Commercial whaling has had a devastating impact on the Oceania whale population, with fewer than 5% remaining. Now, the tohoraha (humpback whales) are returning to Rangitāhua, and we're thrilled to see more and more with each voyage made to the Kermadec region. 

Blog by Rochelle Constantine, conservation biologist and behavioural ecologist.

The whales use these waters as a stop-over point after leaving the Pacific Island breeding grounds, staying for around four days before they continue their long journey south to Antarctic waters. The peak stop over time is mid-September to mid-October, so our Te Mana o Rangitahua voyage was nearing the end of last year’s season. But we were really pleased to still see whales coming through, mostly mothers with their new-born calves who are only a few months old but already able to leap clear of the water and play with other calves.  

Playful whale showing its head and tail

We use the underside of their flukes (tail) to identify individual whales. Over the 10 days we spent in the small research boat, we identified 37 different adult whales. We also collected nine skin samples from whales. When they launched their bodies out of the water and splashed down on the sea surface, tiny little bits of skin fell off. We gathered these to do genetic analysis.

Whale flukes at Rangitāhua

One big difference from our earlier research visits is that there were very few singing males. We suspect that they have already passed the islands and now we’re seeing the mothers with their young calves who need to swim a little slower and take the time to let their calf grow as they swim south.  

We came so close to losing the tohoraha with commercial whaling leaving fewer than 5% of the pre-whaling numbers. But they are recovering, and Rangitāhua is an important place for them to gather. 

Jaynie Lelievre and Rochelle Constantine capturing data for whale surveying

All whale work was performed with Ngāti Kuri permits.

Rangitāhua expedition

Explore the full series of blogs from the Rangitāhua voyage.