientist Dr Gwenith Penry, the NSRI, and CapeNature rangers, the decision was made to attempt a refloat.  Over several hours, the team successfully guided the whale back into deeper water on several occasions.  However, the whale turned around and re-stranded on all attempts and the team stood down just before sunset.

Though rescue teams are trained and passionate, many factors work against a successful return to the sea.  The sheer size and weight of the whale is a challenge.  Whales can weigh tens of tons (this one likely weighed five to six tons).  Once on land, their own weight can crush their internal organs and cause irreparable damage.  The trauma of stranding, combined with dehydration and sun exposure, can put the animal into shock.  Even if a whale is refloated, it may strand again if it's confused, ill, or physically unable to swim effectively.  Strandings are rarely the result of one simple cause.  Often, they involve a combination of issues.  A sick or injured whale may lose strength or become disoriented, leading it into shallow water.  Whales use echolocation and shallow sloping beaches like those along the southern Cape can confuse their sonar.  In some species (not Humpbacks), whales strand together out of loyalty to one another, even if only one individual is in distress.  Shifts in ocean temperature, prey movement, or even underwater noise pollution can cause whales to enter unfamiliar or dangerous areas.

With the whale alive but stranded again on the morning of Tuesday, 20 May, and with public access restricted to ensure safety, the Plett Stranding Network made the difficult decision to proceed with humane euthanasia.  The operation was led by SAPS bomb squad expert Johan Ehlers, who has extensive experience in large mammal euthanasia.  “While deeply distressing, this was the kindest option to prevent further suffering,” said Visser.  “Drug injections are not viable for whales due to their physiology.  Explosives remain the most humane method.”

The euthanasia was carried out successfully and the whale will contribute to scientific knowledge and conservation efforts.  Blubber and muscle samples have been collected for further research, and additional data will be gathered to support long-term monitoring of whale health, disease, reproduction, and threats in the marine environment.  The carcass will be towed out to deep sea for disposal within the next week.  “This incident, while heart-breaking, showed the incredible collaboration and resilience of our network,” said Visser.  “We've learned valuable lessons and grown both professionally and personally.”

(Article shortened: Hardus Botha)

General Manager: Advocacy

Petro van Rhyn

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