In May of 2001, the California Department of Fish and Game (CDFG) conducted an aerial photographic survey of the California coast and the offshore Channel Islands to obtain a minimum estimate of the population of harbor seals (Phoca vitulina richardsi) living in California. The developed photographs were examined to count the number of harbor seals present and determine the location of each haul-out site by comparison to photos taken in previous surveys. This survey was successful in obtaining nearly complete coverage of all known haul-out areas. The 1995 survey was the last complete coverage. The total county for 2001 is 12,312 harbor seals. This result is the lowest ever recorded by CDFG for a combined count of the mainland and all offshore islands. The California Department of Fish and Game (CDFG) conducted two surveys in 2002 in an attempt to provide better coverage and to lessen the chances of weather related problems. A total of 16 days were scheduled for aerial surveys from May 19 to July 19, 2002. Total count for Survey 1 was 10,541 harbor seals, while that for Survey 2 was 8,374 harbor seals. Camera problems that produced un-readable film and poor weather conditions prevented a complete assessment by either survey. The lack of complete coverage by either Survey 1 or 2 limited the total number of harbor seals counted. This is especially true in areas where past surveys revealed high concentrations of seals such as the northern Channel Islands and Point Reyes - Sonoma County coast. The California Department of Fish and Game (CDFG) conducted two aerial surveys in 2003 in an attempt to provide better coverage and to lessen the chances of weather related problems. A total of 20 days were scheduled for aerial surveys from May 25 to July 20, 2003. Complete coverage was achieved in both surveys. This was the first time CDFG conducted these surveys using a digital imaging camera. Total count for Survey 1 was 17,415, while that for Survey 2 was 17,778 harbor seals.

In May of 2001, the California Department of Fish and Game (CDFG) conducted an aerial photographic survey of the California coast and the offshore Channel Islands to obtain a minimum estimate of the population of harbor seals (Phoca vitulina richardsi) living in California. The developed photographs were examined to count the number of harbor seals present and determine the location of each haul-out site by comparison to photos taken in previous surveys. This survey was successful in obtaining nearly complete coverage of all known haul-out areas. The 1995 survey was the last complete coverage. The total county for 2001 is 12,312 harbor seals. This result is the lowest ever recorded by CDFG for a combined count of the mainland and all offshore islands. The California Department of Fish and Game (CDFG) conducted two surveys in 2002 in an attempt to provide better coverage and to lessen the chances of weather related problems. A total of 16 days were scheduled for aerial surveys from May 19 to July 19, 2002. Total count for Survey 1 was 10,541 harbor seals, while that for Survey 2 was 8,374 harbor seals. Camera problems that produced un-readable film and poor weather conditions prevented a complete assessment by either survey. The lack of complete coverage by either Survey 1 or 2 limited the total number of harbor seals counted. This is especially true in areas where past surveys revealed high concentrations of seals such as the northern Channel Islands and Point Reyes - Sonoma County coast. The California Department of Fish and Game (CDFG) conducted two aerial surveys in 2003 in an attempt to provide better coverage and to lessen the chances of weather related problems. A total of 20 days were scheduled for aerial surveys from May 25 to July 20, 2003. Complete coverage was achieved in both surveys. This was the first time CDFG conducted these surveys using a digital imaging camera. Total count for Survey 1 was 17,415, while that for Survey 2 was 17,778 harbor seals.

In May of 2001, the California Department of Fish and Game (CDFG) conducted an aerial photographic survey of the California coast and the offshore Channel Islands to obtain a minimum estimate of the population of harbor seals (Phoca vitulina richardsi) living in California. The developed photographs were examined to count the number of harbor seals present and determine the location of each haul-out site by comparison to photos taken in previous surveys. This survey was successful in obtaining nearly complete coverage of all known haul-out areas. The 1995 survey was the last complete coverage. The total county for 2001 is 12,312 harbor seals. This result is the lowest ever recorded by CDFG for a combined count of the mainland and all offshore islands. The California Department of Fish and Game (CDFG) conducted two surveys in 2002 in an attempt to provide better coverage and to lessen the chances of weather related problems. A total of 16 days were scheduled for aerial surveys from May 19 to July 19, 2002. Total count for Survey 1 was 10,541 harbor seals, while that for Survey 2 was 8,374 harbor seals. Camera problems that produced un-readable film and poor weather conditions prevented a complete assessment by either survey. The lack of complete coverage by either Survey 1 or 2 limited the total number of harbor seals counted. This is especially true in areas where past surveys revealed high concentrations of seals such as the northern Channel Islands and Point Reyes - Sonoma County coast. The California Department of Fish and Game (CDFG) conducted two aerial surveys in 2003 in an attempt to provide better coverage and to lessen the chances of weather related problems. A total of 20 days were scheduled for aerial surveys from May 25 to July 20, 2003. Complete coverage was achieved in both surveys. This was the first time CDFG conducted these surveys using a digital imaging camera. Total count for Survey 1 was 17,415, while that for Survey 2 was 17,778 harbor seals.

Harbour seals (Phoca vitulina) are found along temperate and Arctic marine coastlines of the Northern Hemisphere. They are found in coastal waters of the northern Atlantic and Pacific Oceans, as well as those of the Baltic and North Seas. In Canada, they may be found off the coastal waters of British Columbia, Nunavut, Manitoba, Ontario, Quebec, New Brunswick, Prince Edward Island, Nova Scotia, and Newfoundland and Labrador. Population trends and abundance of harbour seals in British Columbia are assessed based on aerial surveys conducted during 1966-2019. Based on counts conducted in Index Areas distributed throughout the province, the trend observed in the Strait of Georgia appears to be generally indicative of harbour seal populations throughout British Columbia. Total abundance of harbour seals on the B.C. coast in 2008 was estimated to be on the order of about 105,000 (95% confidence interval of 90,900 to 118,900) seals. Total abundance was re-estimated in 2022 (estimate and CI pending completion of CSAS process). Historic reconstructions indicate the population was depleted by a period of commercial harvesting during 1879-1914, and subsequently maintained below natural levels by predator control programs until the early 1960s. Already depleted, the population could not sustain a second period of intense commercial harvesting during 1962-1968 and was further depleted, but now appears to have fully recovered.

Population monitoring studies of harbor seals in Glacier Bay National Park, Alaska, have spanned five decades from the 1970’s to the present (Streveler 1979; Calambokidis et al. 1987; Mathews & Pendleton 2006; Womble al. 2010; Womble et al. 2020; Womble et al. 2021), representing one of just a few sites in in Alaska where such long-term monitoring effort exists. Monitoring methods for harbor seals at terrestrial sites have remained consistent since 1992 allowing for quantifying distribution, abundance, and trend of harbor seals in Glacier Bay National Park. This file includes data includes count data of harbor seals from digital photographs collected during aerial photographic surveys conducted in Glacier Bay National Park & Preserve in southeastern Alaska to assess the distribution, abundance, and trend of harbor seals at terrestrial and glacier ice sites (McBride Inlet and Tarr Inlet) from 2004 to 2023. Aerial photographic surveys were conducted from May-September, with most surveys occurring during May-June (pupping period) and July-September (molting period). Replicate aerial surveys (2-4 surveys during pupping and molting period) were conducted to increase precision in the trend estimates of harbor seals. If it was not possible to complete at least 4 replicate surveys on different days during one tidal cycle, then surveys were attempted during the second low tidal cycle of the month, weather permitting. From 2004-2025 this project was led by Jamie N. Womble (National Park Service), please contact Jamie if you have questions regarding these data, at jamienwombleak@gmail.com. Please see associated publications for more details. Womble, J.N., Williams, P.J., McNabb, R., Prakash, A., Gens, R., Sedinger, B. and Acevedo, C. (2021). Harbor Seals as Sentinels of Ice Dynamics in Tidewater Glacier Fjords. Frontiers in Marine Science, 8, pp.1-16. https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.634541/full Blanchet, M.A., Vincent, C., Womble, J., Steingass, S. and Desportes, G., (2021). Harbour Seals: Population Structure, Status, and Threats in a Rapidly Changing Environment. In Oceans (Vol. 2, No. 1, pp. 41-63).https://www.mdpi.com/2673-1924/2/1/3 Womble, J.N., Ver Hoef, J.M, Mathews, E.A., Gende, S.M. (2020). Calibrating and adjusting counts of harbor seals in a tidewater glacier fjord to estimate abundance and trends 1992-2017. Ecosphere 11(4), p.e03111. https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.3111 Womble, J.N. 2012. Foraging ecology, diving behavior, and migration patterns of harbor seals (Phoca vitulina richardii) from a glacial fjord in Alaska in relation to prey availability and oceanographic features. Ph.D. Dissertation. Oregon State University, Corvallis, Oregon. Blundell, G.M., Womble, J.N., Pendleton, G.W., Karpovich, S.A., Gende, S.M., Herreman, J.K. (2011) Use of glacial ice and terrestrial habitats by harbor seals in Glacier Bay, Alaska: costs and benefits. Marine Ecology Progress Series 429:277- 290. https://www.int-res.com/articles/meps_oa/m429p277.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 Womble, J.N., Pendleton, G.W., Mathews, E.A., Blundell, G.M., Bool, N.M., Gende, S.M. (2010) Harbor seal decline continues in the rapidly changing landscape of Glacier Bay National Park, Alaska, 1992-2008. Marine Mammal Science 26:686-697https://onlinelibrary.wiley.com/doi/10.1111/j.1748-7692.2009.00360.x?msockid=14da1e5b94b961b802740be595036098 Womble, J.N., Pendleton, G.W., Mathews, E.A., Gende S.M. (2015). Status and trend of harbor seals at terrestrial sites in Glacier Bay National Park from

Population monitoring studies of harbor seals in Glacier Bay National Park, Alaska, have spanned five decades from the 1970’s to the present (Streveler 1979; Calambokidis et al. 1987; Mathews & Pendleton 2006; Womble al. 2010; Womble et al. 2020; Womble et al. 2021), representing one of just a few sites in in Alaska where such long-term monitoring effort exists. Monitoring methods for harbor seals at terrestrial sites have remained consistent since 1992 allowing for quantifying distribution, abundance, and trend of harbor seals in Glacier Bay National Park. This file includes data includes count data of harbor seals from digital photographs collected during aerial photographic surveys conducted in Glacier Bay National Park & Preserve in southeastern Alaska to assess the distribution, abundance, and trend of harbor seals at terrestrial and glacier ice sites (McBride Inlet and Tarr Inlet) from 2004 to 2023. Aerial photographic surveys were conducted from May-September, with most surveys occurring during May-June (pupping period) and July-September (molting period). Replicate aerial surveys (2-4 surveys during pupping and molting period) were conducted to increase precision in the trend estimates of harbor seals. If it was not possible to complete at least 4 replicate surveys on different days during one tidal cycle, then surveys were attempted during the second low tidal cycle of the month, weather permitting. From 2004-2025 this project was led by Jamie N. Womble (National Park Service), please contact Jamie if you have questions regarding these data, at jamienwombleak@gmail.com. Please see associated publications for more details. Womble, J.N., Williams, P.J., McNabb, R., Prakash, A., Gens, R., Sedinger, B. and Acevedo, C. (2021). Harbor Seals as Sentinels of Ice Dynamics in Tidewater Glacier Fjords. Frontiers in Marine Science, 8, pp.1-16. https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.634541/full Blanchet, M.A., Vincent, C., Womble, J., Steingass, S. and Desportes, G., (2021). Harbour Seals: Population Structure, Status, and Threats in a Rapidly Changing Environment. In Oceans (Vol. 2, No. 1, pp. 41-63).https://www.mdpi.com/2673-1924/2/1/3 Womble, J.N., Ver Hoef, J.M, Mathews, E.A., Gende, S.M. (2020). Calibrating and adjusting counts of harbor seals in a tidewater glacier fjord to estimate abundance and trends 1992-2017. Ecosphere 11(4), p.e03111. https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.3111 Womble, J.N. 2012. Foraging ecology, diving behavior, and migration patterns of harbor seals (Phoca vitulina richardii) from a glacial fjord in Alaska in relation to prey availability and oceanographic features. Ph.D. Dissertation. Oregon State University, Corvallis, Oregon. Blundell, G.M., Womble, J.N., Pendleton, G.W., Karpovich, S.A., Gende, S.M., Herreman, J.K. (2011) Use of glacial ice and terrestrial habitats by harbor seals in Glacier Bay, Alaska: costs and benefits. Marine Ecology Progress Series 429:277- 290. https://www.int-res.com/articles/meps_oa/m429p277.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 Womble, J.N., Pendleton, G.W., Mathews, E.A., Blundell, G.M., Bool, N.M., Gende, S.M. (2010) Harbor seal decline continues in the rapidly changing landscape of Glacier Bay National Park, Alaska, 1992-2008. Marine Mammal Science 26:686-697https://onlinelibrary.wiley.com/doi/10.1111/j.1748-7692.2009.00360.x?msockid=14da1e5b94b961b802740be595036098 Womble, J.N., Pendleton, G.W., Mathews, E.A., Gende S.M. (2015). Status and trend of harbor seals at terrestrial sites in Glacier Bay National Park from

This dataset supports efforts to estimate the abundance and trends in population size of Alaska harbor seals. Annual surveys of harbor seal populations are fundamental to estimation of seal abundance, distribution, and trends, which in turn are essential for stock assessment, conservation, and management. The most feasible approach to determining harbor seal distribution and abundance is to use aircraft to count seals when they haul out of the water and are visible. Harbor seals in Alaska occupy a geographically extensive range from approximately long. 172ºE to 130ºW (over 3,500 km east to west) and from lat. 51ºN to 61.5ºN (over 1,000 km north to south). Estimation of the abundance of harbor seals statewide requires broad-scale aerial surveys and these surveys have been conducted by NOAA Fisheries, the Alaska Department of Fish and Game, and other collaborators since the early 1980s. This dataset reflects counts of harbor seals from surveys conducted in Alaska between 1998 and 2002. During this period, the range of Alaska harbor seals was divided into five survey regions and only one region was surveyed each year. This approach allowed observers to survey the entire coastline of each region, sometimes twice per year, to identify new harbor seal haul-out sites, and for individual haul-out sites to be surveyed multiple times in a given year, weather permitting. This intensive effort produced a lot of data for each region in a given year, but surveying the entire range to produce state-wide abundance and trend estimates required a period of 5 years.

Data were collected during aerial surveys carried out at low tides in June and August 1994-1997, 2000 and 2001. June and August are respectively pupping and moulting seasons, when the haulout sites are intensively used by seals. Features in this layer show the Grey seal distribution and mean abundance for all aerial surveys (tables 4 and 6, figures 4 and 6 from Robillard et al. 2005). In the estuary, areas of high abundance have more than 25 individuals, areas of medium abundance have between 5 and 25 individuals and areas of low abundance have fewer than 5 individuals. In the Gulf, areas of high abundance have more than 70 individuals and areas of medium to low abundance have fewer than 70 individuals. Data are valid only during summer because Grey seals in the Estuary and northern Gulf migrate to the southern Gulf of St. Lawrence in the fall. These seals will spend the winter on Sable Island, on the ice shelf in the Northumberland Strait or on neighboring islands. During the summer, in the Estuary and the Gulf of St. Lawrence, its distribution is not uniform between the different concentration areas identified, but it is similar between June and August. However, there are some areas where Grey seals are more abundant in August than in June. Abundance classes are arbitrary but fit with the published results of haul-out sites utilization from Robillard et al. (2005). Data shown are a picture of the situation in 2005 because it is the most recent mapping available for this species. Data sources and references: Lavigueur, L., Hammill, M.O., and Asselin, S. 1993. Distribution et biologie des phoques et autres mammifères marins dans la région du parc marin du Saguenay. Rapp. manus. can. sci. halieut. aquat. 2220: vi + 40. Lesage, V., and Hammill, M.O. 2001. The status of the grey seal, Halichoerus grypus, in the Northwest Atlantic. Can. Field-Nat. 115(4): 653-662. Robillard, A., V. Lesage, and M.O. Hammill. 2005. Distribution and abundance of harbour seals (Phoca vitulina concolor) and grey seals (Halichoerus grypus) in the Estuary and Gulf of St. Lawrence, 1994–2001. Can. Tech. Rep. Fish. Aquat. Sci. 2613: 152 pp.

Most of the data were collected during aerial surveys carried out at low tides during June and August 1994-1997, 2000 and 2001. June and August are respectively pupping and moulting seasons, when the haulout sites are intensively used by seals. Features in this layer show the Harbour seal distribution and the mean abundance for all aerial surveys (tables 3 and 5, figures 3 and 5 from Robillard et al. 2005). In the estuary, areas of high abundance have more than 30 individuals, areas of medium abundance have between 10 and 30 individuals and areas of low abundance have fewer than 10 individuals. In the Gulf, areas of high abundance have more than 50 individuals and areas of medium to low abundance have fewer than 50 individuals. Unpublished data obtained from Parks Canada and Sepaq were also used to identify important haulout areas in the Saguenay Fjord sector and in Pointe-aux-Vaches tidal flat sectors, which have been categorized in this dataset as high abundance areas. Data are valid only during summer (except for the Pointe-aux-Vaches flats identified as mainly frequented in autumn by Parc Canada), because spring and fall distributions of the Harbour seal are unknown. Data shown in the Estuary and the Gulf of St. Lawrence are a picture of the situation in 2005 because it is the most recent mapping available for this specie. The distribution of the Harbour seal is non-uniform among the different concentration areas but is similar between June and August. However, Harbour seals tend to decrease their presence along the south shore and the Lower Estuary in August to the benefit of the Saguenay River colonies. Abundance classes are arbitrary but fit with the published results of haulout site utilization from Robillard et al. (2005). Data sources : Parks Canada. 2021. Personal communication. Harbor seal monitoring data on the Pointe-aux-Vaches tidal flat. Parks Canada and SÉPAQ, 2020. Données du suivi du phoque commun dans le fjord du Saguenay. Unpublished data. Robillard, A., V. Lesage, and M.O. Hammill. 2005. Distribution and abundance of harbour seals (Phoca vitulina concolor) and grey seals (Halichoerus grypus) in the Estuary and Gulf of St. Lawrence, 1994–2001. Can. Tech. Rep. Fish. Aquat. Sci. 2613: 152 pp.

Aerial surveys were conducted during 1983–2006 in the Ketchikan, Sitka, Kodiak, and Bristol Bay areas of Alaska to estimate trends in abundance of harbor seals.