Ship captains and boat operators hitting waters east of Boston, be advised: Officials from the National Oceanic and Atmospheric Administration have put in place voluntary speed restrictions following a recent sighting of three North Atlantic right whales not too far from the mouth of the city’s harbor.
The speed restriction zone, established by NOAA last week, extends 12 nautical miles east-to-northeast of Boston. Mariners are being asked not to exceed 10 knots — or roughly 11 miles per hour — inside the designated area.
The whales were first sighted in the region on March 25. The restrictions will remain in place through Sunday, officials said in a statement posted to the agency’s website. A map can be found online that pinpoints where vessel operators should keep an eye out for the whales to avoid contact.
Jennifer Goebel, a spokeswoman for NOAA, said exact coordinates of a right whale sighting are not divulged because officials don’t want people to take their boats out to try and find the marine animals. On top of that, she said, “whales move,” so their whereabouts could vary from minute to minute.
It’s a federal crime to come within 500 yards of the animals. Doing so carries a penalty of up to $100,000 and could lead to criminal charges.
“Every whale matters,” Goebel said in a telephone interview. “And vessel strikes are a problem, and one of the major causes of injury and mortality [for the whale].”
Tony LaCasse, a spokesman for the New England Aquarium, said whale-watch captains have been frequently seeing the large baleen whales as vessels make the trek toward Stellwagen Bank National Marine Sanctuary during daily tours.
LaCasse said they are relatively easy to identify as they skim-feed for copepods, a type of zooplankton.
“That entrance to the Boston Harbor is the very northern range of Cape Cod Bay, so you can have individual animals out there feeding,” LaCasse said.
Right whales are commonly spotted along parts of the state coastline this time of year, as mothers and their calves begin the long journey from the warm waters off Florida and Georgia up toward northern waters to feed.
Last year, as the whales arrived in the region, Amy Knowlton, a research scientist with the New England Aquarium, told the Globe that there is typically a “slow ramp-up in numbers,” followed by a quick departure in late April and early May.
Last month, federal fisheries officials asked operators of large ships to slow down or keep clear of an area south of Martha’s Vineyard, in order to protect 14 right whales that were seen there. It was the second time a voluntary speed restriction was placed on the area this year.
Currently, a seasonal speed restriction, which is mandatory, is in place off Race Point in Provincetown through April 30.