title: Timing of ice retreat alters seabird abundances and distributions in the southeast Bering Sea.
abstract: Timing of spring sea-ice retreat shapes the southeast Bering Sea food web. We compared summer seabird densities and average bathymetry depth distributions between years with early (typically warm) and late (typically cold) ice retreat. Averaged over all seabird species, densities in early-ice-retreat-years were 10.1% (95% CI: 1.1-47.9%) of that in late-ice-retreat-years. In early-ice-retreat-years, surface-foraging species had increased numbers over the middle shelf (50-150 m) and reduced numbers over the shelf slope (200-500 m). Pursuit-diving seabirds showed a less clear trend. Euphausiids and the copepod Calanus marshallae/glacialis were 2.4 and 18.1 times less abundant in early-ice-retreat-years, respectively, whereas age-0 walleye pollock Gadus chalcogrammus near-surface densities were 51× higher in early-ice-retreat-years. Our results suggest a mechanistic understanding of how present and future changes in sea-ice-retreat timing may affect top predators like seabirds in the southeastern Bering Sea.
authors.affiliation: Tern Again Consulting, 811 Ocean Drive Loop, Homer, AK 99603, USA ccc4f4b0@opayq.com.
authors.forename: Martin
authors.identifier: 0000-0003-0346-1024
authors.initials: M
authors.lastname: Renner
authors.affiliation: NOAA-Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115, USA.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Salo
authors.affiliation: NOAA-Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA.
authors.forename: Lisa B
authors.initials: LB
authors.lastname: Eisner
authors.affiliation: NOAA-Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA.
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Ressler
authors.affiliation: NOAA-Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115, USA.
authors.forename: Carol
authors.initials: C
authors.lastname: Ladd
authors.affiliation: US Fish and Wildlife Service, Migratory Bird Management, 1011 E. Tudor Road, Anchorage, AK 99503, USA.
authors.forename: Kathy J
authors.initials: KJ
authors.lastname: Kuletz
authors.affiliation: University of California Santa Cruz, 110 Shaffer Road, Santa Cruz, CA 95060, USA.
authors.forename: Jarrod A
authors.initials: JA
authors.lastname: Santora
authors.affiliation: US Geological Survey, 4210 University Drive, Anchorage, Alaska 99508, USA.
authors.forename: John F
authors.initials: JF
authors.lastname: Piatt
authors.affiliation: US Geological Survey, 4210 University Drive, Anchorage, Alaska 99508, USA.
authors.forename: Gary S
authors.initials: GS
authors.lastname: Drew
authors.affiliation: University of Washington, PO Box 355020, Seattle, WA 98195, USA.
authors.forename: George L
authors.initials: GL
authors.lastname: Hunt
mesh_terms: D000818:Animals; D001110:Arctic Regions; D001717:Birds / Q000502:physiology*; D033342:Copepoda; D017753:Ecosystem; D033201:Euphausiacea; D020387:Food Chain; D048388:Gadiformes; D046448:Ice Cover; D010140:Pacific Ocean; D012621:Seasons; D015048:Zooplankton
keywords: climate change; fisheries; sea ice; seabirds at sea; walleye pollock; zooplankton