Humpbacks visit St Croix Island
By Lloyd Edwards

1. News

As per our previous posts, we are still experiencing the largest humpback Southern migration in 30 years and arguably the largest since whaling commenced in our waters in 1908. I have tried for many years in vain to get some great images of humpbacks breaching with St Croix Island in the background. Myself and Lorien Pichegru spent many nights in the houses on St Croix studying the foraging habits of the African penguins. To see the once flourishing colony almost destroyed by ship to ship fuel transfers and overfishing is heart wrenching believe me. I guess 2023 was my year for images, thanks to my skippers Jake Keeton and Keith Gibbs.

In order to be able to breach, humpback whales need to reach a velocity of 29km/h. They do this by swimming parallel to the surface and then change to vertical once this speed has been reached. The last movement is an almighty beat of the tail flukes. The energy used in this maneuver is equivalent to 40 hand grenades!

While adults seem to breach either for having fun, assisting in communication, defense or getting rid of parasites, I think this maybe different in the calves. Most of the calves in the images were probably born off East Africa around three months ago. They are now between eight and ten metres in length. I think they breach in order to get their muscles into shape for the long swim back to their feeding grounds some 2000km to the south. Being able to pull off a good breach may indicate to the mother that her calf is ready to take on ship strikes and marauding killer whales. We wish our new born calves bon voyage!

A humpback calf launches itself into the breach just off St Croix Island. Taken with a Nikon D810 full frame, ISO 1000, 200mm zoom, f/10 and 1/1250th second.

This adult launches into the breach just off St Croix Island facing facing Hough Park in Algoa Bay. Note the extremely long pectoral fins, the largest appendage of any animal. They are used for swatting killer whales that try and prey on her calf.

This calf is busy re-entering the water after a massive breach. Note the rounded and raised tubercles which correspond to the positions of rudimentary hairs. They are thought to assist during feeding.

This calf is starting it's breach on the North Western part of St Croix Island. Note Diaz's cross just in front of the head and the guano collectors house to the right of the image. Lorien Pichegru and I spent many nights there monitoring the foraging habits of African penguins.

Note quite a full breach but a behaviour known as "spy hopping". Whales can see out of the water and was probably taking a closer look at us.

Another great breach off the South Western side of St Croix Island. Note the infestation of barnacles on the skin. These tropical crustaceans will fall off when the animal reaches the 2 degree water in the sub-Antarctic.