Overview of baleen whale feeding behavior and prey in the Salish Sea

• Main Author: Calambokidis, John
• Format: Text
• Language: English
• Published: Western CEDAR 2020
• Subjects: Fresh Water Studies; Life Sciences; Marine Biology; Natural Resources and Conservation; Terrestrial and Aquatic Ecology; San Juan; Pacific; baleen whale; baleen whales
• Online Access: https://cedar.wwu.edu/ssec/2020ssec/allsessions/65

Several species of baleen whales feed in the waters of N Washington and S British Columbia including within the Salish Sea and recent research has revealed more about their occurrence, numbers, and feeding. Most numerous are humpback whales which have seen a steady overall increase in numbers especially in their occurrence in the Salish Sea as they return to waters they used prior to whaling. Humpback whales along the US West Coast regularly feed on both smaller schooling fish as well as krill with their predominant prey varying by year depending on availability. The first deployments of archival tags within the Salish Sea in July and September 2018 revealed humpback whales feeding primarily during the day on krill near the bottom at depths of 120-150 m. While most of the eastern North Pacific gray whale population migrates along the west coast without entering the inland waters of Washington and Southern British Columbia, two groups feed in the Salish Sea. Members of the Pacific Coast Feeding Aggregation (PCFG), which number a couple of hundred animals, feed in Pacific NW waters including nearshore waters of the Strait of Juan de Fuca from spring to fall on a variety of prey, especially swarms of Mysid shrimp. A small portion of the overall gray whale population feed annually in spring during their northbound migration in several areas including a dozen individuals that feed almost exclusively on ghost shrimp in the waters around Whidbey Island. Minke whales feed seasonally in the Salish Sea especially around banks in the eastern Strait of Juan de Fuca and around the San Juan Islands targeting primarily small schooling fish. While these three baleen whale species are most common, fin, blue, and right whales have also been documented occasionally in or just outside the Salish Sea, primarily in outside waters.