Otarie de Wollebaek
Zalophus wollebaekiSivertsen, 1953
1 photo · Licences CC (Wikimedia Commons / iNaturalist)Click pour agrandir
Pays · région · aire protégée · écorégion · biome
Chargement du graphe…
Indicateurs du réseau écologique
Comment lire ce graphe
Ce graphe représente les interactions écologiques documentées entre Zalophus wollebaeki et d'autres espèces, à partir de la base GloBI (Global Biotic Interactions, agrégation mondiale de la littérature scientifique) — source principale, complétée par d'autres jeux de données d'interactions agrégés par Ontologia. Il faut le comprendre comme une carte du savoir documenté, pas une carte de la réalité écologique exhaustive.
Limites principales
- Incomplet. La majorité des interactions écologiques en milieu naturel n'ont jamais été publiées. Une espèce sans liens visibles n'est pas isolée — elle est probablement mal étudiée.
- Biais publication pharmaco-agronomique. La littérature des interactions est polarisée par les enjeux économiques et sanitaires : parasitism / pathogen sur-pondéré sur les mammifères (recherche zoonoses, vecteurs), herbivory sur-pondéré sur les insectes phytophages (entomologie agronomique). À l'inverse, mutualisms, commensalisms et interactions sol/microbiote sont sous-cités. Conseil de lecture : sur les hubs mammifères ou les insectes ravageurs de culture, lire les arêtes parasitism / herbivory dominantes relativement au contexte de littérature, pas comme une mesure d'intensité écologique brute. Détails §10.1.
- Biaisé vers les espèces étudiées. Quelques espèces (oiseaux communs, abeille mellifère, espèces modèles) concentrent disproportionnellement plus d'interactions documentées. Notre score composite ajoute un malus aux hubs de littérature pour atténuer cette dominance visuelle.
- Interactions documentées globalement. Toutes les espèces affichées sont observées en France métropolitaine (les observations sont filtrées sur le territoire métropolitain), mais les interactions entre elles proviennent de la littérature scientifique mondiale. Une interaction documentée à l'étranger peut ne pas se réaliser à l'identique sur votre territoire. Le filtre « restreindre à ma commune » tient compte de la co-occurrence spatiale locale mais ne garantit pas l'interaction effective.
- Sans dimension temporelle. Les variations saisonnières (migration, floraison, cycle de vie) ne sont pas modélisées.
- Force d'interaction approximative. L'épaisseur des liens reflète le nombre de fois où l'interaction a été rapportée dans la littérature, pas son importance écologique réelle.
Comment nous sélectionnons les espèces affichées
Le graphe affiche au plus 31 nœuds par fiche (1 centre + 15 bulles depth=1 + 15 partenaires depth=2). Le serveur sélectionne intelligemment :
- Bulles famille créées si une cascade taxonomique existe ou si ≥3 espèces directement documentées partagent une même famille — les espèces sont absorbées dans la bulle (pas de doublon visuel)
- Espèces individuelles uniquement quand <3 dans une famille (sans cascade) — relations directes documentées
- Pas d'espèces inférées affichées en doublon — les cascades sont représentées via les bulles famille uniquement
- Partenaires depth=2 sélectionnés via algo priorité : candidat partagé par ≥2 docs de la famille (food web central) → reliant entre bulles → top sum_obs en dernier recours
- Sous-types GloBI traduits en français au survol de la flèche (chasse, parasite, parasitoïde, mycorhize…)
Le toggle Profondeur 1 ↔ 2 client-side cache ou affiche les partenaires depth=2 sans refetch. Filtres règne, type d'interaction, ordres/familles, patrimoniales et commune recalculent côté serveur (slow path live ~1-2 s).
Indicateurs avancés (mode expert) : Modularité Q (Newman 2006, PNAS), communautés (Louvain, Blondel et al. 2008, J. Stat. Mech.), nestedness NODF (Almeida-Neto et al. 2008, Oikos).
Source : GloBI · TAXREF v18 (INPN/MNHN) · BDC-Statuts · Wikidata
83 partenaires écologiques documentés directement dans GloBI.
Partenaires
83
Espèces avec interactions documentées
Types d'interactions
6
Prédation, pollinisation, parasitisme…
Connectance
0.068
Densité des liens dans le sous-graphe affiché
Rang animalia
96 %
Percentile vs ensemble des animalia
Liste rouge IUCN
EN · En dangercritères A2ab↘Décroissante- Évaluation
- 2015 · v3.1
- Altitude
- 0 – 5 m
- Profondeur
- 584 – 0 m
État de la populationTexte officiel évaluation IUCNExpert
Age-structure data are not available for the Galápagos Sea Lion population, so the generation time and the fraction mature cannot be calculated reliably. However, with sexual maturity attained at about six years of age and a maximum longevity of approximately 20 years, the average age of reproducing individuals should be around 10 years. It is likely that about two-thirds of all animals in the population are mature.
In 1978, Galápagos Sea Lions were estimated to number about 40,000 individuals (Trillmich 1979). This estimate was based on a nearly complete survey of the coastlines of all Galapagos Islands conducted by observers onshore and in boats nearshore. This resulted in an actual count of 9,093 individuals. The number counted was expanded to account for animals missed by observers on boats and to account for animals not onshore at the time of the counts. In November 2001, 7,942 Sea Lions were counted at haulouts and rookeries in the Galápagos Islands (Alava and Salazar 2006). By correcting for the probability that animals could be seen at a distance, total abundance was estimated to be 14-16,000. The corresponding number of mature individuals was likely about 26,400 in 1978 and 9,200-10,600 in 2001, which indicates a substantial reduction of about 60-65% in population size of the Galápagos Sea Lion. No further estimates of total population size have been made since 2001. Census data from a colony in the centre of the range (on the islet of Caamaño near Santa Cruz Island) covering the years from 2003 to 2013 showed no significant trend in total numbers of Sea Lions counted (mean ± SD; 244 ± 63) nor in the number of pups born (mean 103 ± 34.7), but substantial fluctuations around the mean. This variability suggests that single counts as represented by the 1978 and 2001 census may be misleading about trends in total Sea Lion numbers.
The available data suggest that the Galápagos Sea Lion population declined greatly between 1978 and 2001, and suggest that it has not recovered since then. If the number of adults in 2014 is still about 9,200-10,600 that would be a reduction of 60-65% in 36 years (3.6 generations). Assuming an exponential decline pattern between 1978 and 2001 (with an annual decline of 3.9%), and a relatively stable population from 2001-2014, this would still represent a reduction of >50% (49-54%) over the last three generations (1984-2014). The causes of the reduction are partly understood, have not ceased, and may not be reversible.
In 1978, Galápagos Sea Lions were estimated to number about 40,000 individuals (Trillmich 1979). This estimate was based on a nearly complete survey of the coastlines of all Galapagos Islands conducted by observers onshore and in boats nearshore. This resulted in an actual count of 9,093 individuals. The number counted was expanded to account for animals missed by observers on boats and to account for animals not onshore at the time of the counts. In November 2001, 7,942 Sea Lions were counted at haulouts and rookeries in the Galápagos Islands (Alava and Salazar 2006). By correcting for the probability that animals could be seen at a distance, total abundance was estimated to be 14-16,000. The corresponding number of mature individuals was likely about 26,400 in 1978 and 9,200-10,600 in 2001, which indicates a substantial reduction of about 60-65% in population size of the Galápagos Sea Lion. No further estimates of total population size have been made since 2001. Census data from a colony in the centre of the range (on the islet of Caamaño near Santa Cruz Island) covering the years from 2003 to 2013 showed no significant trend in total numbers of Sea Lions counted (mean ± SD; 244 ± 63) nor in the number of pups born (mean 103 ± 34.7), but substantial fluctuations around the mean. This variability suggests that single counts as represented by the 1978 and 2001 census may be misleading about trends in total Sea Lion numbers.
The available data suggest that the Galápagos Sea Lion population declined greatly between 1978 and 2001, and suggest that it has not recovered since then. If the number of adults in 2014 is still about 9,200-10,600 that would be a reduction of 60-65% in 36 years (3.6 generations). Assuming an exponential decline pattern between 1978 and 2001 (with an annual decline of 3.9%), and a relatively stable population from 2001-2014, this would still represent a reduction of >50% (49-54%) over the last three generations (1984-2014). The causes of the reduction are partly understood, have not ceased, and may not be reversible.
Menaces identifiées(6 menaces classées CMP-IUCN)
11_5Other impactsRapid DeclinesWhole (>90%)Ongoing8_1_1Unspecified speciesCausing/Could cause fluctuationsMajority (50-90%)Ongoing8_2_1Unspecified speciesCausing/Could cause fluctuationsMinority (<50%)Ongoing8_1_2Named speciesNegligible declinesMinority (<50%)Ongoing8_1_2Named speciesNegligible declinesMinority (<50%)Ongoing9_4Garbage & solid wasteNegligible declinesMajority (50-90%)Ongoing
Description complète des menacesTexte détaillé évaluation IUCNExpert
Population abundance has fluctuated widely due to die-offs and cessation of reproduction during strong El Niño events, when marine productivity collapses (Trillmich and Limberger 1985, Trillmich and Dellinger 1991). During strong El Niños, 100% of pups, 50% of yearlings, and substantial numbers of adults may die (Limberger 1985; Trillmich and Dellinger 1991). Smaller El Niños likely have more subtle, but possibly still significant, effects on productivity and survival. Epidemics of unknown causation have occurred during El Niño events, adding to the stress on Sea Lions from low food abundance.
Oceanographers differ in their predictions of how the frequency and intensity of El Niño events may change with climate warming. Cai et al. (2014) suggest that the total number of El Niño events will decrease slightly, but the total number of extreme events will double as global warming continues. In contrast, Santoso et al. (2013) predict a doubling of the frequency of El Niño events with global warming. In the historical long-term perspective offered by Cobb et al. (2014) the frequency of El Niño during the last 50 years is unusually high, but still within the range of variability observed over the last 7,000 years. The most likely projection seems to be that El Niño events will be more frequent, and perhaps stronger, in the immediate future. In their review of otariid extinctions, Gerber and Hilborn (2001) conclude that for species subject to El Niño impacts, "the concern about species recovery should focus on changes in frequency of El Niño events."
Infectious diseases occur commonly in pinnipeds and may have substantial impacts on their populations. Frequent direct contact between Sea Lions and domestic dogs in the settlements on San Cristobal, Santa Cruz and Isabela islands present a great danger of disease transmission. A viral outbreak (of canine distemper?) occurred in 2001 in which 569 dogs either died or were euthanized, and it was recommended that all dogs on the islands be vaccinated to reduce the risk of transmission to Sea Lions (Salazar et al. 2001). The identity of the virus has not been confirmed. The populations near settlements were shown to express higher immune activity than more isolated ones (Brock et al. 2013).
Plastic refuse drifting at sea and on shore is becoming an increasing problem, frequently entangling Sea Lions (Alava and Salazar 2006). Cargo ships running aground (like the "Jessica" in 2001) may lead to oil spills that could gravely affect pups onshore (in particular close to the harbours of San Cristobal and Puerto Ayora) and foraging adults.
Oceanographers differ in their predictions of how the frequency and intensity of El Niño events may change with climate warming. Cai et al. (2014) suggest that the total number of El Niño events will decrease slightly, but the total number of extreme events will double as global warming continues. In contrast, Santoso et al. (2013) predict a doubling of the frequency of El Niño events with global warming. In the historical long-term perspective offered by Cobb et al. (2014) the frequency of El Niño during the last 50 years is unusually high, but still within the range of variability observed over the last 7,000 years. The most likely projection seems to be that El Niño events will be more frequent, and perhaps stronger, in the immediate future. In their review of otariid extinctions, Gerber and Hilborn (2001) conclude that for species subject to El Niño impacts, "the concern about species recovery should focus on changes in frequency of El Niño events."
Infectious diseases occur commonly in pinnipeds and may have substantial impacts on their populations. Frequent direct contact between Sea Lions and domestic dogs in the settlements on San Cristobal, Santa Cruz and Isabela islands present a great danger of disease transmission. A viral outbreak (of canine distemper?) occurred in 2001 in which 569 dogs either died or were euthanized, and it was recommended that all dogs on the islands be vaccinated to reduce the risk of transmission to Sea Lions (Salazar et al. 2001). The identity of the virus has not been confirmed. The populations near settlements were shown to express higher immune activity than more isolated ones (Brock et al. 2013).
Plastic refuse drifting at sea and on shore is becoming an increasing problem, frequently entangling Sea Lions (Alava and Salazar 2006). Cargo ships running aground (like the "Jessica" in 2001) may lead to oil spills that could gravely affect pups onshore (in particular close to the harbours of San Cristobal and Puerto Ayora) and foraging adults.
Habitats préférentiels (classification IUCN)
10_1Marine Oceanic - Epipelagic (0-200m)★12_1Marine Intertidal - Rocky Shoreline★13_1Marine Coastal/Supratidal - Sea Cliffs and Rocky Offshore Islands★9_1Marine Neritic - Pelagic★10_2Marine Oceanic - Mesopelagic (200-1000m)
Mesures de conservation recommandéesStratégies de conservation IUCNExpert
The Galápagos Sea Lion population lives in the Galápagos Archipelago, which is an Ecuadorian National Park surrounded by a marine resources reserve. Tourism occurs on a large scale, but is largely controlled to protect wildlife from disturbance. Local fishing is controlled by the National Park authorities. Unfortunately, despite a quarantine system introduction of domestic animals from the mainland is still occurring occasionally.
Actions de conservation (2)Conservation Actions Classification Scheme — IUCNExpert
2_1Site/area management3_2Species recovery
Stress écologiques (11)Stresses Classification — IUCNExpert
1_1Ecosystem conversion1_2Ecosystem degradation2_1Species mortality2_1Species mortality2_1Species mortality2_1Species mortality2_1Species mortality2_2Species disturbance2_3_7Reduced reproductive success2_3_7Reduced reproductive success2_3_7Reduced reproductive success
Priorités de recherche (4)Research Needed Classification — IUCNExpert
1_2Population size, distribution & trends1_5Threats1_6Actions3_1Population trends
Niche IUCN globaleRealms · Systems · LMEs · Growth forms · FAOs — biogéographie IUCNExpert
Royaumes biogéographiques
Neotropical
Systèmes (terrestre/eau douce/marin)
TerrestrialMarine
Zones de pêche FAO
Pacific - southeast
Références bibliographiques (28)Sources scientifiques de l'évaluation IUCNExpert
- IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015.2. Available at: <a href="www.iucnredlist.org">www.iucnredlist.org</a>. (Accessed: 23 June 2015).
- Cai, W., Borlace, S., Lengaigne, M., van Rensch, P., Collins, M., Vecci, G., Timmermann, A., Santoso, A., McPhaden, M.J., Wu, L., England, M.H., Guojian, W. and Jin, F-F. 2014. Increasing frequency of extreme El Niño events due to greenhouse warming. <i>Nature Climate Change</i> 4: 111-116.
- Páez-Rosas, D., Riofrío-Lazo, M. and Aurioles-Gamboa, D. 2014. Flexibility in the foraging strategies of the Galapagos sea lion inferred from a multiple approach analysis. In: J. Denkinger and L. Vinueza (eds), <i>The Galapagos Marine Reserve</i>, pp. 71-80. Springer Verlag, New York.
- Trillmich, F., Jeglinski, J.W.E., Meise, K. and Piedrahita, P. 2014. The Galapagos sea lion: Adaptation to spatial and temporal diversity of marine resources within the archipelago. In: J. Denkinger and L. Vinueza (eds), <i>The Galapagos Marine Reserve</i>, pp. 61-70. Springer Verlag, New York.
- Cobb, K.M., Westphal, N., Sayani, H.R., Watson, J.T., Di Lorenzo, E., Cheng, H., Edwards, R.L. and Charles, C.D. 2013. Highly variable El Niño-Southern Oscillation throughout the Holocene. <i>Science </i> 339: 67-70.
- Villegas-Amtmann, S., Jeglinski, J.W.E., Costa, D.P., Robinson, P.W. and Trillmich, F. 2013. Individual foraging strategies reveal niche overlap between endangered Galapagos Pinnipeds. <i>PLOS ONE</i> 8(8): doi:101371/journal.pone.0070748.
- Jeglinski, J.W.E, Goetz, K.T., Werner, C., Costa, D.P. and Trillmich F. 2013. Same size – same niche? Foraging niche separation between sympatric juvenile Galapagos sea lions and adult Galapagos fur seals. <i>Journal of Animal Ecology</i> 82: 694-706.
- Brock, P.M., Hall, A.J., Goodman, S.J. and Acevedo-Whitehouse, K. 2013. Applying the tools of ecological immunology to conservation: a test case in the Galapagos sea lion. <i>Animal Conservation</i> 16: 19-31.
- Kraus, C., Mueller, B., Meise, K., Piedrahita, P., Pörschmann, U. and Trillmich, F. 2013. Mama’s boy: sex differences in juvenile survival in a highly dimorphic large mammal, the Galapagos sea lion. <i>Oecologia </i> 171: 893-903.
- Jeglinski, J.W.E., Werner, C., Robinson, P.W., Costa, D.P. and Trillmich, F. 2012. Age, body mass and environmental variation shape the foraging ontogeny of Galapagos sea lions. <i>Marine Ecology Progress Series</i> 453: 279-296.
- Villegas-Amtmann, S., Costa, D.P., Tremblay, Y., Salazar, S. and Aurioles-Gamboa, D. 2008. Multiple foraging strategies in a marine apex predator, the Galapagos Sea Lion <i>Zalophus wollebaeki</i>. <i>Marine Ecology Progress Series</i> 363: 299-309.
- Trillmich, F. and Wolf, J.B.W. 2008. Parent-offspring and sibling conflict in the Galápagos fur seals and sea lions. <i>Behavioral Ecology and Sociobiology</i> 62: 363-375.
- Wolf, J.B.W., Tautz, D. and Trillmich, F. 2007. Galapagos and Californian sea lions are separate species: genetic analysis of the genus <i>Zalophus</i> and its implications for conservation management. <i>Frontiers in Zoology</i> 4: doi:10.1186/1742-9994-4-20.
- Alava, J.J. and Salazar, S. 2006. Status and conservation of Otariids in Ecuador and the Galápagos Islands. In: A.W. Trites, S.K. Atkinson, D.P. DeMaster, L.W. Fritz, T.S. Gelatt, L.D. Rea and K.M. Wynne (eds), <i>Sea Lions of the World</i>, pp. 495-520. Fairbanks: Alaska Sea Grant College Program, Alaska, USA.
- Baillie, J.E.M., Hilton-Taylor, C. and Stuart, S.N. 2004. <i>2004 IUCN Red List of Threatened Species. A Global Species Assessment</i>. IUCN, Gland, Switzerland and Cambridge, UK.
- Gerber, L.R. and Hilborn, R. 2001. Catastrophic events and recovery from low densities in populations of otariids: implications for risk of extinction. <i>Mammal Review</i> 31(2): 131-150.
- Salazar, S. 2001. Auscultación y estudio de cadáveres de lobos marinos encontrados en “La Lobería” –Isla San Cristóbal. Informe Técnico. Estación Científica Charles Darwin. Departamento de Investigación y Conservación Marina. Santa Cruz, Galápagos, Ecuador.
- Dellinger, T. and Trillmich, F. 1999. Fish prey of the sympatric Galápagos fur seals and sea lions: seasonal variation and niche separation. <i>Canadian Journal of Zoology</i> 77: 1204-1216.
- Rice, D.W. 1998. <i>Marine Mammals of the World: Systematics and Distribution</i>. Society for Marine Mammalogy, Special Publication Number 4, Lawrence, Kansas.
- Trillmich, F. 1996. Parental investment in pinnipeds. <i>Advances in the Study of Behavior</i> 25: 533-577.
- Reijnders, P., Brasseur, S., van der Toorn, J., van der Wolf, P., Boyd, I., Harwood, J., Lavigne, D. and Lowry, L. 1993. <i>Seals, fur seals, sea lions, and walrus. Status survey and conservation action plan</i>. IUCN Seal Specialist Group.
- Trillmich, F. and Dellinger, T. 1991. The effects of El Niño on Galápagos pinnipeds. In: F. Trillmich and K.A. Ono (eds), <i>Pinnipeds and El Niño: Responses to environmental stress</i>, pp. 66-74. Springer-Verlag, Berlin, Germany.
- Trillmich, F. 1986. Attendance behavior of Galapagos sea lions. In: R. L. Gentry and G. L. Kooyman (eds), <i>Fur seals: Maternal strategies on land and at sea</i>, pp. 196-208. Princeton University Press, Princeton, NJ, USA.
- Trillmich, F. and Limberger, D. 1985. Drastic effects of El Niño on Galápagos pinnipeds. <i>Oecologia</i> 67: 19-22.
- Trillmich, F. and Trillmich, K.G.K. 1984. The mating systems of pinnipeds and marine iguanas: convergent evolution of polygyny. <i>Biological Journal of the Linnean Society</i> 21: 209-216.
- Trillmich, F. 1981. Mutual mother-pup recognition in Galápagos fur seals and sea lions: cues used and functional significance. <i>Behaviour </i> 78: 21-42.
- Trillmich, F. 1979. Noticias de Galapagos. <i>Noticias de Galapagos</i> 29: 8-14.
- Sivertsen, E. 1953. A new species of sea lion, <i>Zalophus wollebaeki</i>, from the Galapagos Islands. <i>Det Kongelige Norske Videnskabers Selskabs Forhandlinger</i> 26: 1-3.
Évaluateurs & contributeurs (3)Personnes ayant contribué à l'évaluation IUCNExpert
assessor
Trillmich, F.
evaluator
Aurioles-Gamboa, D.
facilitators
Lowry, L., Pollock, C.M., Ahonen, H., Chiozza, F. & Battistoni, A.
Trillmich, F. 2015. Zalophus wollebaeki. The IUCN Red List of Threatened Species 2015: e.T41668A45230540. Accessed on 05 May 2026.
Traits biologiques
20 valeurs · 5 sources
Morphologie(4)
Cycle de vie(1)
Voir 15 traits de plus (2 catégories)Replier
Reproduction(6)
Écologie & habitat(9)
Sources priorisées par qualité scientifique (peer-reviewed spécialisées → Wikidata fallback). Unités auto-converties, valeur max retenue en cas de mesures multiples. Méthodologie · Citations.
Répartition mondiale
Aucune observation géoréférencée avec précision suffisante (<10 km) dans GBIF pour cette espèce.
Consulter sur les bases externes
Observations & statuts
Cartographie
Note nomenclaturale & synonymesDétails taxonomiques + synonymes CoLExpert
Note nomenclaturale
TAXREF v18 — INPN/MNHNSynonymes (1)— redirigent vers cette page
- Zalophus californianus wollebaeki(Sivertsen, 1953)
Sources : Catalogue of Life Cross-References (synonymes) · TAXREF v18 INPN/MNHN (commentaires FR).