Image courtesy Dr Alison Kock.
Image courtesy Dr Alison Kock.
  • Large super-groups of Humpback whale, reaching as many as 150 per group, are gathering off Dassen Island, some 45 kilometres South of Saldanha Bay. 
  • Some estimate that as many as 600 aggregate here before making their way to Cape Point as part of their annual migration from polar summer feeding grounds to winter calving and nursery grounds.
  • Authorities are urging ships to steer at least 300 metres clear of the massive groups in order to prevent ‘vessel strikes’ - unless you have a permit. 
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Large super-groups of Humpback whales, reaching as many as 150 per group, are gathering off Dassen Island, some 45 kilometres south of Saldanha Bay.

There could be as many as 600 of the whales aggregating here, before making their way to Cape Point as part of their migration from polar summer feeding grounds to winter calving and nursery grounds.

With the increased attention they are getting, authorities are urging ships entering and exiting the harbours of Cape Town (about 5km away) as well as Saldanha Bay to steer at least 300 metres clear of the massive groups. 

“We’re asking tour operators who are not necessarily permitted to get up close to whales, like unauthorised tourism vessels and fishing boats, not to approach the whales closer than 300 metres,” said Mduduzi Seakamela, Department of Environment, Forestry and Fisheries (DEFF) marine mammal biologist.

Seakamela is fresh off the back of a survey of this special aggregation point which happens nowhere else in the world. The survey included a sea rescue where one whale had to be disentangled from fishing gear, something that he says is occurring more frequently. 

“There is something spiritual when a whale is looking at you. I don’t know what it is but to stare into a whale’s eye, your spirit is cleansed. It's something ritual and divine.”

The risk has been reported to the South African Maritime Safety Authority (SAMSA) as well as the National Oceans and Coastal Information Management System (OCIMS) which brings together a party of stakeholders in the marine economy under a single coastal management system and integrates ships movement. 

Image courtesy Dr Alison Kock.
Image courtesy Dr Alison Kock.
Image courtesy Dr Alison Kock.
Image courtesy Dr Alison Kock.

Ship strikes pose a very real threat to whales said Alexander Vogel, a developer of the app Seafari that allows users to log sightings of marine mammals anywhere in the world, including those watching the Humpback whale super-groups. The free platform is used to document marine mammal sightings and give access to citizen science data. 

“Ships that are docking in Cape Town or Saldanha Bay are the problem as they will pass through the super-group locations. Ship speeds above 10 knots are invariably fatal if a whale is struck. Smaller vessels are also a threat as the higher speed will make up for the lower weight and cause potentially serious injury or death.” said Vogel.

In 2018 Vogel saw a coastal freighter race at 18 knots, recorded on an app called MarineTraffic, directly towards a super-group off Hout Bay.  

Regulating marine traffic in the areas where this aggregation point is, is tricky. The whale groups are fluid and branch out, and some will stay in the area for months at a time, said Vogel.  And unlike other known aggregation sites of whale, like in North America where speed and safe zones are starting to be regulated, it is difficult to negotiate designated protection zones with stakeholders because the whales routes are unpredictable, said Seakamela.

"Our Blue Economic activity is fairly lower than other nations. The Northern Right Whale is a high ship traffic zone. At one point there were few of these whales left. That’s why they had to intervene with vessel restrictions." 

*Video footage kindly supplied by DEFF.

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