Changes in humpback whale occurence in the Washington-southern British Columbia feeding area
Steiger, GH, J Calambokidis, M Malleson, AB Douglas, E Falcone, SJ Jeffries, B Gisborne, JK Ford. 2015. Changes in humpback whale occurence in the Washington-southern British Columbia feeding area. Abstract (Proceedings) 21st Biennial Conference on the Biology of Marine Mammals, San Francisco, California, December 14-18, 2015.
Based on past genetic and photo-identification data, humpback whales in the North Pacific show site fidelity to distinct feeding areas to which they return annually including an area that encompasses the waters off Washington and southern British Columbia. This represents one of the smaller North Pacific feeding areas both geographically and numerically. Combined with its transboundary status and busy shipping-lane traffic through this area from both US and Canada ports, this is an important but complicated area for management. We examine changes in humpback whale occurrence based on line-transect surveys conducted off northern Washington from 1995 to 2008 as well as broader surveys in 2011-2013 and mark-recapture calculations based on photographic identification in this region. Mark-recapture abundance estimates show an increase from 100-200 animals in the late 1990s to about 700 in most recent years. Similarly the occurrence of humpback whales in the inside waters of Washington/BC (Salish Sea) have increased and become a more regular focus of whale-watch operations. Once common in the Salish Sea, even during winter months, humpback whales were largely extirpated by local whaling operations in the early 1900s. With the newly proposed recognition of Distinct Population Segments (DPS) under the US Endangered Species Act (ESA) based on breeding regions, some with different status designations, better information on the breeding destinations of whales feeding off Washington and southern British Columbia is important. Whales from this area have been documented at a range of breeding regions, including a small number seen in Central America, one of the proposed DPSs that would continue to be listed under the ESA. We document the increase in humpback whales and their return to inside waters where they were once common.