But measures such as slowing down ships or retrofitting them with new, more efficient propellers are costly and may not even work, she said.
Study off Mass. coast finds noise harming whales →
"We're kind of a slow industry," Metcalf said. "But the bottom line is if we could do something now that can be used as guidelines for new construction, 15 years from now, half the world's fleet would have already been built that way."