Sperm whales associated with Gulf Stream features off the north‐eastern USA shelf

Marine mammal surveys were conducted during sum Mer 1990 and 1991 in shelf‐edge and off‐shelf waters between Cape Hatteras and Georges Bank. Sperm whales were the most frequently sighted large whale in both years, constituting 27.9% and 12.7% of total sightings in 1990 and 1991, respectively. Sighting rates of sperm whales that were within a 9.3 km buffer (5 n.m.) of the Gulf Stream north wall were not significantly different ( x 2 = 2.86, P > 0.05) from those within the Gulf Stream during 1990. In 1991, however, significantly more ( x 2 = 51.0, P < 0.05) sightings were associated with shelf‐edge areas where warm core rings were located.