Whales - Facts | Migration

Whale - Migration

Whales, as an entire species, embark on migratory movements for a variety of reasons. These reasons include changes in the seasons and the temperature, depth, salinity and landscape of the ocean floor. The major reason for these seasonal movements, however, is the availability of food. It can generally be said that whales travel to colder waters to feed and build their blubber supply. During their calving seasons, they move to the warm waters and give birth in these more temperate conditions.

Baleen whales include well-known mammals, such as the Humpback Whale, the Southern Right Whale, and the Blue Whale. As a family, they are found in all the oceans of the world. For this reason, it seems strange that they would all still choose to migrate to other areas during the course of the year, but they continue to embark on these extensive trips. However, most species of whale are hesitant to cross the equator, so there do tend to be species peculiar to the northern and southern hemispheres, e.g. the Southern Right Whale and the Northern Right Whale.

Migration is closely associated with the reproduction habits and requirements of the whale. Because the gestation period of most whales extends for approximately one year, females are able to mate in warm waters, and then give birth in these same waters the next time they migrate to this area. In the period between the mating and the birth, she is in the cold waters that provide an abundance of food to keep her and her calf well-fed and healthy. It also assists in building up the energy required to feed the calf until it is ready to be weaned.

Over the years, many whales and their migratory patterns have been tracked using the distinctive markings on their tails. This requires an extensive amount of research, studying, administration and recording. Because of the labour-intensive nature of this tracking, scientists now tend to prefer satellite tags. These tags are embedded into the flesh of the whale by using a crossbow and shooting the cigar-sized radio transmitter into the whale. These transmitters then communicate with satellites, providing vital information regarding the type of whales migrating, the areas they frequent, the routes they follow, and the duration of their stay.

In South Africa, the seaside village of Hermanus is a popular whale-watching destination, as densely populated pods frequently make their appearance along the coastline. The Western Cape is the southernmost part of Africa and is the point where the warm Indian Ocean meets the cold Atlantic. As such, it experiences some of the most varied and fulfilling whale watching in the world. Whales come to this area between June and November, usually give birth and to nurse their new calves.

South Africa boasts at least 37 species of whale swimming off its coastline. The “Whale Route” stretches from Cape Town to Durban, some 1200 miles. The Southern Right Whale and the Humpback Whale are particularly pervasive in the South African waters, and are often spotted just metres from the shoreline, although Bryde’s Whales are also common in the slightly deeper waters.