Guadalupe Island IMMA

Size in Square Kilometres

2 754 km2

Qualifying Species and Criteria

Guadalupe fur seal – Arctocephalus philippii townsendi 

Criterion A; B (1, 2); C (1, 2)

Northern elephant seal – Mirounga angustirostris 

Criterion A; B (1); C (1)

 Cuvier’s beaked whale – Ziphius cavirostris

Criterion B (1); C (1)

Marine Mammal Diversity 

Criterion D (2)

Zalophus californianus, Tursiops truncatus, Lagenorhynchus obliquidens, Delphinus delphis, Megaptera novaeangliae, Balaenoptera musculus, Orcinus orca, Balaenoptera edeni, Balaenoptera physalus, Globicephala macrorhynchus, Grampus griseus, Physeter macrocephalus

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Guadalupe Island is a Biosphere Reserve, located 250km West of the Baja California Peninsula, Mexico. It is surrounded by nutrient rich waters, including canyons that reach depths of up to 4,000 m. Guadalupe island and its islets were declared a Biosphere Reserve (BR) due to their biological and ecological relevance on April 25, 2005. It is one of the most biologically important sites in Mexico. Because of its isolation and the low impact of current anthropogenic activities, Guadalupe Island offers an opportunity to study the processes of regeneration, succession, and colonization. This island is the only breeding site for Guadalupe fur seals (Arctocephalus philippii townsendi), as well as the main breeding location in Mexico for northern elephant seals (Mirounga angustirostris). A small colony of California sea lions (Zalophus californianus) is also found on this island. A resident population of Cuvier’s beaked whales (Ziphius cavirostris) forages and reproduces in this area, and around 13 cetacean species use the area regularly.

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

The Guadalupe fur seal (Arctocephalus philippii townsendi) was severely exploited in the late 18th and early 19th centuries, being declared as commercially extinct in 1897 (Hubbs, 1956). Its pre-exploitation population size reached 100,000-200,000 individuals (Hubbs, 1979) with a distribution from the Revillagigedo Islands, Mexico, to areas offshore from Washington State, USA (Etnier, 2002). Currently its only remaining well-established breeding site is Guadalupe Island, mainly along the east side of the island, and especially on the southern portion, called Punta Sur, where the largest aggregation of fur seals is located within the area. There are also non-breeding sites on San Benito and in the Gulf of California (García-Aguilar et al., 2018a; Elorriaga-Verplancken et al., 2021; Gutiérrez-Ozuna et al., 2021; Gálvez et al., 2022). The species’ current abundance is 57,199-72,631 individuals (Juárez-Ruiz et al., 2022), still under recovery and impacted by an unusual mortality event from 2015 to 2021 along the California, Washington, and Oregon coastlines (NOAA-Fisheries, 2021) as well as a 2015-2016 El Nino associated decline at San Benito (Elorriaga-Verplancken et al., 2016). These warm anomalies can change Guadalupe fur seal movement patterns due to changes in the availability of prey in the food web (Amador-Capitanachi et al., 2020). Although this fur seal species is currently classified as Least Concern (LC) on the IUCN Red List, it is ‘Endangered’ under Mexican Law (Norma-Oficial-Mexicana-NOM-059-SEMARNAT-2010) and ‘Threatened’ under the U.S. Endangered Species Act of 1973.

The northern elephant seal (Mirounga angustirostris) colony on Guadalupe Island is one of the three main breeding locations (Guadalupe, San Benito Archipelago, and Cedros Island) off the Baja California Peninsula (Arias del Razo et al., 2017). The abundance of northern elephant seals in Baja California colonies, including Guadalupe Island, has decreased during the last three decades, probably as a probable consequence of increased local air temperatures. An indicator of this decline is that the contribution of the Baja California (Mexico) colonies in terms of number of births for the entire species decreased from 25% in the early 1990s to 11% in 2009 (García-Aguilar et al., 2018b). This species is classified as ‘Threatened’ under Mexican Law (Norma-Oficial-Mexicana-NOM-059-SEMARNAT-2010).

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

Northern elephant seals have a small resident colony on the island, which has been estimated to contain around 12,000 individuals (García-Aguilar et al., 2018b ; Arias-del-Razo et al., 2017) concentrated on the northern portion of Guadalupe. This represents a significant number in relation to the population of around 201,000 in California (Lowry et al., 2014) and around 22,000 on the Baja California Peninsula, Mexico (García-Aguilar et al., 2018b). Even though they are mainly present in winter and spring-summer for breeding and moulting, respectively, they are present on the island year-round (Programa de Manejo- Reserva de la Biosfera Isla Guadalupe, 2013). Adult female and male northern elephant seals perform two annual migrations off Guadalupe Island to the northern Pacific, where their main foraging grounds are located; one is accomplished after the breeding season in winter and another one after the moulting season in spring-autumn (Robinson et al., 2012).

Preliminary photo-identification studies combined with the data collected by Cárdenas-Hinojosa et al. (2015), indicated a total of 87 individual Cuvier’s beaked whales (Ziphius cavirostris) are likely resident in the waters around the island. More than half of these photo-identified individuals were seen more than once (n= 57) (Cárdenas-Hinojosa et al., 2022). Furthermore, long-term acoustic monitoring using a High-frequency Acoustic Recording Package (HARP) deployed from November 2018 to October 2020 in Bahía Norte, revealed year-round presence of Cuvier’s beaked whales around Guadalupe Island (Cárdenas-Hinojosa et al., 2015; 2022).

Sub-criterion B2: Aggregations

The largest aggregation of Guadalupe fur seals anywhere in the species’ range is on the east coast of Guadalupe Island. This represents almost the entire extant population for the species. More than 99% of all births take place on this island. Hence, even though there are non-breeding Guadalupe fur seal sites elsewhere (Elorriaga-Verplancken et al., 2021; Gutiérrez-Osuna et al., 2021; Gálvez et al., 2022), all individuals are part of the Guadalupe Island population, since they were born on this island (García-Aguilar et al., 2018a). Most of the colony remains on the island year-round, although male Guadalupe fur seals seem to perform migrations off Guadalupe Island once the breeding season is over (Pierson, 1987; Gallo-Reynoso, 1994). Additionally, juvenile, subadult, and adult males also perform seasonal migrations to the San Benito Archipelago (Aurioles et al., 2010; Elorriaga-Verplancken et al., 2016) and to the Gulf of California (Elorriaga-Verplancken et al., 2021; Gálvez et al., 2022).

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas

Guadalupe Island is the only known reproductive site for the Guadalupe fur seals, with reproductive areas located along the entire east coast (Gallo-Reynoso, 1994; García-Aguilar et al., 2018 ; Juárez-Ruiz et al., 2022). The number of Guadalupe fur seal pups born on this island is related to annual shifts in sea surface temperature. Numbers ranged between ~12,500 and 15,400 in 2018-2019 (Juárez-Ruiz et al., 2022). Northern elephant seals also breed on Guadalupe Island and this colony on the island represents around 60% of the births (around 3,000 in 2009) in the Baja California (Mexico) population (García-Aguilar et al., 2018b). Resident Cuvier’s beaked whales also reproduce in the area (Cárdenas-Hinojosa et al., 2016). Surveys conducted from October 2016 to February 2021 documented a total of 384 sightings, of which 93 were of mother and calf pairs (Cárdenas-Hinojosa et al., 2022).

Sub-criterion C2: Feeding Areas

Guadalupe fur seals undertake foraging trips around Guadalupe Island. Preliminary data suggest that a foraging area around Guadalupe Island is occupied in around 40% of the time by this species (Amador-Capitanachi, 2018). Like other otariids (Boness and Bowen, 1996), adult females that give birth every summer, must alternate maternal care with localised foraging trips during the 8–9-month lactation period until pups are weaned (Gallo-Reynoso, 1994; Amador-Capitanachi, 2018). The Guadalupe fur seal diet is primarily teutophagous in this region, mostly comprising jumbo squid (Dosidicus gigas) and opalescent squid (Doryteuthis opalescens), as well as other squid species and members of the lantern fish (Myctophidae) family (Amador-Capitanachi et al., 2020).

Criterion D: Special Attributes

Sub-criterion D2: Diversity

High levels of productivity and a wide range of habitats from beaches to deep near-shore canyons support a wide range of marine mammal species off Guadalupe Island. Perhaps the most notable species is the Guadalupe fur seal, which resides in the IMMA year-round and breeds on the island. Cuvier’s beaked whales and northern elephant seals are also present throughout most of the year, as are California sea lions. Other cetacean species that are regularly observed in the Guadalupe Island IMMA include fin whales (Balaenoptera physalus), blue whales (Balaenoptera musculus), Bryde’s whales (Balaenoptera edeni), humpback whales (Megaptera novaeangliae), common bottlenose dolphins (Tursiops truncatus), common dolphins (Delphinus delphis), short-finned pilot whales (Globicephala macrorhynchus), Risso’s dolphins (Grampus griseus), Pacific white-sided dolphins (Lagenorhynchus obliquidens), killer whales (Orcinus orca), sperm whales (Physeter macrocephalus), as well as dwarf and pygmy sperm whales (Kogia spp) (Gallo-Reynoso and Figueroa-Carranza, 2005 ; Programa de Manejo- Reserva de la Biosfera Isla Guadalupe, 2013; Cárdenas-Hinojosa, unpublished data).

Supporting Information

Amador-Capitanachi, M. J. 2018. ‘Variabilidad en el nicho isotópico (2013-2016) y análisis del desplazamiento mediante telemetría en el lobo fino de Guadalupe (Arctocephalus philippii townsendi)’ [‘Variability in the isotopic niche (2013-2016) and analysis of the movements by telemetry in the Guadalupe fur seal (Arctocephalus philippii townsendi)’] (Master’s thesis). Centro Interdisciplinarion de Ciencias Marinas CICIMAR-IPN, La Paz, Mexico.

Amador-Capitanchi, M.J., Moreno-Sánchez, X., Ventura-Domínguez, P., Juárez-Ruíz, A., González- Rodríguez, E., Gálvez, C., Norris, T. and Elorriaga-Verplancken, F. 2020. ‘Ecological implications of unprecedented warm water anomalies on interannual prey preferences and foraging areas of Guadalupe fur seals’. Marine mammal Science, 1-17.

Arias-Del-Razo, A., Schramm Y., Heckel, G., Milanés-Salinas, A., García-Capitanachi, B., Lubinsky-Jinich, D. and Franco-Ortiz, M. 2017. ‘Distribution of four pinnipeds (Zalophus californianus, Arctocephalus philippii townsendi, Phoca vitulina richardii, and Mirounga angustirostris) on islands off the west coast of the Baja California Peninsula, Mexico’. Aquatic Mammals, 43: 40-5.

Aurioles-Gamboa, D., Elorriaga-Verplancken, F.R. and Hernández-Camacho, C.J. 2010. ‘The current population of Guadalupe fur seal in San Benito Islands, Mexico’. Marine Mammal Science, 26: 402-408.

Boness, D.J. and Bowen, W. D. 1996. ‘The evolution of maternal care in pinnipeds’. Bioscience, 46: 645-654.

Cárdenas-Hinojosa, G., Hoyos-Padilla, M. and Rojas-Bracho, L. 2015. ‘Occurrence of Cuvier’s beaked whales (Ziphius cavirostris) at Guadalupe Island, Mexico, from 2006 through 2009’. Latin American Journal of Aquatic Mammals, 10 : 38-47.

Cárdenas-Hinojosa, G., Trickey, J., Schorr, G., Rone, B., Falcone, E., Huerta-Patiño, R. Rojas-Bracho, L., López-Arzate, D. and Bonilla-Garzón, A. 2022. ‘An Update on the Resident Population of Cuvier´s Beaked Whales (Ziphius cavirostris) of Guadalupe Island, México’. Oral presentation 24th Conference on the Biology of Marine Mammals. Society for Marine Mammalogy.

Elorriaga-Verplancken, F.R., Sierra-Rodríguez, G.E., Rosales-Nanduca, H., Acevedo-Whitehouse, K. and Sandoval-Sierra, J. 2016. ‘Impact of the 2015 El Niño-Southern Oscillation on the abundance and foraging habits of Guadalupe fur seals and California sea lions from the San Benito Archipelago, México’. PLoS ONE, 11:: e0155034.

Elorriaga-Verplancken, F.R., Paniagua-Mendoza, A., Hernández-Camacho, C.J., Webber, M.A., Cruz-Vallejo, R., Nevels, C.R. and Gónzález-López, I. 2021. ‘A new Guadalupe fur seal colony in the Gulf of California? Ecological and conservation implications’. Aquatic Mammals. 47: 1-9.

Etnier, M. A. 2002. ‘Occurrence of Guadalupe fur seals (Arctocephalus townsendi) on the Washington coast over the past 500 years’. Marine Mammal Science, 18: 551–556.

Gálvez, C., Pérez-Puig, H. and Elorriaga-Verplancken, F. R. 2022. ‘Northernmost habitat range of Guadalupe fur seals (Arctocephalus townsendi) in the Gulf of California, Mexico’. Aquatic Mammals, 48: 222-233.

Gallo-Reynoso, J.P. 1994. ‘Factors affecting the population status of Guadalupe fur seal, Arctocephalus townsendi (Merriam 1897) at Isla De Guadalupe, Baja California, Mexico (Ph.D. dissertation)’. University of California, Santa Cruz, CA.

Gallo-Reynoso, J.P. and Figueroa-Carranza, A.L. 2005. ‘Los cetáceos de Isla Guadalupe’. In : K. Santos del Prado and E. Peters (eds.) Isla Guadalupe, restauración y conservación, pp. 203-217. SEMARNAT-INE, CICESE, GECI, SEMAR, Mexico.

García-Aguilar, M.C., Elorriaga-Verplancken, F.R., Rosales-Nanduca, H. and Schramm, Y. 2018a. ‘Population status of the Guadalupe fur seal (Arctocephalus townsendi)’. Journal of Mammalogy, 99: 1522-1528.

García-Aguilar, M.C., Turrent, T., Elorriaga-Verplancken, F.R., Arias-Del-Razo, A. and Schramm, Y. 2018b. ‘Climate change and the northern elephant seal (Mirounga angustirostris) population in Baja California, Mexico’. Plos One, 13(2): e0193211.

Gutiérrez‐Osuna, M. del C., Díaz‐Gaxiola, J.M., Trites, A.W. and Hernández‐Camacho, C.J. 2021. ‘New colony of Guadalupe fur seals (Arctocephalus townsendi) discovered on El Farallón de San Ignacio Island, Gulf of California’. Marine Mammal Science, 38: 374-382.

Hubbs, C.L. 1956. ‘Back from oblivion? Guadalupe fur seal: still a living species’. Pacific Discovery, 9: 14-21.

Hubbs, C.L. 1979. ‘Guadalupe fur seal. Mammals in the seas’. Pinniped species summaries and report on sirenians. FAO Fisheries Series, 5: 24-27.

Juárez-Ruiz, A., Pardo, M.A., Hernández-Montoya, J., Elorriaga-Verplancken, F.R., Milanés-Salinas, M.A., Norris, T., Beier, E. and Heckel, G. 2022. ‘Guadalupe fur seal pup production predicted from annual variations of sea surface temperature in the southern California Current Ecosystem’. ICES Journal of Marine Science, fsac097.

Lowry, M.S, Condit R., Hatfield, B., Allen, S.G., Berger, R., Morris, P.A., Le Bœuf, B.J. and Reiter, J. 2014. ‘Abundance, distribution, and population growth of the northern elephant seal (Mirounga angustirostris) in the United States from 1991 to 2010’. Aquatic Mammals, 40: 20-31.

NOAA Fisheries. 2021. ‘Guadalupe fur seal unusual mortality event in California’. Available at : (Accessed: 2 June 2022).

Norma-Oficial-Mexicana. 2010. NOM-059-SEMARNAT-2010, Protección Ambiental—Especies nativasde México de flora y fauna silvestre. ‘Categorías de riesgo y especificaciones para su inclusión, exclusión o cambio. Lista de especies en riesgo. SEMARNAT’. Diario oficial de la Federación [NOM-059-SEMARNAT-2010, Environmental protection—Native species of Mexico of wild flora and fauna. Risk categories and specifications for inclusion, exclusion or change. List of species at risk. SEMARNAT. Official Journal of the Federation].

Parés-Sierra, A., López, M. and Pavía, E. G. 1997. ‘Oceanografía física del Océano Pacífico Nororiental’. In: M. Lavin (ed.) Contribuciones a la Oceanografía Física en México, pp. 1-24. Centro de Investigación Científica y de Educación Superior de Ensenada.

Pierson, M.O. 1987. ‘Breeding behavior of the Guadalupe fur seal, Arctocephalus townsendi’. In: J.P. Croxall, and R. L. Gentry (eds.) Status, biology, and ecology of fur seals, pp 83-94. NOAA Technical Report, National Marine Fisheries Service, USA.

Programa de Manejo de la Reserva de la Biosfera Isla Guadalupe. 2013. Secretaría de Medio Ambiente y Recursos Naturales. 236 pp.

Robinson, P.W., Costa, D.P., Crocker, D.E., Gallo-Reynoso, J.P., Champagne, C.D., Fowler, M.A. and Kuhn, C.E. 2012. ‘Foraging behavior and success of a mesopelagic predator in the northeast Pacifc Ocean: insights from a data-rich species, the northern elephant seal’. PLoS ONE, 7:e36728.


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