PORTLAND – Scientists are studying endangered right whales this summer to learn more about their behavior and assess the risks posed by lobster gear.

Three initiatives are under way in New England aimed at developing gear that won’t harm the whales without putting too much of a burden on Maine’s nearly 6,000 commercial lobstermen.

The efforts come as the federal government considers a new rule that would ban floating lobster lines. Supporters of the rule say keeping rope between traps closer to the bottom would help to prevent right whales from becoming entangled.

Some fishermen are in denial about the new rule, but most are anxious about how it will affect them financially, said Jeff White, a 37-year-old lobsterman from York.

“It’s hanging over our heads,” he said.

Conservationists have lobbied for years for the right whale. Only 300 or so remain, and most have scars from entanglements with fishing gear.

But a lot is still unknown about the animals, which spend the winter in warm waters to the south and migrate to the Gulf of Maine each spring before returning south in the fall.

There’s a lot that scientists don’t know about how the whales behave when they’re in Maine waters because they are so hard to find, said Erin Summers, a scientist with the Maine Department of Marine Resources.

Before federal policymakers issue new rules on lobster gear, she said, they should know whether whales feed over Maine’s rocky bottom and how deep they dive if they do feed. Right now, nobody knows, she said.

She hopes a group of scientists on board the R/V Stellwagen will find some answers this summer when they use suction cups to attach tags to right whales. The vessel is standing ready to leave Salem, Mass., as soon as a group of right whales spotted near Georges Bank off southern New England moves into the Gulf of Maine.

The team then will drop a set of buoys into the water that will emit electronic signals to the tags, allowing researchers to track the whales’ movements over an 18-hour period and observe where they swim and how far above the ocean bottom they are.

“We are trying to understand what their behavior is in the water column so regulations made for the lobster industry aren’t based on guessing,” said Alex Loer, owner and captain of the vessel.

The project, which will continue until July 10, will take place between Mount Desert Rock, a treeless island about 25 miles off Mount Desert Island, and Jeffreys Ledge off the New Hampshire and southern Maine coasts.

Meanwhile, researchers at the Maine Department of Marine Resources are working with fishermen to test different types of “low-profile” lines, which float just a few feet off the ocean floor to reduce chafing on the rocky bottom. Tiny electronic recording devices attached to the lines provide information about how far off the bottom the lines float during different stages of the tide cycle.

In yet another project, a consortium called the Conservation for Wildlife Bycatch Reduction this summer is testing abrasion-resistant ground lines. The group includes representatives from the University of New Hampshire, Duke University, the Maine Lobstermen’s Association and the New England Aquarium.

In recent years, the group has tested several “crazy” ideas, such as glow-in-the-dark lines and lines encased in rubber, said Patricia McCarron, executive director of the Maine Lobstermen’s Association.

“If they make it, we are finding fishermen to give it a field test,” she said. “We are taking this very seriously. We aren’t going to say no until we try it out.”