Population characteristics of humpback whales in Glacier Bay and adjacent waters: 1998

Gabriele, Christine; Doherty, Janet

We photographically identified 92 individual humpback whales (Megaptera novaeangliae), including 8 calves, in Glacier Bay and Icy Strait between June 1 and August 31, 1998. This is the highest number of whales documented in the study area since the monitoring program began in 1985, contributing to a statistically significant increasing trend for the time period of 1985-1998. Thirty-two whales were resident' in Glacier Bay and 16 were resident' in Icy Strait for more than 20 days. We observed an unusually high number of incidences of bubblenet feeding (n=10) from single whales or pairs of whales in upper Glacier Bay. Bubblenet feeding was associated with prey patches extending 5-20 meters from the water's surface. Whale #1299, the 1997 calf of #161, returned as a yearling, bringing the 1974-1998 total number of returning offspring to 26. Whale #1031, born in 1988 to female #219, was identified with a calf for the first time, although we cannot determine whether the 1998 calf is her first, due to the lack of sighting data during 1992 and 1994. Several interactions between float planes and whales were observed in Bartlett Cove, as well as a reported whale entanglement in Icy Strait, which we could not confirm.