A SALTY character who in far-off times, had sailed the South Seas, dined with cannibals and dallied with Samoan maidens, Dennis Puleston also has a niche in the annals of conservation for the campaign he led against the pesticide DDT in the United States after demonstrating its devastating effect on the osprey population of Long Island.

Always a keen amateur ornithologist, the English-born Puleston became puzzled, in 1966, by the marked decline in hatchings of osprey chicks at the Long Island site where he was used to observing them. After examining several nests where promising clutches of eggs had failed to produce the expected broods, he discovered that the local health authority’s use of a DDT spray to suppress the mosquito population was weakening the shells of the osprey eggs and causing the death of the chicks inside.

With like-minded spirits living locally, he banded together to sue the local authority and succeeded in having a halt called to the spraying. During the bringing of the action it was his exquisite watercolour paintings, which depicted the food chain from plankton to the fish and crabs that preyed on them and thence to the fish-eating eagles, which convinced the judge of the rectitude of the environmentalists’ cause. DDT was banned locally in 1967 and by 1972 its use had been made illegal across America.

Dennis Puleston was born in Leigh-on-Sea, Essex, in 1905, and nurtured by the Thames estuary and its pageant of passing ships. Messing about in boats was in his blood at an early age and he also became a keen observer of the birds of the Essex mudflats. He studied biology and naval architecture at London University, but before he could convert these assets into a steady career he was seized by the lure of a sea adventure. In 1931 he set sail for the West Indies with a chosen shipmate in the 31ft yawl Uldra. It was the beginning of a somewhat haphazard but nevertheless absorbing saga, which included, en route, an attempt — not totally unsuccessful — to develop a derelict coconut plantation in the Caribbean. Eventually the pair left their craft there and shipped aboard the schooner Pinta as deckhands for the passage up the American coast. This ended in shipwreck on Cape Hatteras.

Nothing daunted, Puleston next joined forces with another man who was fitting out a 75ft ex-Newfoundland fishing schooner, Marit, for an expedition to salvage an alleged cache of sunken treasure off Santo Domingo. At the time, Marit was in Newfoundland where she was in imminent danger of being frozen in for the winter. Hastening north with his new shipmate, Puleston managed to get the schooner to safety before the ice made it impossible and the pair set off for the West Indies. There they sighted coral-encrusted cannon aplenty on the seabed, but the treasure remained — as treasure is apt to — elusive.

Nevertheless, another adventure awaited. Puleston joined forces with two brothers who were about to set off for New Guinea in a Portland, Maine, pilot schooner, the Director. This led to a two years’ cruise in the Pacific, which involved many brushes with local native populations on what were then remote South Sea islands: the Marquesas, the Society group, the Solomons and Timor. On one occasion Director and her crew were arrested in the name of Queen Wilhelmina of The Netherlands by the suspicious inhabitants of a small Dutch East Indies island.

Malaria eventually put an end to this tropical sojourn, and in 1937 Puleston made his way alone to China. There, however, the Sino-Japanese War rendered irrelevant any entrepreneurial plans he might have had and he decided to return to Britain, eventually reaching London after a long journey on the trans-Siberian railway.

The colourful account of these adventures, Blue Water Vagabond, was published in England and America in 1939, and was a big popular success, reprinted several times in the subsequent decades. Puleston returned to America where he settled in New York and married his wife, Betty, becoming at the same time an American citizen.

When war broke out his experience as a naval architect was soon put to good use. Among wartime projects on which he worked was the DUKW (always known simply as the "duck") a useful amphibious transport and troop-landing vehicle which was widely used in the Far East theatre. Puleston was sent out to the Pacific to train American troops in its use, and also established a training school for the British in India.

During amphibious operations in the Solomons he was badly wounded in the spine by a Japanese shell splinter. But after a period in hospital he recovered sufficiently from his wounds to be able to come to Britain to train troops to use the DUKW for the Normandy landings. Thereafter he returned to the Pacific to set up a DUKW training school on the Hawaiian island of Oahu, afterwards accompanying the American landings on Iwo Jima and Okinawa. He was awarded the Medal of Freedom by President Truman in 1948 for his war services.

He next joined the Brookhaven National Laboratory on Long Island, working there as director of technical information until his retirement in 1970. After his victory in the osprey case, he founded the Environmental Defence Fund, which grew to a membership of 30,000 and enlisted specialists from the worlds of science, the law and politics to carry on its fight against environmental pollution.

Even after his retirement from the BNL Puleston kept himself active, beginning a second career as a lecturer and guide accompanying tour parties to remote parts of the world. Among the more than 200 cruises he accompanied were 35 to Antarctica, one of his favourite regions of the earth. In retirement Puleston published a second book, A Nature Journal: A Naturalist’s Year on Long Island. Illustrated by 155 of his watercolours of birds, animals and plants, it appeared in 1992.

Thanks to package tour travel, the world had by then become a smaller and less mysterious place than that which he had sailed and explored in the 1930s. Puleston loved to reminisce about those times and the freedom from routine and convention which they conferred on him and his shipmates. Of Samoan maidens, in particular, he was prone fondly to recall: "Remember the local virgins? These beautiful Polynesian maidens with those undulating arms kept serving that kava . . . from the waist down you’re just paralysed . . . the kava had done its work, and the next morning the local virgins were still the local virgins."

Puleston is survived by his wife Betty, and by a son and two daughters.

Reprinted from the London Times 21 June 2001