The Largest Humpback Migration to Date?

By Raggy Charters. All images by Lloyd Edwards of Raggy Charters

What incredible cruises we have been having lately, the Humpback whales just never seem to end! We were out yesterday and spotted three humpback cow/calf pairs near the Bell Buoy in Algoa Bay. After spending our allotted 20 minutes in the area looking for them, they had simply vanished into thin sea! When this happens, it is much better to move on as it seemed that they did not want to be disturbed.

Then we saw some splashing off Cape Recife and heading towards the action. When we arrived, we observed two cow/calf pairs, both of the calves tail slapping. They need to build up their muscle control for the rest of the 2000km journey to their feeding grounds. While in neutral at our permitted distance, the two large females with their calves in tow headed straight towards us without any warning. Everyone on the boat froze as they carried on towards us and arched their backs and dived beneath the boat. We were spellbound! What an absolutely amazing experience. After that encounter we saw another twenty or so around the bay. One of the calves was so happy to see us that it breached 32 times in a row!

We have seen so many Humpback whales this season that everyone is saying that this is the largest one on record. What does science tell us?

Chis Wilkinson, who was the lead author in a scientific paper published in the African Journal of Marine Science entitled “Estimating population changes in humpback whales migrating past Cape Vidal in South Africa” had the following to say.

In 2018, approximately 10 498 humpback whales passed Cape Vidal in KwaZulu Natal on their northward migration from the 27th June until the 6th August. In 2019 11009 passed during the same period. It is estimated that the annual that there is between a 7,4% to 8,8% increase over 31 years from 1988 to 2018/2019. These results indicate a slowing of the increase from previous estimates which would suggest that the population is approaching pre-exploitation numbers, OR that as yet unidentified threats are negatively impacting the growth rate”.

Since the humpback population was protected from commercial whaling in 1963, it has increased steadily. If we assume that the population was growing at 7% per annum, it means that at present there should be around14 400 of these amazing animals passing Algoa Bay on the southward migration. Most of the males, juveniles and newly pregnant females have already passed us while the cow/calf pairs are bringing up the rear.