Steller Sea Lion (Eumetopias jubatus) Count Data from Glacier Bay National Park & Preserve, Alaska, 1996; 2001-2023

Steller sea lions (Eumetopias jubatus) are a highly social pinniped species and large aggregations of Steller sea lions occur in Glacier Bay National Park and Preserve, Alaska. Since the 1970s, the numbers of Steller sea lions have increased in the Glacier Bay region, with the most rapid growth occurring at South Marble Island, which was colonized by sea lions in 1985 (Mathews et al. 2011). Since 2001, sea lions have occupied the primary haulout site at South Marble Island throughout the year with additional new haulouts (Tarr Inlet, Point Carolus, Gloomy Knob) and a rookery at Graves Rocks (Womble et al. 2005; Womble et al. 2008; Mathews et al. 2011). Glacier Bay represents a dynamic “mixing zone” with sea lions from two genetically distinct population segments, eastern and western (west of 144˚W), occurring there (Jemison et al. 2013). The western population segment is listed as endangered under the Endangered Species Act, whereas the eastern segment was delisted in 2013 (National Marine Fisheries Service 2013). Data include counts of Steller sea lions from images collected during aerial photographic surveys and from opportunistic counts conducted by NPS staff and volunteers, primarily from vessels, in Glacier Bay National Park & Preserve in southeastern Alaska to assess the distribution, abundance, and trend of Steller sea lions from 1996; 2001-2023. From 2001-2006, aerial photographic surveys were conducted monthly and were part of University of Alaska Fairbanks-College of Fisheries & Ocean Sciences & NOAA study led by Jamie Womble, who was supported by Rasmuson Fisheries Research Fellowship. After 2006, surveys were primarily conducted in conjunction with harbor seal aerial surveys, with most surveys occurring during June-August and supported with support from the National Park Service. Please contact Jamie Womble if you have questions regarding these data, at jamienwombleak@gmail.com. Please see associated publications for more details. Streveler, G. 1989. Steller sea lion haul-out use history along Glacier Bay. Internal memorandum for Glacier Bay National Park & Preserve. October 1989. 1 pp. Womble, J.N. 2003. Seasonal distribution of Steller sea lions (Eumetopias jubatus) in relation to high-quality ephemeral prey species in southeastern Alaska. M.S. thesis. University of Alaska, Fairbanks, Alaska. https://scholarworks.alaska.edu/handle/11122/6657 Womble, J.N., Willson, M.F. Sigler, M.F., Kelly, B.P, and Van Blaricom, G.R. (2005) Distribution of Steller sea lions in relation to spring-spawning fish species in SE Alaska. Marine Ecology Progress Series 294: 271-282. https://www.int-res.com/articles/meps2005/294/m294p271.pdf Womble, J.N., Sigler, M.F. (2006) Seasonal availability of abundant, energy-rich prey influences the abundance and diet of a marine predator, the Steller sea lion. Marine Ecology Progress Series 325:281-293. https://www.int-res.com/articles/meps2006/325/m325p281.pdf Womble, J.N., Sigler, M.F., Willson, M.F. (2008) Linking seasonal distribution patterns with prey availability in a central- place forager, the Steller sea lion. Journal of Biogeography 36: 439-451. https://www.jstor.org/stable/pdf/20488371.pdf Womble, J.N., Gende, S.M. (2010) Contrasting trends for Steller sea lions and Steller sea lions in and near Glacier Bay National Park, Alaska. Alaska Park Science 9: 52-55. https://www.researchgate.net/profile/Jamie-Womble/publication/258407670_Contrasting_trends_of_harbor_seals_and_Steller_sea_lions_in_and_near_Glacier_Bay_National_Park_and_Preserve/links/0deec5372b4281c0b1000000/Contrasting-trends-of-harbor-seals-and-Steller-sea-lions-in-and-near-Glacier-Bay-National-Park-and-Preserve.pdf https://www.nps.gov/articles/aps-v9-i2-c12.htm Womble, J.N., Conlon, S. (2010) Observation of Steller sea lion predation on a Steller sea lion in the Glacier Bay region of southeastern Alaska. Aquatic Mammals 36: 129-137. https://www.researchgate.net/profile/Jamie-Womble/publication/228681494_Observation_of_Steller_Sea_Lion_Eumetopias_jubatus_Predation_on_a_Harbor_Seal_Phoca_vitulina_richardii_in_the_Glacier_Bay_Region_of_Southeastern_Alaska/links/00b49527bcf3ce17c0000000/Observation-of-Steller-Sea-Lion-Eumetopias-jubatus-Predation-on-a-Harbor-Seal-Phoca-vitulina-richardii-in-the-Glacier-Bay-Region-of-Southeastern-Alaska.pdf Allen, S.G., Brown, E., Faulkner, K., Gende, S.M., Womble, J. N. (2011) Conserving pinnipeds in Pacific Ocean parks in response to climate change. Park Science 28:48-52. https://www.researchgate.net/profile/Jamie-Womble/publication/258407609_Conserving_pinnipeds_in_Pacific_Ocean_parks_in_response_to_climate_chnage/links/0f3175372b3ec3667c000000/Conserving-pinnipeds-in-Pacific-Ocean-parks-in-response-to-climate-chnage.pdf Mathews, E.A., Womble, J.N., Pendleton, G.W, Jemison, L.A., Maniscalco, J.M., Streveler, G. (2011) Population expansion and colonization of Steller sea lions in the Glacier Bay region of southeastern Alaska: 1970s to 2009. Marine Mammal Science 27: 852-880. https://aleutmarinemammal.org/wp-content/uploads/2020/11/Pop-growth-colonization-Steller-sea-lions-Glacier-Bay-SE-Alaska-Matthews-2011.pdf Rehberg, M.J., Jemison, L.A., Womble, J.N., O’Corry-Crowe, G. (2018) Winter movements and long-term dispersal of Steller sea lions in the Glacier Bay region of southeastern Alaska. Endangered Species Research 37: 11-24. https://www.int-res.com/articles/esr2018/37/n037p011.pdf Womble, J.N. (2018). Influence of spring prey pulses on seasonal migrations of pinnipeds in and adjacent to Alaska’s National Parklands. Alaska Park Science 17:52-57. https://www.researchgate.net/publication/326044188_Influence_of_spring_prey_pulses_on_the_seasonal_distribution_and_migrations_of_pinnipeds_in_and_Adjacent_to_Alaska%27s_National_Parklands Whitlock, S.L., Womble, J.N., Peterson, J.T. (2020) Modelling pinniped abundance and distribution using counts at terrestrial sites and in-water sightings. Ecological Modelling 420, p.108965. https://core.ac.uk/download/pdf/345177336.pdf Additional publications related to Steller sea lion ecology, movements, and diving behavior in Glacier Bay can also be found on Data Store or: https://www.researchgate.net/profile/Jamie-Womble?ev=prf_overview https://scholar.google.com/citations?user=4zSbT-gAAAAJ&hl=en

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