Eavesdropping on Whales by Clive Tully

"He must know we have the paparazzi on board," muses Lisa Steiner as the massive bulk of a sperm whale cruises gracefully across the bow of our boat. "It's not often one shows you his best side."

It's a rare moment for whale-watchers, since most encounters involve coming up on whales from behind, ending with the classic display of the tail, or fluke, before these intriguing giants of the deep disappear beneath the waves to return to their feeding.

But this close encounter with sixty tons of sperm whale is no fluke, if you'll pardon the pun. While local whalewatch companies in the Azores rely on land-based lookouts, the 68ft staysail schooner Colomban is equipped with a hydrophone which, when trailed in the water, picks up the characteristic clicks made by sperm whales when they're feeding. Because of this, the vessel has a 100 per cent success rate for sperm whale sightings.

The Colomban can accommodate up to eight passengers, and each is invited to take a turn on watch, listening on headphones every 20 minutes. The hydrophone has a range of seven miles, and can even detect which direction the whales are heading. For a while all we hear is the rushing, gurgling sound of the water going by, then Shropshire midwife Helen Buckle's face lights up. "I can hear them," she says. "They're clicking away like mad."

By the end of the day, we've seen sperm whales lobtailing - slapping the water with their tails - and a number of breaches, where they launch themselves from the water, falling back with an enormous splash.

Wherever whales congregate, you'll find companies offering whale watching tours. The big difference in the Azores is that I'm with a specialist tour operator which not only offers a much better chance of sighting whales, but involves you in scientific research as well.

American marine biologist Lisa Steiner worked in the Azores for several years on the International Fund for Animal Welfare boat "Song of the Whale". There she met and married Englishman Chris Beer, and they set up Whale Watch Azores, operating from Horta on the "blue" island of Faial.

Logging all the whale encounters is just one way clients can help the research. Whenever a whale is sighted, Lisa photographs it. The nicks and notches in the fluke and dorsal fin help with identification, and the photos go into a photo ID catalogue which helps determine population size and migration patterns. Since IFAW finished their programme in the early 90's, Whale Watch Azores has doubled the size of the catalogue. They also sponsor students.

Regulations ensure whales aren't stressed by encounters with boats. They should only be approached from behind, and boats should go no closer than 50 metres.

Chris now wants to establish a network of hydrophones at strategic points around the island.

"It would mean we could determine more accurately where the whales are," he explains. "By sharing the information amongst all the whale watching companies, we can lessen the impact on the whales by spreading the boats out. It's better for the clients, too."

Such a project will require significant funding, but Lisa and Chris are already testing a prototype hydrophone.

Apart from the whales, it's a certainty you'll see dolphins galore. All pretensions of adulthood vanish as I dangle my legs down either side of the Colomban’s bowsprit, whooping with delight as I gaze straight down on a group of bow-riding bottlenose dolphins.

There’s plenty to see on Horta, a lush volcanic island, on the days you’re not at sea, and while untarnished by commercialism, it is extremely cosmopolitan, and the traditional stopover for transatlantic sailors. Just above the harbour is the bar they all make for - Peter's Cafe, where the walls are decorated with memorabilia left by visiting yachtsman.

There's also a fascinating museum of scrimshaw - the incredibly intricate etchings on whales' teeth started by whalers of old. The art survives to this day, but don't bother buying any - importing scrimshaw into the UK is illegal.