Numbers and seasonal occurrence of Humpback Whales, Megaptera novaeangliae, off Brier Island, Nova Scotia

Humpback Whales, Megaptera novaeangliae, were studied using individual photo-identification in the waters off Brier Island, Nova Scotia, during the years 1984 to 1996. Estimates of the number of whales visiting the area were obtained for each year using mark-recapture methods. The population size has a variance weighted mean of 80 ± 5 (95% CI) for repeated Petersen estimates. There was consistency between estimates from 1984 to 1993 but a decline was seen in 1994 and 1995. These estimates represent approximately 38% of the estimated total population of Humpback Whales of the Gulf of Maine feeding aggregation and approximately 1.8% of the total Western North Atlantic Ocean population. Off Brier Island, a pattern of seasonal variation in sighting rates for half-month periods was observed for the years 1985 to 1989. The results indicate that Humpback Whales arrive slowly in the area during June, reach a population peak around August, the period of greatest plankton abundance, and depart from the area between then and October.