Distribution and abundance of cetaceans in the vicinity of human activities along the continental shelf of the Northwestern Atlantic

The distribution and abundance of cetaceans were investigated in the vicinity of oil rigs, surface oil and boat traffic along the continental shelf of the northwestern Atlantic. Data concerning the total number of cetacean sightings and individuals were obtained from dedicated aerial surveys conducted between January, 1979 and January, 1982. Sightings per unit effort and individuals per unit effort for areas surrounding active oil rigs were not significantly different from those found in the same areas when no oil rigs were present. Surface oil was sighted ninety-four times. Cetacean sightings were made in the vicinity of oil on eleven different occasions and in oil twice. None of these animals was noted as displaying unusual behavior and no feeding was observed. The presence of boat traffic was found to decrease the probability of sighting squid-eating cetaceans but had no apparent effect on the probability of sighting fish-eating cetaceans.