An annual survey of humpback whales in Cook Strait has begun, with former whalers and the Department of Conservation on watch in the Marlborough Sounds.
The four-week watch is assessing humpback recovery since commercial whaling ended in New Zealand in 1964.
A group of ex-whalers will be looking for tell-tale water spouts.
A DoC boat then heads out to photograph the whales and take skin samples, using a biopsy dart.
Thirty-seven humpbacks were spotted in Cook Strait last year and DoC says that's only a fifth of the number seen in 1960.