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Galapagos Sea Lion Zalophus wollebaeki
The Galapagos sea lion occurs on all large and small islands
and rocks in the Galapagos Islands, and occasionally on Isla
de la Plata near mainland Ecuador ( IUCN
).
Vagrant animals have been seen along the Ecuadorian coast
north to Isla Gorgona, Colombia. The Galapagos sea lion was
considered a subspecies of the California sea lion. Recent
evidence is in favor of a full species (Rice 1998, Wolf et
al. 2007, Dasmahapatra et al. 2009).
Galapagos Sea Lion Breeding Behaviour
Galapagos sea lions breed from May to January (Wilson and Ruff
1999). After about a week, the pups go to sea with their
mothers to catch fish and periodically coming ashore to nurse.
Pups are weaned after about a year but some continue to nurse
up to two years (Wilson and Ruff 1999). Females enter estrous
a few weeks after giving birth and prepare to mate. Adult
females and pups are very tame toward humans often ignoring
their presence.
Galapagos Sea Lion Feeding Behaviour
In the Galapagos, sea lions eat fish in surface and coastal
upwelling water (mostly sardines
Dellinger and Trillmich 1999),
but will also feed in deep water, and in water over muddy and
sandy bottoms along the continental shelf or both in shallow
and deep waters between rocks (Villegas-Amtmann et al. 2008).
Galapagos
Sea Lion Conservation
There are about 30,000 Galapagos sea lions (Reeves et al.
2002). It was assessed as endangered by the
IUCN
in 2008 because of an apparent population decline. Galapagos
sea lions undergo natural population crashes during strong El
Nino events (Trillmich
and Limberger 1985).
The
Charles Darwin
Research Foundation
mission
is “to provide knowledge and assistance through scientific
research and complementary action to ensure the conservation
of the environment and biodiversity in the Galapagos
Archipelago.”
References
Dasmahapatra, KK, J I Hoffman and W Amos. 2009. Pinniped
phylogenetic relationships inferred using AFLP markers.
Heredity 103: 168–177.
Dellinger, T. and F. Trillmich 1999. Fish prey of the
sympatric Galápagos fur seals and sea lions: seasonal
variation and niche separation. Canadian Journal of Zoology
77: 1204-1216
Rice DW 1998. Marine Mammals of the World: Systematics and
Distribution. Society for Marine Mammalogy, Lawrence, KS.
Trillmich, F. and Limberger, D. 1985. Drastic effects of El
Niño on Galapagos pinnipeds. Oecologia 67: 19-22.
Wilson, D. and S. Ruff. 1999. Smithsonian book of North
American mammals. UBC Press, Vancouver.
Wolf, JBW, D. Tautz and F. Trillmich. 2007. Galápagos and
Californian sea lions are separate species: Genetic analysis
of the genus Zalophus and its implications for
conservation management. Frontiers in Zoology 4:20
Villegas-Amtmann, S., DP Costa, Y Tremblay, S Salazar, and D
Aurioles-Gamboa. 2008. Multiple foraging strategies in a
marine apex predator, the Galapagos sea lion Zalophus
wollebaeki. Marine Ecology Series 363: 299–309.
January 2012
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