Federal officials warn mariners that North Atlantic right whales have been spotted in the ocean south of the Vineyard, and a voluntary vessel restriction zone has been temporarily put in place to protect the endangered mammals.

The National Oceanographic and Atmospheric Administration said Thursday that 10 right whales, which are critically endangered, were spotted in the ocean south of the Vineyard and Nantucket on Feb. 24.

Voluntary speed restrictions are in place for waters around Vineyard and Nantucket until March 10. — Courtesy of NOAA

A dynamic management area has been established in these waters through March 10. Dynamic management areas are created after aggregations of whales are spotted; they are voluntary and mariners are requested to avoid these areas or to travel 10 knots or less inside the zones.

Right whales migrate seasonally from southern waters to the plankton-rich feeding ground off New England and Canada.

Mandatory speed restrictions of 10 knots or less are in effect seasonally in areas throughout the Atlantic coast, including Cape Cod Bay. Approaching a right whale closer than 500 yards is a violation of state and federal law.

Right whales are among the rarest of marine species, with an estimated population of 450. They are a federally listed endangered species.