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IUCN 2008: T41668A45230540
Zalophus wollebaeki, Galápagos Sea Lion
Assessment by: Trillmich, F.
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Citation: Trillmich, F. 2015. Zalophus wollebaeki. The IUCN Red List of Threatened Species 2015:
e.T41668A45230540. http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
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THE IUCN RED LIST OF THREATENED SPECIES™
Taxonomy
Kingdom
Phylum
Class
Order
Family
Animalia
Chordata
Mammalia
Carnivora
Otariidae
Taxon Name: Zalophus wollebaeki Sivertsen, 1953
Synonym(s):
• Zalophus californianus subspecies wollebaeki (Sivertsen, 1953)
Common Name(s):
• English:
• Spanish:
Galápagos Sea Lion
Leon Marino de Galápagos, Lobo de un Pelo de Galápagos, Lobo Marino de Galápagos
Taxonomic Notes:
The species has been considered a subspecies of Z. californianus (Z. c. wollebaeki) by many authors. Rice
(1998) argued for the retention of Z. californianus, Z. japonicus, and Z. wollebaeki as distinct species.
Recent genetic data support the classification as a separate species that separated from the California
Sea Lion (Zalophus californianus) about 2.3 ± 0.5 million years ago (Wolf et al. 2007).
Assessment Information
Red List Category & Criteria:
Endangered A2ab ver 3.1
Year Published:
2015
Date Assessed:
October 26, 2014
Justification:
The Galápagos Sea Lion population declined by 60-65% from 1978 to 2001. Since then there is no
evidence of further decline or increase; therefore it is likely that the population has still undergone a
reduction of more than 50% over the last three generations (1984-2014). The causes of the reduction
are partly understood, have not ceased, and may not be reversible. Impacts from El Niño events and
infectious diseases continue to threaten the population. Galápagos Sea Lions qualify for listing as EN
under criterion A2ab. However, the lack of quantitative survey information for the past 13 years greatly
increases the uncertainty of this assessment.
Previously Published Red List Assessments
2008 – Endangered (EN)
1996 – Vulnerable (VU)
1996 – Vulnerable (VU)
Geographic Range
Range Description:
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
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Galápagos Sea Lions are found throughout the Galápagos Archipelago on all the major islands and on
many smaller islands and rocks. A colony was established in 1986 at Isla de la Plata (coast of mainland
Ecuador, 1°17' S, 81°04' W), just offshore from mainland Ecuador, but this site is not regularly used.
Vagrants can be seen from the Ecuadorian coast north to Isla Gorgona in Colombia. There is also a
record from Isla del Coco, Costa Rica, approximately 500 km southwest of Costa Rica. This record lacks
genetic substantiation, so it cannot be decided whether the individual belonged to the Galápagos or the
California species of Sea Lion.
Country Occurrence:
Native: Ecuador (Ecuador (mainland), Galápagos)
Vagrant: Colombia; Costa Rica (Cocos I.)
FAO Marine Fishing Areas:
Native: Pacific - southeast
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
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Distribution Map
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
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Population
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.
Current Population Trend: Decreasing
Habitat and Ecology (see Appendix for additional information)
Galápagos Sea Lions are very similar in appearance to California Sea Lions (Zalophus californianus), but
are smaller and differ slightly in behaviour and skull morphology. Galápagos Sea Lions are sexually
dimorphic, with males larger than females and having a suite of secondary sexual characteristics. The
degree of sexual dimorphism appears to be less than in California Sea Lions, although few weights and
measurements are available for adults to confirm this suggestion. Adult males are estimated to weigh
up to 200 kg, but direct measurements outside the reproductive period showed a maximum of 158 kg
(Trillmich et al. 2014). Adult females caring for pups weigh between 50 and 95 kg (mean 60 kg, Trillmich
et al. 2014). Pups of both sexes are born already size dimorphic. Male newborns weigh on average 6.7
kg, females 5.8 kg (Kraus et al. 2013). Young are weaned when 1-3 years old at approximately 25-45 kg.
Pups are born with a brownish-black lanugo coat that fades to pale brown by three to five months. Pups
go through their first moult at around five to six months of age and emerge with the pelage of adult
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
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females and juveniles.
Female age at first birth is around six years (Trillmich et al. unpubl. data) and males are believed to
mature sexually at about the same age, although male social maturity is attained at older age. Females
produce one pup after a gestation of about 11 months, but may fail to become pregnant or abort if they
are still caring for an older offspring (Trillmich and Wolf 2008). Longevity is estimated to be 15-24 years
but the higher ages are not confirmed (Reijnders et al. 1993).
Galápagos Sea Lions are polygynous and males hold territories mostly along the shoreline in shallow
water that they vociferously and aggressively defend. Male tenure on territories usually lasts from a few
days to one month. Males may be more than once on territory during the drawn out reproductive
period. Most copulations occur in the water.
Pupping and breeding take place across an extended period from May through February. The timing
varies among islands within the archipelago. Because of the protracted breeding season and extended
care provided to offspring (up to three years) by females, there are dependent offspring on the
rookeries year-round. Females may wean offspring in 11-12 months in productive years or areas, but
most continue to suckle yearlings for a second year. Some females care for a yearling along with a
newborn pup. Pups are attended continuously for the first 4-7 days after birth, after which the female
goes to sea to feed. With the departure, the female begins a cycle of foraging trips that last 0.5-3 days
during the cold season, but may last considerably longer in the warm season. Pups will enter the water
and begin to develop swimming skills 1-2 weeks after birth. In some colonies, females return at night to
nurse their pup, departing again the next morning (Trillmich 1986). Females and pups recognize each
other and reunite based on calls and scent (Trillmich 1981). Galápagos Sea Lion females feed during day
and night, in contrast to Galápagos Fur Seals, which primarily feed at night (Jeglinski et al. 2013; VillegasAmtmann et al. 2008, 2013).
Galápagos Sea Lions are non-migratory. They are rather unafraid of humans when ashore, at least in the
sites where they regularly encounter humans. Haul-out sites can be on rugged shoreline types, including
steep rocky shorelines, ledges and offshore stacks, but colonies are mostly on gently sloping sandy and
rocky beaches. Sea lions will use shade from vegetation, rocks, and cliffs, and enter tidal and drainage
pools or move into the ocean, as needed during the heat of the day to avoid overheating.
Diving has been studied on Fernandina, Floreana, Caamaño and San Cristóbal. The maximum dive depth
recorded for an adult female was 584 m and mean maximal duration was 9.8 minutes (Jeglinski et al.
2013). Average depth of dives varied between 45 and 94 m and dives lasted for 3-5 minutes (VillegasAmtmann et al. 2008, Jeglinski et al. 2012, 2013). Galápagos Sea Lion females mostly use shelf areas for
foraging. When resting at sea they will raft at the surface with one or more flippers held vertically in the
air.
Galápagos Sea Lions prey on sardines (Dellinger and Trillmich 1999) as well as myctophids and
bathylagids together with small squid. Diet breadth apparently varies across years and perhaps also
seasonally and appears to be influenced by El Niño events (Paez-Rosas et al. 2014). During El Niño
events prey includes green-eyes and myctophids, suggesting a change in foraging strategy.
Feral and uncontrolled dogs have been reported to kill Sea Lion pups and bite juveniles and adults. Shark
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
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predation is evident from animals seen with injuries and scars from attacks, and killer whales are
presumed to be another predator on Galápagos Sea Lions. Interestingly, juvenile and adult Galápagos
Sea Lions have been observed to mob Galápagos sharks that approach colonies, and also at haul out
sites and resting places in shallow bays (Trillmich 1996).
Systems: Terrestrial, Marine
Use and Trade
The Galápagos Sea Lion population lives in the Galápagos Archipelago, which is an Ecuadorian National
Park surrounded by a marine resources reserve. There is no use or trade of this species.
Threats (see Appendix for additional information)
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.
Conservation Actions (see Appendix for additional information)
The Galápagos Sea Lion population lives in the Galápagos Archipelago, which is an Ecuadorian National
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
6
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.
Credits
Assessor(s):
Trillmich, F.
Reviewer(s):
Aurioles-Gamboa, D.
Facilitators(s) and
Compiler(s):
Lowry, L., Pollock, C.M., Ahonen, H., Chiozza, F. & Battistoni, A.
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
7
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Species Assessment. IUCN, Gland, Switzerland and Cambridge, UK.
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. Animal Conservation 16: 19-31.
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
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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. Science 339: 67-70.
Dellinger, T. and Trillmich, F. 1999. Fish prey of the sympatric Galápagos fur seals and sea lions: seasonal
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Gerber, L.R. and Hilborn, R. 2001. Catastrophic events and recovery from low densities in populations of
otariids: implications for risk of extinction. Mammal Review 31(2): 131-150.
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(Accessed: 23 June 2015).
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seals. Journal of Animal Ecology 82: 694-706.
Jeglinski, J.W.E., Werner, C., Robinson, P.W., Costa, D.P. and Trillmich, F. 2012. Age, body mass and
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Series 453: 279-296.
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. Oecologia
171: 893-903.
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The Galapagos Marine Reserve, pp. 71-80. Springer Verlag, New York.
Reijnders, P., Brasseur, S., van der Toorn, J., van der Wolf, P., Boyd, I., Harwood, J., Lavigne, D. and Lowry,
L. 1993. Seals, fur seals, sea lions, and walrus. Status survey and conservation action plan. IUCN Seal
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Rice, D.W. 1998. Marine Mammals of the World: Systematics and Distribution. Society for Marine
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–Isla San Cristóbal. Informe Técnico. Estación Científica Charles Darwin. Departamento de Investigación
y Conservación Marina. Santa Cruz, Galápagos, Ecuador.
Sivertsen, E. 1953. A new species of sea lion, Zalophus wollebaeki, from the Galapagos Islands. Det
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Kongelige Norske Videnskabers Selskabs Forhandlinger 26: 1-3.
Trillmich, F. 1979. Noticias de Galapagos. Noticias de Galapagos 29: 8-14.
Trillmich, F. 1981. Mutual mother-pup recognition in Galápagos fur seals and sea lions: cues used and
functional significance. Behaviour 78: 21-42.
Trillmich, F. 1986. Attendance behavior of Galapagos sea lions. In: R. L. Gentry and G. L. Kooyman (eds),
Fur seals: Maternal strategies on land and at sea, pp. 196-208. Princeton University Press, Princeton, NJ,
USA.
Trillmich, F. 1996. Parental investment in pinnipeds. Advances in the Study of Behavior 25: 533-577.
Trillmich, F. and Dellinger, T. 1991. The effects of El Niño on Galápagos pinnipeds. In: F. Trillmich and K.A.
Ono (eds), Pinnipeds and El Niño: Responses to environmental stress, pp. 66-74. Springer-Verlag, Berlin,
Germany.
Trillmich, F. and Limberger, D. 1985. Drastic effects of El Niño on Galápagos pinnipeds. Oecologia 67: 1922.
Trillmich, F. and Trillmich, K.G.K. 1984. The mating systems of pinnipeds and marine iguanas: convergent
evolution of polygyny. Biological Journal of the Linnean Society 21: 209-216.
Trillmich, F. and Wolf, J.B.W. 2008. Parent-offspring and sibling conflict in the Galápagos fur seals and sea
lions. Behavioral Ecology and Sociobiology 62: 363-375.
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), The Galapagos Marine Reserve, pp. 61-70. Springer Verlag, New York.
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 Zalophus wollebaeki. Marine
Ecology Progress Series 363: 299-309.
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. PLOS ONE 8(8):
doi:101371/journal.pone.0070748.
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Zoology 4: doi:10.1186/1742-9994-4-20.
Citation
Trillmich, F. 2015. Zalophus wollebaeki. The IUCN Red List of Threatened Species 2015:
e.T41668A45230540. http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
Disclaimer
To make use of this information, please check the Terms of Use.
External Resources
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9
Appendix
Habitats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Habitat
Season
Suitability
Major
Importance?
9. Marine Neritic -> 9.1. Marine Neritic - Pelagic
Resident
Suitable
Yes
10. Marine Oceanic -> 10.1. Marine Oceanic - Epipelagic (0-200m)
Resident
Suitable
Yes
10. Marine Oceanic -> 10.2. Marine Oceanic - Mesopelagic (200-1000m)
Resident
Suitable
No
12. Marine Intertidal -> 12.1. Marine Intertidal - Rocky Shoreline
Resident
Suitable
Yes
13. Marine Coastal/Supratidal -> 13.1. Marine Coastal/Supratidal - Sea Cliffs
and Rocky Offshore Islands
Resident
Suitable
Yes
Threats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Threat
Timing
Scope
Severity
Impact Score
8. Invasive & other problematic species & genes ->
8.1. Invasive non-native/alien species -> 8.1.1.
Unspecified species
Ongoing
Majority (5090%)
Causing/could
cause fluctuations
Medium
impact: 6
Stresses:
2. Species Stresses -> 2.1. Species mortality
2. Species Stresses -> 2.3. Indirect species effects ->
2.3.7. Reduced reproductive success
Ongoing
Minority (50%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
Minority (50%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
Majority (5090%)
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
Ongoing
Whole (>90%)
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
2. Species Stresses -> 2.1. Species mortality
2. Species Stresses -> 2.2. Species disturbance
2. Species Stresses -> 2.3. Indirect species effects ->
2.3.7. Reduced reproductive success
8. Invasive & other problematic species & genes ->
8.1. Invasive non-native/alien species -> 8.1.2.
Named species (Canis familiaris)
8. Invasive & other problematic species & genes ->
8.1. Invasive non-native/alien species -> 8.1.2.
Named species
9. Pollution -> 9.4. Garbage & solid waste
11. Climate change & severe weather -> 11.5. Other
impacts
Negligible declines
Negligible declines
Negligible declines
Rapid declines
Low impact: 4
Low impact: 4
Low impact: 5
High impact: 8
Conservation Actions in Place
(http://www.iucnredlist.org/technical-documents/classification-schemes)
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
10
Conservation Actions in Place
In-Place Research, Monitoring and Planning
Systematic monitoring scheme: No
In-Place Land/Water Protection and Management
Conservation sites identified: Yes, over entire range
Occur in at least one PA: Yes
Percentage of population protected by PAs (0-100): 91-100
Invasive species control or prevention: Yes
In-Place Species Management
Harvest management plan: No
Successfully reintroduced or introduced beningly: No
Subject to ex-situ conservation: No
In-Place Education
Subject to recent education and awareness programmes: Yes
Included in international legislation: No
Subject to any international management/trade controls: Yes
Conservation Actions Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Actions Needed
2. Land/water management -> 2.1. Site/area management
3. Species management -> 3.2. Species recovery
Research Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Research Needed
1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.5. Threats
1. Research -> 1.6. Actions
3. Monitoring -> 3.1. Population trends
Additional Data Fields
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
11
Distribution
Estimated area of occupancy (AOO) (km²): 106472
Continuing decline in area of occupancy (AOO): No
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) (km²): 325468
Continuing decline in extent of occurrence (EOO): No
Extreme fluctuations in extent of occurrence (EOO): No
Continuing decline in number of locations: No
Extreme fluctuations in the number of locations: No
Lower elevation limit (m): 0
Upper elevation limit (m): 5
Lower depth limit (m): 584
Upper depth limit (m): 0
Population
Number of mature individuals: 9200-10600
Continuing decline of mature individuals: Unknown
Extreme fluctuations: No
Population severely fragmented: No
Extreme fluctuations in subpopulations: No
All individuals in one subpopulation: Yes
Habitats and Ecology
Continuing decline in area, extent and/or quality of habitat: No
Generation Length (years): 10
Movement patterns: Not a Migrant
Congregatory: Congregatory (and dispersive)
© The IUCN Red List of Threatened Species: Zalophus wollebaeki – published in 2015.
http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T41668A45230540.en
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The IUCN Red List Partnership
The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species
Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership. The IUCN
Red List Partners are: BirdLife International; Botanic Gardens Conservation International; Conservation
International; Microsoft; NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas
A&M University; Wildscreen; and Zoological Society of London.
THE IUCN RED LIST OF THREATENED SPECIES™