HUMPBACKS BREAKING THE RULES in ALGOA BAY
By Jake Keeton

Sunday, 6th February 2022

During our last five consecutive cruises out to St Croix island we have sighted the same two sub-adult Humpback Whales. The last sighting was one of the most spectacular with the larger of the two individuals launching itself into the air in a series of breaches. It appears that the pair have decided to make the Bay their home for a few extra months. Each time we have found the pair they have been milling around in the shallows, never more than a few miles from shore with all of the last five sightings being within an area of about five square miles, just offshore from Blue Water Bay. A few characteristics of these sightings have led to some interesting questions and discussions with guests on board. Statements like; "I THOUGHT IT WASN’T WHALE SEASON AT THE MOMENT" and "AREN’T ALL THE HUMPBACKS SUPPOSED TO BE FEEDING IN THE SOUTH SEAS RIGHT NOW?" have been a daily occurrence. Our reply to our guests is that we do not know for sure why these two individuals have decided to stay in our Bay for such a long time, and specifically in such a small area within the Bay. It could be that they had a run in with killer whales and do not feel safe to venture back out into deeper water. Another theory is that they have found a food source in the Bay and have chosen to stay and feed here rather than make the long swim back to the icy waters of the South Seas.

Typically, we are supposed to see Humpback Whales (Megaptera novaeangliae) in our waters from June through to December each year as they make their Northerly migration. The reasons these whales undergo this massive 5000 mile migration is to feed, have calves and mate. Humpback whales migrate from their summer feeding grounds in the South Seas to their winter breeding grounds in the warm waters around the equator. The whales normally hit the South African Coast in late May/Early June. Some then make their way up the West Coast and the rest up the East Coast. Their mission is to get to the warm waters near the Equator to birth their calves, then once the calves are strong enough, they escort them back to their summer feeding grounds in the South Seas. Calves are born with little insulation to keep them warm, thus the warmer waters around the equator are essential for their survival. Males make this long migration to mate with the receptive females in the warm waters. With the gestation period for Humpback Whales being roughly eleven months, for the calves to be born in the warm waters between July and October they need to mate here during this time.

New-born Humpback calves are between 3.9 and 4.5 meters in length. The calves grow extremely fast as the milk they get from mom is made up of 42% water 9% protein and a whopping 43% fat and 2% ash. This high fat content causes the calves to grow at a rapid rate as well as build up a thick layer of blubber to keep them warm when they return to the South Seas. Lactation lasts about eleven months and calves are normally weened when they are between 8 and 10 meters in length.

Humpback Whales rely on the richness of their summer feeding grounds in the South Seas to enable them to undergo their massive Northerly migration to reproduce. It is vital that they are able to build up a large amount of body fat as a store of energy to last them may right through to December. Luckily for the whales there is still plenty of food to go around. In the South Seas during the Summer months, you have plenty of sunlight and cold nutrient rich water, the perfect recipe for Phyto Plankton to bloom. These plankton blooms are so large they can be observed from Space. All these microscopic plants are food for Zooplankton Such as Krill. With an abundance of food, the krill quickly multiply forming giant swarms which the whales can easily feed on. Humpback Whales also feed on fish such as herring and sardines if given the opportunity.

Humpback Whales are a great success story about the power of collective thinking. After being hunted to near extinction, their population has bounced back to what it was before whaling ever started. People all around the world simply decided to stop hunting whales and to protect them instead (There is no reason why we cannot do the same with the production of single use plastics). Some people voice concerns about how there could be too many whales and not enough food for them since whaling has stopped. The truth is that whales create their own food. Their movements bring cold nutrient rich water closer to the surface where it reaches the sunlight, this caused Phyto plankton to bloom. Their waste also acts as a fertiliser. Scientists estimate the between 50% and 80% of the oxygen we breath comes from the Ocean, specifically from Phytoplankton and other Aquatic Plants. The abundance of whales is directly linked to the health of our Oceans and our Planet as a whole. If we make sure the whales thrive, we can thrive.