Humpback whale (Megaptera novaeangliae) numbers and distribution on their summer feeding grounds of the Eastern Aleutian Islands

Abstract

"In summer, Humpback whales (Megaptera novaeangliae) of the North Pacific stock feed in Alaska's nearshore waters. My research focused on the Bering Sea between Unimak and Samalga Pass with the objectives: 1) Estimate the number of humpback whales using the study area from 2001 through 2006; 2) Determine to what extent humpback whales exhibit site fidelity; 3) Describe the distribution of humpback whales and determine if depth, slope, and chlorophyll-a can predict the humpback whale presence. To investigate the degree to which whales return to the Eastern Aleutian summer feeding ground, 1,985 whale photographs were collected and an identity matrix was created; Humpback whales exhibited a 22 percent return rate with 181 whales out of 802 total whales seen in more than one year during the six year study. Program MARK (Mark and recapture parameter estimation) was used to estimate the number of humpback whales utilizing this area, resulting in an estimate of 500 to 1600 animals. Logistic regression and random forest classification determined that depth and longitude are significant predictors of humpback whale presence. These results support other studies in the Eastern Aleutians and North Pacific and further confirm the importance of oceanographic and biological features in concentrating prey and predicting humpback whale distribution"--Leaf iii