The giant whale was swimming in the Northeast Canyons and Seamounts Marine National Monument, a marine sanctuary off the coast of Nantucket. The second sighting was of two other blue whales, and took place only 24 hours later. One of two blue whales sighted over southern New England waters on Feb. 28, 2026 (right). Researchers don’t know very much about the Western North Atlantic Blue whale population, and theorize that they might amount to just 400–600 whales. Thankfully, blue whales’ global numbers are going up.