Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Squamata Iguanidae

Scientific Name: Amblyrhynchus cristatus ssp. cristatus
Species Authority: Bell, 1825
Parent Species:
Common Name(s):
English Galapagos Marine Iguana, Sea Iguana
French Amblyrhynche à crête, Iguane marin
Spanish Iguana Marina

Assessment Information [top]

Red List Category & Criteria: Vulnerable B2ac(iv) ver 3.1
Year Published: 2004
Date Assessed: 2004-04-30
Needs updating
Assessor(s): Nelson, K., Snell, H. & Wikelski, M.
Reviewer(s): Hudson, R. & Alberts, A. (Iguana Red List Authority)
The marine iguana Amblyrhynchus cristatus is endemic to the Galápagos Islands, Ecuador. A. c. cristatus is found on Fernandina Island. Extent of occurrence is estimated at less than 100 km² and area of occupancy at less than 10 km², both of which meet the CR criterion B thresholds. However, there is no continuing decline in habitat, range or population size and the population appears to be stable. The main threat to the population is future decline or loss through the effect of El Niño.

Geographic Range [top]

Range Description:A. c. cristatus occurs on Fernandina Island. Extent of occurrence is estimated at less than 1,000 km² and area of occupancy at less than 10 km².
Countries occurrence:
Ecuador (Galápagos)
FAO Marine Fishing Areas:
Pacific – southeast
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Average generation length is 5 years for females and 12 years for males. The total population is estimated at between 80,000–150,000 individuals and is stable.
Current Population Trend:Stable
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:The world's only marine lizard species. Adults and juveniles occur on rocky coast and intertidal zones. Adult females can be found nesting up to 2 km inland and adult males can be found in marine waters, up to depths of 20 m.
Systems:Terrestrial; Marine

Threats [top]

Major Threat(s): El Niño causes periodic dramatic (> 85%) mortality in A. cristatus. However, the A. c. cristatus population is apparently stable and the main threat is likely to be the subspecies’ restricted range area, which makes it vulnerable to stochastic events.

Conservation Actions [top]

Conservation Actions: A. cristatus is included on CITES Appendix II. It is under "Special Law" in the Galápagos and occurs in three protected areas: Galápagos National Park and National Marine Reserve; Galápagos Islands Man and Biosphere Reserve (UNESCO); and Galápagos Islands World Heritage Site.

Conservation actions recommended for the species include: further surveys for the subspecies, taxonomic research, and monitoring of the population.

Classifications [top]

9. Marine Neritic -> 9.1. Marine Neritic - Pelagic
suitability: Suitable  
10. Marine Oceanic -> 10.1. Marine Oceanic - Epipelagic (0-200m)
suitability: Suitable  
12. Marine Intertidal -> 12.1. Marine Intertidal - Rocky Shoreline
suitability: Suitable  
12. Marine Intertidal -> 12.4. Marine Intertidal - Mud Flats and Salt Flats
suitability: Suitable  

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Occur in at least one PA:Yes
In-Place Species Management
In-Place Education
8. Invasive & other problematic species & genes -> 8.1. Invasive non-native/alien species -> 8.1.1. Unspecified species
♦ timing: Future    
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

9. Pollution -> 9.2. Industrial & military effluents -> 9.2.1. Oil spills
♦ timing: Future    
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

11. Climate change & severe weather -> 11.4. Storms & flooding
♦ timing: Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

1. Research -> 1.1. Taxonomy
1. Research -> 1.2. Population size, distribution & trends
3. Monitoring -> 3.1. Population trends

Bibliography [top]

Carpenter, C. 1966. The marine iguana of the Galápagos Islands, its behavior and ecology. Proceedings of the California Academy of Sciences 34(6): 329-376.

IUCN. 1994. Iguanidae and Varanidae Conservation Assessment and Management Plan (CAMP) Taxon Reports. IUCN Conservation Breeding Specialist Group.

IUCN. 2004. 2004 IUCN Red List of Threatened Species. Downloaded on 23 November 2004.

Kruuk, H. and Snell, H. 1981. Prey selection by feral dogs from a population of marine iguanas (Amblyrhynchus cristatus). Journal of Applied Ecology 18: 197-204.

Laurie, A. 1981. Marine iguana census. Unpublished document.

Laurie, A. 1983. Marine iguanas in the Galápagos. Oryx 17: 18-25.

Laurie, A. 1987. Marine iguana project to continue. Noticas de Galápagos 45: 19-22.

Laurie, A. and Brown, D. 1990a. Population biology of marine iguanas (Amblyrhynchus cristatus). I. Changes infecundity related to a population crash. Journal of Animal Ecology. 59: 515-528.

Laurie, A. and Brown, D. 1990b. Changes in annual survival rates and the effects of size, sex, age and fecundity in a population crash. Journal of Animal Ecology 59: 529-544.

Laurie, A. and Brown, D. 1990c. Population biology of marine iguanas (Amblyrhynchus cristatus). III. Factors affecting survival. Journal of Animal Ecology. 59: 545-568.

Merlen, G. 1984. The 1982-83 El Niño: Some of its consequences for Galápagos wildlife. Noticas de Galápagos 41: 8-15.

Rassmann, K., Tautz, D., Trillmich, F. and Gliddon, C. 1997. The microevolution of the Galápagos marine iguana Amblyrhynchus cristatus assessed by nuclear and mitochondrial genetic analyses. Molecular Ecology 6: 437-452.

Trillmich, K. 1983. The mating system of the Marine Iguana (Amblyrhynchus cristatus). Z. Tierpsychology 63: 141-172.

Wikelski, M. and Trillmich, F. 1997. Body size and sexual size dimorphism in marine iguanas fluctuate as a result of opposing natural and sexual selection: an island comparison. Evolution 51(3): 922-936.

Wikelski, M., Carborne, C. and Trillmich, F. 1996. Lekking in marine iguanas: female grouping and male reproductive strategies. Animal Behaviour 52: 581-596.

Citation: Nelson, K., Snell, H. & Wikelski, M. 2004. Amblyrhynchus cristatus ssp. cristatus. In: The IUCN Red List of Threatened Species 2004: e.T44174A10868010. . Downloaded on 07 October 2015.
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