In this March 28, 2018, file photo, a North Atlantic right whale feeds on the surface of Cape Cod bay off the coast of Plymouth, Massachusetts. Credit: Michael Dwyer / AP

NANTUCKET, Massachusetts — Federal authorities are implementing a speed restriction zone southeast of Nantucket due to the presence of an endangered species of whale in the area.

The National Oceanic and Atmospheric Administration said the voluntary vessel speed restriction zone was triggered by an observation of North Atlantic right whales on Dec. 14. The whales number 366 in the world and they are vulnerable to ship strikes and entanglement in fishing gear.

NOAA has asked mariners to avoid the area altogether or travel through it at 10 knots or less. The whales were spotted by an aerial survey team from the New England Aquarium.

The slow zone is in effect through Dec. 29, NOAA said.

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