PORTLAND, Maine -- The seal population is exploding off the Maine coast, with the greatest surge coming in the last decade.
"At least to the back of the turn of the last century, we probably have more now than ever before," says James Gilbert, a professor of wildlife ecology at the University of Maine who is heading the 2001 survey.
When the results are compiled in December, the harbor seal count is expected to surpass 31,000, more than six times the count recorded in 1976.
The abundance of seals is the result of a plentiful food supply, a relatively clean environment and conservation laws that apparently work.
Before 1905, the state paid a $1 bounty on harbor seals to reduce their populations to help fish stocks, according to Steve Katona, a marine biologist and president of College of the Atlantic in Bar Harbor. Bounty hunters brought in seal noses to prove their kills.
The result was a seal population that was nearly exterminated along some parts of the coast -- with no noticeable effect on fish catches.
Maine lifted the bounty in 1905, but Massachusetts' wasn't lifted until 1968 and Canada in 1976.
Seal populations rebounded, but there were still only 5,000 or so off Maine in the early 1970s. Fishermen still sometimes killed them for interfering with nets and traps.
With passage of the Marine Mammal Protection Act of 1972, which made it illegal to kill seals, the numbers began growing in earnest. A 1981 survey identified about 10,000 seals, a survey five years later counted 12,000 and in 1997, the year of the last seal census, researchers counted about 31,000.
To count the seals, surveyors flew in two planes in the spring and shot 236 rolls of film -- a total of 8,496 pictures -- of hundreds of islands and ledges from New Hampshire to Canada. They used a slide projector to physically count the seals in each frame.
Researchers also attached radios to the backs of 30 seals in Rockland and in Chatham, Mass., to track their whereabouts, allowing scientists to estimate how many seals are in the water.
Studies along the Pacific coast estimate that there are 150 to 185 seals for every 100 that are counted, Gilbert said. If that is the case on the Atlantic coast as well, it could add up to more than 50,000 seals in Maine.