For years, fishermen in Maine and down the East Coast have complained that they have had to make major gear changes to spare right whales, yet ships, the major killer of the endangered cetaceans, have been let off the hook. That would change under a new strategy proposed last week by the National Marine Fisheries Service.

There are only 300 right whales believed to live in the northern Atlantic Ocean now. The death of just one whale is a violation of the federal Endangered Species Act. The cause of death is often hard to pinpoint because whales have often shed the fishing lines that entangled them or are found far from where they collided with a ship.

Half of all right whale deaths are attributable to human activities, according to data from the New England Aquarium. Forty percent of the deaths are due to collisions with ships and 10 percent happen after whales get tangled in fishing gear. NMFS has different numbers. About two-thirds of the known deaths are likely owing to natural causes, according to the agency. Of the one-third caused by human activities, the most significant contributing factors are ship strikes and entanglement in fishing gear, with ship-strike related deaths slightly higher than entanglements among known causes of death, NMFS says.

Although both entities agree that ships are the larger problem, regulations have focused on fishing gear changes and putting areas where whales are known to live or pass through off limits to fishing. Lobstermen have starting using “negative buoyancy” line that hovers in the water rather than dragging on the bottom and have stopped using knots in their lines since they can get stuck in a whale’s mouth.

It is believed that these gear changes have made a difference although right whale entanglement and mortality numbers are so low – and influenced by the number of people looking for entangled or dead animals – that changes from year to year are hard to interpret.

Fishermen have done their part, so given the precarious position of right whales it is time for more rules for ships. Because the animals are slow moving and spend much time at the surface, they are vulnerable to collisions with ships. Solutions recommended by NMFS include re-routing ships longer than 65 feet around the highest-risk areas and reductions in speed in those areas. The agency is now collecting public comment on these strategies before setting to work on drafting proposed rules.

Although details, such as the in-creased cost to shippers – and ultimately consumers – of re-routing ships or slowing them down, need to be worked out, the agency is right to ask the shipping industry to share in the responsibility of not harming whales.