Tohorā – southern right whales
Southern right whales are the curious, gentle giants of the whale world. Don’t let their huge size – up to 18 m and 80 tonnes – fool you – they often approach and inspect things in the water, can launch themselves out of the water, and even play with kelp. Their curiosity and gentleness meant that they were the target of early whalers, with over 150,000 killed between 1790 and 1980 worldwide. Whalers gave them their name – they were the ‘right whales’ to hunt because they are slow, float when dead and yield a lot of oil and baleen. Image: Richard Robinson, Depth NZ, taken under DOC permit.
New Zealand southern right whales – tohorā nō Aotearoa were abundant in Aotearoa New Zealand before whaling. However, the hunt drove the population to as few as 40 individuals around 1920 from around 30,000 before whaling. Remarkably, the population rebounded to around 2000 tohorā in 2009.
The remarkable recovery is driven by amazing mums. Southern right whales have one calf about every three years. The babies are 4-5 m long when born, and grow up to 1 m per month. As mum is fasting on these wintering grounds, she loses about 25% of her body size in the first few months of nursing her calf.
Southern right whales – tohorā are a migratory species, moving between summer feeding and winter socialising and nursery grounds. Today, they can be found in winter months primarily in the Auckland Islands Maungahuka, which is the only nursery ground for the species left in Aotearoa New Zealand, and Campbell Island Motu Ihupuku, which seems to be a bit of a hang out spot for juvenile whales. The mainland – North and South Islands – are also areas where the tohorā can occasionally be seen in winter, and is used by mums and calfs, and socialising whales. However, where the whales go during summer, and how they get there, is what we are trying to find out more about.