The U.S. National Oceanic and Atmospheric Administration (NOAA) is seeking comment on a proposed rule aimed at reducing ship strikes of whales.

There are six proposed rules to reduce whale strikes, including the one NOAA prefers: a vessel speed restriction of 10 knots or less in designated areas along the U.S. East Coast. The preferred alternative also includes a five-year sunset provision to allow for further consideration of ongoing scientific research, the administration said on its Website.

Collision with vessels is the leading human-caused source of mortality for the endangered North Atlantic right whale, the NOAA Website said.

Steve Collins, CLIA’s director of environmental and health programs, said speeds should be reduced when whales are present, but stopped short of endorsing the proposed rule.

“CLIA member lines have been working for several years with NOAA on vessel operations protective of the Right Whale. The low incidence of ship strikes is a testament to the diligence of ships, officers and crew, and we feel that alert navigational crews and a watchful eye, along with appropriate speed reduction when whales are present, are all tools to ensure protection,” Collins said. “Holland America Line was given an award by NOAA for a groundbreaking program on awareness avoidance and recognition.”

The comment period on the proposed rule ends Sept. 29.