California sea lions, harbor seals, and long-beaked common dolphins forage on anchovies in south Puget Sound
Presentation Abstract
California sea lion (Zalophus californianus) males typically occupy inland and coastal waters of Washington State for up to 10 months of each year except during pupping and breeding season (May –July) when they return to rookery islands in Southern California. Adult females and juvenile animals are rarely found in Washington waters. It has been recognized that California sea lion males enter inland waters of Washington to feed in August and their numbers build to seasonal high numbers by December and then become less abundant from January through March when numbers again peak in April before they depart in May for the spring migration to the breeding rookeries in Southern California. Most of these seasonal movements appear to be in response to changes in prey abundance with seasonal increases in prey species including salmon, market squid, herring and eulachon smelt known drivers for these movements. Since 2015, the anchovy biomass in southern Puget Sound has been off the charts and has attracted a number of pinnipeds and cetaceans to feed on this abundant food resource. This includes 300-400 California sea lions that has been foraging on this large anchovy biomass from January through March. In 2019, this large group of California sea lions was feeding in the north end of Case Inlet, along with harbor seals, long beaked common dolphins and harbor porpoise, on this large anchovy biomass. Using synchronous diving, with multiple species working together, these California sea lions and with other species had this anchovy biomass “corralled” in the north end of Case Inlet through the spring. This large congregation of sea lions (and other marine mammals) dispersed from Case Inlet at the end of March after transient killer whales moved south of the Tacoma Narrows and were active in Case Inlet for several days!
Session Title
Session 1.2 A: Trophic energy flow in the Salish Sea: Part IV (Marine Mammals)
Conference Track
Trophic Interactions - Zooplankton, Phytoplankton, Salmon, Forage Fish & Invasive Species
Conference Name
Salish Sea Ecosystem Conference (2020 : Online)
Document Type
Event
SSEC Identifier
2020_abstractID_4893
Start Date
21-4-2020 12:30 PM
End Date
21-4-2020 2:00 PM
Genre/Form
conference proceedings; presentations (communicative events)
Subjects – Topical (LCSH)
California sea lion--Food--Washington (State)--Puget Sound; Harbor seal--Washington (State)--Puget Sound; Dolphins--Food--Washington (State)--Puget Sound; Anchovies--Effect of predation on--Washington (State)--Puget Sound
Geographic Coverage
Salish Sea (B.C. and Wash.); Puget Sound (Wash.)
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
Format
application/pdf
California sea lions, harbor seals, and long-beaked common dolphins forage on anchovies in south Puget Sound
California sea lion (Zalophus californianus) males typically occupy inland and coastal waters of Washington State for up to 10 months of each year except during pupping and breeding season (May –July) when they return to rookery islands in Southern California. Adult females and juvenile animals are rarely found in Washington waters. It has been recognized that California sea lion males enter inland waters of Washington to feed in August and their numbers build to seasonal high numbers by December and then become less abundant from January through March when numbers again peak in April before they depart in May for the spring migration to the breeding rookeries in Southern California. Most of these seasonal movements appear to be in response to changes in prey abundance with seasonal increases in prey species including salmon, market squid, herring and eulachon smelt known drivers for these movements. Since 2015, the anchovy biomass in southern Puget Sound has been off the charts and has attracted a number of pinnipeds and cetaceans to feed on this abundant food resource. This includes 300-400 California sea lions that has been foraging on this large anchovy biomass from January through March. In 2019, this large group of California sea lions was feeding in the north end of Case Inlet, along with harbor seals, long beaked common dolphins and harbor porpoise, on this large anchovy biomass. Using synchronous diving, with multiple species working together, these California sea lions and with other species had this anchovy biomass “corralled” in the north end of Case Inlet through the spring. This large congregation of sea lions (and other marine mammals) dispersed from Case Inlet at the end of March after transient killer whales moved south of the Tacoma Narrows and were active in Case Inlet for several days!
