If the whales can see the fishing gear more clearly, then they are better able to avoid it, said Scott Kraus, a leading researcher on northern right whales.
"We know they can see the ropes. We thought by making them more visible they might be like traffic cones" by steering whales away from danger, Kraus said at the Maine Fishermen's Forum, an annual fishing industry event that draws together fishermen, regulators, researchers and other industry officials.
North Atlantic right whales, whose large eyes are adapted to the low light of the ocean, may be more sensitive to certain colors, the New England Aquarium scientist said.
Kraus and other researchers set out three years ago to determine whether the whales respond to some colors more than others. Intercepting feeding whales in Cape Cod Bay, off the shore of Massachusetts, they placed in the water lengths of colored PVC pipe, representing pieces of rope that attach traps to buoys.
When the whales approached, the scientists measured the distance from the whales' eyes at the moment when they reacted to the suspended "rope."
Not all colors evoked the same reaction.
On average, the scientists discovered that right whales were most likely to respond to orange or red, and they were less likely to react to green and black, Kraus said.
Although the whales see their ocean world in black-and-white, it makes sense that they can differentiate orange from other colors since the clouds of zooplankton upon which they feed are orange in color, said Michael Moore, director of the marine mammal center at the Woods Hole Oceanographic Institution in Massachusetts.
The research was long overdue, Moore said, because fishing gear entanglements are common.
More than 80 percent of right whales show evidence of having been entangled in some type of fishing gear and the whales acquire a new entanglement scar once every three years on average, he said.
"The problem of entanglement of large whales, right whales, in fixed fishing gear is huge. It doesn't seem that way to an individual fisherman. From the whale's perspective it's a daily occurrence," he said.
It's a big problem for North Atlantic right whales because there are so few of them. Experts estimate there are only about 450 of the whales, which grow up to 55 feet long and weigh up to 70 tons.
More research needs to be done, said Kraus, who intends to publish his preliminary findings sometime in the next six months.
But based on those early results, he is working with Brooks Trap Mill and Hyliner Rope to manufacture experimental red ropes that are being tested by Maine lobstermen for durability and handling.
Some lobstermen are skeptical the ropes will make a difference.
"No lobsterman is going to use red rope," said Ryan Post, a fourth generation lobsterman who fishes off Metinic Island. "We've tried them in the past, and they faded pink."
Associated Press writer David Sharp in Portland, Maine, contributed to this report.