Facts and Information on Southern Right Whales
Southern Right Whales are the main species of whales visiting the shores of Hermanus although Brydes whales are found in Walker Bay all year and Humpback Whales migrate off shore of the bay during June, July and sometimes as late as August.
Studies indicate that the Southern Right whale population was reduced to no more than 10 - 40 adult females when commercial whaling was stopped off our shores in 1935.
When aerial surveys of Walker Bay start in July every year, there are about 50 whales in the bay. This increases to 200 at peak whale watching season in September and October.
The 2011 total population in our waters was estimated at about 3500.
As early as 1770, whalers from the USA, Britain and later France were working our waters and took up to 18 000 whales a decade. The depletion of the population was rapid as the movement of whales was so predictable and even with the primitive equipment used by open boat whalers, the slaughter was efficient.
Southern Right Whales were so named because they were the “right” whale to hunt. These whales were easy to spot, were rich in baleen and oil, and floated when shot, thus making it easy for a boat to tow the body to a processing harbour.
Since 1969 aerial surveys of the movement of whales have been carried out and the results of these studies have given scientists a clearer picture of the movement and habits of the whales.
Some of the observations are:
- White calves rarely return with a calf, therefore scientists believe most white calves are male
- The majority of cows calve at three year intervals but the interval can be 6 - 7 years
- Calves have returned with their own calf indicating the age at which whales reach sexual maturity - from as young as 6 years but most seem to calve at 10 years for the first time
- Calves are between 4,5m and 7,5m at birth and weigh in at around 1 tonne
- Calves grow at a rate of 2,8cm a day and increase in weight of 75kg per day
- Gestation is about one year
- Calves are generally born between July and November
- Information from stranded whales indicate that most mortalities are the first born calf
- Whales are long lived and could reach 100 years in age
- The birth of a whale is unspectacular and usually carried out in isolation. A cow will rapidly drop her calf out at sea and then move into a bay
- Whales mate at all times of the year and when a large group of whales is seen interacting in the water it is most likely a mating session
- Several males will vie for a single female
- Being non-aggressive the whale male contests for a female by sheer size of testes and quantity of sperm