PORTLAND – Researchers are still eager to hear from people who have seen oil-covered loons or carcasses even as they wrap up their work after a 98,000-gallon oil spill last spring.

Kate Taylor, senior biologist at the Loon Preservation Committee in Moultonborough, N.H., said it’s unlikely that a loon covered in oil would have survived this long. But it’s possible.

The spill of No. 6 fuel oil – a heavy oil used by ocean liners, tankers and power plants – occurred in Buzzards Bay off Massachusetts during the loon migration last April.

So far 200 dead loons have been recovered, and researchers have been working through the summer to find oiled loons in New Hampshire, Maine, Vermont, Massachusetts and Canada’s Maritime provinces.

Scientists are using genetic information gathered from the birds, along with weight, bill length and other measurements, in a precedent-setting project that will help them pinpoint which state’s loons were most affected by the spill.

The results will help determine how much the responsible party will have to pay in reparations, and who will get the check.

It is never too late to report a dead loon, “no matter how gross they are,” Taylor said. “We get them in all different conditions, but you can usually gain some bit of information from every carcass.”

Taylor’s group has been collaborating with the U.S. Fish and Wildlife Service, the BioDiversity Research Institute in Falmouth, and a wildlife geneticist at Buffalo State College in Buffalo, N.Y., to document the spill’s impact on loons.

The project is building on work that was done after the 1996 North Cape oil spill in Rhode Island, which killed more than 400 wintering loons.

In that case, biologists assigned an economic value to the dead loons by figuring out that the oil spill resulted in the loss of about 4,000 “loon years,” said David Evers, executive director of the BioDiversity Research Institute.

Then they calculated that in order to compensate for that loss, 24 nesting pairs of loons would have to be protected for at least 100 years.

Lawyers challenged the biologists through every step of the negotiating process, Evers said, but all those years of banding loons in Maine and gathering information about them paid off.

“We have such great information on loons for New England that we were able to answer every question,” he recalled. “They were kind of stuck in a corner, and finally had to say, ‘OK, you’re right and here’s the money.”‘

When $3.2 million in compensation came through, the money was earmarked for the purchase of shoreline breeding habitat for loons in Maine, coupled with a five-year monitoring program.

But the choice to protect breeding habitat in Maine instead of choosing some other New England site was relatively random.

This time, researchers want to identify the home of the loons to determine which state was hit hardest in terms of loss of loons.

“Before, we couldn’t really define which state’s population took a hit,” Taylor said. “Now we’re getting closer.”