Whalers almost wiped out the southern rights in a decade of slaughter. Since then they have rarely been seen.

After 150 years of near-extinction, a lost tribe of great whales has resurfaced. The discovery of their remote breeding grounds at mysterious islands in the subantarctic has sparked new hope for their survival.

Researchers and film-makers set sail in the sturdy yacht Evohe, heading out from New Zealand into the the wild seas of the Southern Ocean to reveal the secrets of the lost whales and film their most intimate moments.

They brave winter to rendezvous with the gentle giants in a huge natural harbour sheltered from the furious storms which sweep across the islands from the Antarctic.

After a history of massacre, the researchers wonder how the whales will react to their presence in the breeding grounds. But far from being fearful of humans, a curious whale comes alongside the Evohe to investigate the newcomers.

It’s the start of a winter of wonder with the whales. The dive team builds a relationship with several of the whales, being entertained with an underwater ballet ending in a spectacular aerial display; a teenage tantrum which gets a little too close for comfort; a protective mother caring for her new calf; a hectic game of chase with tormenting sea-lions;  and a play session in the seaweed forests.

Researchers identify whales and begin a modern whale hunt—for knowledge. Armed only with a small crossbow, they take skin and blubber samples to learn about pollution levels, family relationships, and possible connections with other groups of whales elsewhere in the world. It’s feared that these whales may have been reduced to such a low number that any population recovery will suffer from in-breeding—reducing their chances of long-term survival.

But these remote islands are full of survivors—the world’s rarest penguin, the rare New Zealand sea-lion, and a host of birds and plants which have been blown here from distant lands by the tempestuous winds. All have adapted to thrive in their new home. Despite the bleakness of the islands, they are one of very few places where the creatures of the Southern Ocean can find somewhere to breed and raise a family.

Breeding is why the whales are here. They’re getting down to serious courting, with prolonged foreplay and astounding matings in the clear cold waters of the bay.

The giant lovers take their time, at first a couple, and then a group, all so intent on each other that they ignore the divers recording the greatest love scene in the animal kingdom.

Away from the main action the divers are amazed when a mother allows them close to her new-born calf—the closest anyone has got to filming a birth, which has never been seen. Researchers report that this population of Southern Rights is growing, but its future is still in question. They plan to return next year.

As winter ends it is time for whales and researchers to leave the islands. The yacht Evohe follows familiar friends into the Southern Ocean, heading for the freedom of the open seas.