The wind-whitened peaks of ocean swells pitch the boat furiously as Sir Peter Markham Scott shifts his sneakers in search of firmer footing and scans the horizon.
Suddenly, a sighting just off the starboard bow: aquamarine triangles made by the white pectoral flippers of three humpback whales gliding just beneath the surface. At last, the first long, black back slowly arches above the salt spray.
''There they are, straight on!'' shouts the conservationist, his voice sparked by excitement as he scurries around the wheelhouse in search of his wife - and her camera.
They get back to the forward rail in time to watch the humpback trio, rising and receding in a rhythmic harmony of massive motion, finally flicking up tail flukes, a signal for a deep dive.
As one of the world's foremost conservationists, and chairman and founder of the World Wildlife Fund International, Sir Peter counts humpbacks among his favorite acquaintances. So he's eager for today's expedition to Stellwagen Bank, a gray-green expanse of ocean some 25 miles off the New England coast - a summertime playground for whales.
Several years ago he and Lady Scott swam among the giant cetaceans in more human-hospitable waters near Hawaii, along with scientists studying the creatures.
''The nearest we came was with an animal's eye about 20 feet away,'' says Sir Peter, suddenly animated by the reminiscence. Pointing upward, cocking his head slightly, he re-creates the slow shift of the whale's gaze as it went from one swimmer to another.
''I would have given a great deal to know what was going through that animal's brain just then,'' he adds, his smile melting into a rumbling chuckle. Then, just as smoothly, Sir Peter's mood becomes serious as the conversation turns toward efforts to preserve ocean mammals - one of his special interests.
''Many people now regard them [whales] as a symbol,'' he says. ''If we can't save the whales, then we begin to wonder if we will be able to save anything - including ourselves.''
Knighted by Queen Elizabeth in 1973 for his service to the crown in the field of conservation, Sir Peter's formal accomplishments soak up over half a column of small type in the British Who's Who. Included is the fact that he's a bronze-medal-winning Olympic sailor (1936) and was Britain's national gliding champion in 1963.
He is the quintessential conservationist: warm and wondering about the natural world, yet savvy when it comes to the international politics and economics intertwined with large-scale efforts at wildlife preservation.
He knows, for example, that Westerners must tread lightly when stumping for conservation in the underdeveloped world.
''Conservation has got to be couched in such a way that it becomes acceptable to the local culture and illustrated by examples familiar to everyone,'' he says. In some areas conservation is mistaken as another intrusion of developed nations into the affairs of less-developed countries, instead of being a subject everyone can take part in, he says.
In Brazil, for instance, the accumulation of silt in rivers has been linked by conservationists to the thousands of acres of tropical rain forest in that country which are cleared every year for agriculture and development. This has caused international concern, not only because of the impact on the local environment, but also because of possible long-term influence on the earth's climate. Some scientists believe temperature patterns could change as a result of the clearing - with possible detrimental impacts worldwide.
Efforts to stop the clearing have been resisted by Brazilian officials, who interpret it as outside interference aimed at hampering development. But, says Sir Peter, Brazil is one of the countries in which conservation seems to be catching on.
''The government is suddenly saying, 'Oh, yes, we'd better pull in our horns on clear-felling the forests and do things a bit more sensibly.' ''
While focusing much of his attention on third-world nations, the scuba-diving septuagenarian has been a driving force behind the drafting and signing of several major conservation treaties.
Among other things, he helped promote an international agreement protecting polar bears and another aimed at stemming illegal trade in endangered plants and animals.
But Sir Peter says the high point of his career was the launching of the World Conservation Strategy in 1980 - a wide-ranging program designed by the International Union for Conservation of Nature and Natural Resources with the help of the WWF and the United Nations Environment Program.
The strategy establishes a framework for national conservation efforts, identifying the most significant environmental issues and proposing government actions. So far, 35 nations have agreed to support the strategy, including Belize, Spain, and New Zealand.
According to Sir Peter, the strategy is more than just a lofty-sounding bundle of glossy pages. In some cases, countries even receive some financial support from the World Wildlife Fund to get the environmental ball rolling. Most of the work is still in the formulating-strategies-in-order-to-write-strategies stage.
The strategy explains that any kind of lasting prosperity requires care to be taken about the environment,'' Sir Peter says. ''By the same token, you cannot get enough money for conservation unless you have development - so the two are interdependent.''
This sort of realism is a trademark of Sir Peter's style of conservation.
''I think conservation - and certainly the World Wildlife Fund - has gone past the extreme protectionist view,'' he says. ''I do recognize there are legitimate reasons for people to kill animals, not only to eat, but to safeguard their flocks and themselves.''
Sir Peter also recognizes the need to sometimes control the number of wild animals to keep them from overpopulating and damaging their own habitats. This is especially true in regions where natural predators have been eliminated.
While some may consider such ideas environmental blasphemy, it's a view gaining ground among a number of conservationists. In parts of Africa, for example, it's easier to squelch poaching when the government agrees to let local residents selectively hunt - or cull - a certain number of animals per year.
Besides his work as a conservationist, Sir Peter is also an artist, specializing in delicate renderings of waterfowl - swans, ducks, and geese. In the 1950s, his artistic realm expanded when he discovered the beauty of underwater coral reefs and fishes.
Describing his first glimpse of this watery world - with a cheap borrowed mask on a trip to Australia - he says, ''It was the most beautiful thing I'd ever seen, as a naturalist, as a painter, or as an artist.''
According to his wife, there is seldom a moment when Sir Peter's thoughts are not focused on some aspect of natural history. ''If he has a one-hour layover in an airport,'' says Lady Scott, ''he'll get a glass of water and do some watercolors of birds or fishes.'' He carries a small paint set for just such occasions.
When he goes diving among the brightly colored angelfish and jagged coral heads, Sir Peter carries a small, white-formica drawing board. Two ordinary lead pencils attached to the board by string are used to sketch pictures and list species spotted.
The system seems quite effective, all the way down to the pencil eraser, which, he says, ''works much better underwater than it ever does on dry land - it just wipes it straight away.''
In describing his aquatic note pad, the animated storyteller once again takes over. Where, he asks, might one expect the pencils to hang while underwater?
''Not dangling down here,'' he says, fluttering fingers below a book he has snatched as a prop. They float up above, he says, waving his hand as he might 25 feet underwater on Australia's Great Barrier Reef.
''The only drawback is that if anybody gets their mucky fingers on the board after you come up, it smudges.'' To avoid that, he photocopies the drawing board after every dive and enters the page in the diary he keeps on every field expedition.
Sir Peter has compiled over 50 field diaries, containing everything from lecture notes to watercolor paintings of birds and fishes. Some of these diaries will soon be published in England under the title ''Travel Diaries of a Naturalist.''
In addition, he's the author of 14 books and illustrator of another 17. Three of his books were done in collaboration with his wife, Lady Scott, who proudly proclaims herself to be the professional photographer in the family. They work as a team.
''I wouldn't let him take serious photographs,'' says Lady Scott. ''Of course , I could never remember all the scientific names for the reef fishes that he can. . . .''
Amid these activities, what does Sir Peter see happening in the natural world he holds so dear? Are we becoming more enlightened in how we treat our earth? Less abusive, perhaps?
According to Sir Peter, who began conservation work in the 1930s, there are hopeful signs: Countries such as Kenya and Zambia, for instance, have done a great deal to develop large wildlife clubs which bring in tourists - and badly needed foreign exchange - while preserving habitats.
At the same time, species such as the Hawaiian goose and the vicuna of South America (a diminutive relative of the llama), have been brought back from the brink of extinction through conservation efforts.
''That isn't to say that we haven't got an awful long way to go - we undoubtedly have,'' says Sir Peter. ''That's why I say that our most important task is to make people more aware through education, and that goes all the way from leaders down to the children.''
Much of Sir Peter's work in education has been done through the Wildfowl Trust, which he established in 1946.
The trust now has seven educational centers scattered across Great Britain, including the Slimbridge headquarters, which encompasses 4,000 acres of wetlands. The original idea was to establish an ''ark'' where endangered species of waterfowl could be maintained in the hope of one day reintroducing them into the wild.
Part of the reason for Sir Peter's success can only be described as ''good connections.''
Son of the Antarctic explorer, Capt. Robert Scott, who perished in his unsuccessful bid to be the first to the South Pole, Sir Peter grew up knowing about life in the limelight. This helped him to develop valuable ties to members of the royal family. Prince Charles, for example, is president of the Wildfowl Trust.
Meanwhile, Sir Peter says there are plenty of other things he wants to do in the next few years. Not the least of which, of course, is swimming with sperm whales, or possibly blue whales. All in good time.