Carcharhinus Galapagensis, Galapagos Shark

The IUCN Red List of Threatened Species™ ISSN 2307-8235 (online) IUCN 2008: T41736A10550977

Carcharhinus galapagensis, Galapagos Shark

Assessment by: Bennett, M.B., Gordon, I. & Kyne, P.M. ( SSG Australia & Oceania Regional Workshop, March 2003)

View on www.iucnredlist.org

Citation: Bennett, M.B., Gordon, I. & Kyne, P.M. ( SSG Australia & Oceania Regional Workshop, March 2003). 2003. Carcharhinus galapagensis. The IUCN Red List of Threatened Species 2003: e.T41736A10550977. http://dx.doi.org/10.2305/IUCN.UK.2003.RLTS.T41736A10550977.en

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THE IUCN RED LIST OF THREATENED SPECIES™ Taxonomy

Kingdom Phylum Class Order Family

Animalia Chordata Chondrichthyes Carcharhiniformes Carcharhinidae

Taxon Name: Carcharhinus galapagensis (Snodgrass & Heller, 1905)

Common Name(s): • English: Galapagos Shark Assessment Information

Red List Category & Criteria: Near Threatened ver 3.1

Year Published: 2003

Date Assessed: April 30, 2003

Annotations: Needs Updating

Justification: Carcharhinus galapagensis has a widespread, but patchy distribution, occurring at many widely separated island and some coastal sites in the Pacific, Atlantic and Indian Oceans.

It is classified globally as Near Threatened (just failing to meet Vulnerable A2acd, and likely to be A3d in the near future) because populations at many of these sites may be subject to high levels of fishing pressure (tuna longline fisheries, targeted drop-line fishing, recreational/tourism-based angling). There is considerable potential to cause severe local declines in the number of mature individuals. Evidence of such reductions/extirpations exists for this species around Central America (Pacific and Atlantic Oceans). As the species has a limited intrinsic rebound potential, and there are no data on recruitment to isolated sites, such local depletions could lead to loss of populations at specific localities. Continued fishing pressures throughout its range will result in further declines and populations require monitoring.

The species is classified as Data Deficient in Australia and Oceania: although it is not considered to be under threat off Lord Howe Island (Australia) and off the Kermadec Islands (New Zealand) where a marine reserve encompasses the species' range, there is currently no information on these populations. Geographic Range

Range Description: Circumglobal distribution in warm and temperate waters. Essentially limited to oceanic islands (e.g. Galapagos Is.; Clipperton Is.; Virgin Is.; St. Paul's Rocks; Azores; St. Helena; Ascension Is.; Ogasawara Is.; Lord Howe Is., Norfolk Is.; Kermadec Is., Rapa Is., Hawaiian Is.). Also from high seas and adjacent to continental shelves (e.g. California & N. Carolina, U.S.A.). Regionally, known from Lord Howe Island (Aust), American Samoa, Western Samoa, Cook Is., French Polynesia, and the Kermadec Islands (NZ). Records suggest that it may also occur along the continental shelves of adjacent landmasses (Last and

Country Occurrence: Native: American Samoa (American Samoa, American Samoa); Australia (Lord Howe Is.); Bermuda; Colombia; Cook Islands; Ecuador (Galápagos); French Polynesia; Japan (Ogasawara-shoto); Madagascar; New Zealand (Kermadec Is.); Norfolk Island; Panama; Portugal (Azores, Madeira); Saint Helena, Ascension and Tristan da Cunha (Ascension); Samoa; Sao Tomé and Principe; United States (California, Hawaiian Is.)

FAO Marine Fishing Areas: Present - origin uncertain: Atlantic - eastern central, Atlantic - northeast, Atlantic - northwest, Atlantic - southeast, Atlantic - western central, Indian Ocean - western, Pacific - eastern central, Pacific - southeast, Pacific - southwest, Pacific - western central

© The IUCN Red List of Threatened Species: Carcharhinus galapagensis – published in 2003. 3 http://dx.doi.org/10.2305/IUCN.UK.2003.RLTS.T41736A10550977.en Population Reported as a very common inshore species at oceanic islands off Central and South America (Beebe and Tee-Van 1941), but may have undergone severe population reductions at many of these islands. Very common species at Saint Paul's Rocks, a group of barren islets on the mid-Atlantic Ridge, where the shark population is reported to be "one of the densest shark populations of the Atlantic Ocean" (Edwards and Lubbock 1982). This species is reported to be one of the more common sharks in the main Hawaiian Islands and is very abundant at the Northwestern Hawaiian Islands (Wetherbee et al. 1996). This single study on the Hawaiian population suggests that the species is locally numerous and there is no immediate negative impact on the population by moderate fishing pressure (no measurable effect on CPUE over two seasons of long-lining). There are no data on the populations at other sites. Current Population Trend: Unknown

Habitat and Ecology (see Appendix for additional information) Carcharhinus galapagensis is most commonly found over rugged, rocky terrain in clear water. There is a suggestion that this species prefers areas with strong water currents. In Hawaii the majority of sharks were found near points of land characterised by having currents that converge and move offshore at those points (Wetherbee et al. 1996). Isolated rocky islets serve as congregation sites (Edwards and Lubbock 1982, Brum and Azevedo 1995), suggesting that underwater pinnacles may also be suitable habitat, giving this species a more extensive range of sites than currently understood. Occurs from surface waters to depths of over 280 m, with some suggestion of segregation on the basis of size. Vertical distribution patterns appear to be site specific and vary considerably between geographical areas/habitat types. In some regions juveniles are found in shallow water (less than 1 m) whereas in others they prefer deeper water (around 40 m) (Wetherbee et al. 1996). This species is reputed to reach a maximum body size of about 350 cm total length (TL), although specific records suggest that 300 cm TL appears more likely. Females mature at about 215 to 250 cm TL, males at about 205 to 250 cm TL (Bass et al. 1973, Last and Stevens 1994, Wetherbee et al. 1996). Estimated age at maturity is 6 to 8 years for males and 6.5 to 9 years for females (De Crosta et al. 1984). Litter size ranges from 4 to 16, with young born at 60 to 81 cm TL. Reproductive life histories are not well known. Females probably breed every two (or three) years with mating likely to occur in winter/spring. The species has a limited intrinsic rebound potential (Smith et al. 1998).

Carcharhinus galapagensis feeds primarily on demersal prey with fishes and cephalopods important to all size classes. Ontogenetic dietary shifts occur, with sharks and rays taken by larger (>200 cm TL) individuals. Ascribed a relatively high trophic level of 4.2 (Cortés 1999). An aggressive shark considered potentially dangerous to humans.

Systems: Marine

Threats (see Appendix for additional information) The life history parameters of this species make it susceptible to population declines from which it may not recover. The major threat comes from long-lining and other bait-fishing activities around islands and sub-sea mounts throughout its range. The aggressive nature of this common species together with the occupation of inshore habitats may result in pressures to extirpate local populations. Evidence of such reductions/extirpations exists for this species around Central America (Pacific and Atlantic Oceans) (L.J.V.

© The IUCN Red List of Threatened Species: Carcharhinus galapagensis – published in 2003. 4 http://dx.doi.org/10.2305/IUCN.UK.2003.RLTS.T41736A10550977.en Compagno, pers. comm.). The interrupted geographical distribution and unknown level of immigration to these isolated populations could place subpopulations at significant risk from over fishing. It should also be noted that uncontrolled legal and illegal shark fin fishing takes place at sites in the Pacific, including the Galápagos Marine Resources Reserve where a significant population of this species is known to occur (Bonfil et al. in press)

Conservation Actions (see Appendix for additional information) The Data Deficient listing for Australia and Oceania waters reflects the lack of information about this species in this region where it is the species is known from only a very few sites, and the number of individuals, their movements on a daily and seasonal basis and the levels of immigration/emigration are unknown. At these sites, a program that would encourage anglers to tag and release Galapagos sharks should help safeguard the populations and expand on our limited knowledge base. Involvement of tourist diving companies would assist in conservation efforts by raising public awareness and providing useful data on shark behaviour, numbers and preferred habitats.

The population at the Kermadec Islands is protected by a 12 nm marine reserve which extends in places to cover depths of over 3,000 m. The species also occurs within other marine reserves such as the Galápagos Marine Resources Reserve, (unfortunately illegal fishing is known to occur here). Credits

Assessor(s): Bennett, M.B., Gordon, I. & Kyne, P.M. ( SSG Australia & Oceania Regional Workshop, March 2003)

Reviewer(s): Fowler, S. & Cavanagh, R.D. (Shark Red List Authority)

© The IUCN Red List of Threatened Species: Carcharhinus galapagensis – published in 2003. 5 http://dx.doi.org/10.2305/IUCN.UK.2003.RLTS.T41736A10550977.en Bibliography Bass, A.J., D'Aubrey, J.D. and Kistnasamy, M. 1973. Sharks of the east coast of southern Africa. 1. The genus Carcharhinus (Carcharhinidae). Investigative Report of the Oceanographic Research Institute, Durban 33.

Beebe, W. and Tee-Van, J. 1941. Eastern Pacific expeditions of the New York Zoological Society. 25. Fishes from the tropical eastern Pacific. Part 2. Sharks. Zoologica 26: 93-122.

Bonfil, R., Simpfendorfer, C.A. and Acuña, E. 2005. Regional Overview: Southeast Pacific. In: S.L. Fowler, M. Camhi, G.H. Burgess, G.M. Cailliet, S.V. Fordham, R.D. Cavanagh, C.A. Simpfendorfer and J.A. Musick (eds). Sharks, rays and chimaeras: the status of the chondrichthyan fishes, pp. 186-193. IUCN SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Brum, J.M.M. and Azevedo, J.M.N. 1995. First record of the Galapagos shark Carcharhinus galapagensis (Snodgrass & Heller, 1905) (Carcharhinidae) on the Azores. Boletim do Museu Municipal do Funchal (História Natural) Sup. 4, 139-143.

Cortés, E. 1999. Standardized diet compositions and trophic levels of sharks. ICES Journal of Marine Science 56: 707-717.

De Crosta, M.A., Taylor Jr., L.R. and Parrish, J.D. 1984. Age determination, growth, and energetics of three species of carcharhinid sharks in Hawai'i. In: Proceedings of the Second Symposium on Resource Investigations of the Northwestern Hawaiian Islands Vol. 2. pp. 75-95. University of Hawai'i Sea Grant, UNIHI-SEAGRANT-MR-84-01.

Edwards, A.J. and Lubbock, H.R. 1982. The shark population of Saint Paul's Rocks. Copeia 1982: 223- 225.

IUCN. 2003. 2003 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 18 November 2003.

IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/.

Last, P.R. and Stevens, J.D. 2009. Sharks and Rays of Australia. Second Edition. CSIRO Publishing, Collingwood.

Schwartz, F.J. 1998. History of the Poor Boy Shark Tournament in North Carolina, 1982-1996. Journal of the Elisha Mitchell Scientific Society 114: 149-158.

Smith, S.E., Au, D.W. and Show, C. 1998. Intrinsic rebound potentials of 26 species of Pacific sharks. Marine and Freshwater Research 49(7): 663–678.

Wetherbee, B.M., Crow, G.L. and Lowe, C.G. 1996. Biology of the Galapagos shark, Carcharhinus galapagensis, in Hawai'i. Environmental Biology of Fishes 45: 299-310.

Citation Bennett, M.B., Gordon, I. & Kyne, P.M. ( SSG Australia & Oceania Regional Workshop, March 2003). 2003. Carcharhinus galapagensis. The IUCN Red List of Threatened Species 2003: e.T41736A10550977. http://dx.doi.org/10.2305/IUCN.UK.2003.RLTS.T41736A10550977.en

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© The IUCN Red List of Threatened Species: Carcharhinus galapagensis – published in 2003. 6 http://dx.doi.org/10.2305/IUCN.UK.2003.RLTS.T41736A10550977.en External Resources For Images and External Links to Additional Information, please see the Red List website.

Habitats (http://www.iucnredlist.org/technical-documents/classification-schemes)

Major Season Suitability Habitat Importance? 9. Marine Neritic -> 9.1. Marine Neritic - Pelagic - Unknown -

10. Marine Oceanic -> 10.1. Marine Oceanic - Epipelagic (0-200m) - Unknown -

Threats (http://www.iucnredlist.org/technical-documents/classification-schemes)

Threat Timing Scope Severity Impact Score 5. Biological resource use -> 5.4. Fishing & harvesting Ongoing - - - aquatic resources -> 5.4.3. Unintentional effects: (subsistence/small scale)

5. Biological resource use -> 5.4. Fishing & harvesting Ongoing - - - aquatic resources -> 5.4.4. Unintentional effects: (large scale)

Conservation Actions Needed (http://www.iucnredlist.org/technical-documents/classification-schemes)

Conservation Actions Needed 4. Education & awareness -> 4.3. Awareness & communications

Research Needed (http://www.iucnredlist.org/technical-documents/classification-schemes)

Research Needed 1. Research -> 1.2. Population size, distribution & trends

1. Research -> 1.3. Life history & ecology

3. Monitoring -> 3.1. Population trends

© The IUCN Red List of Threatened Species: Carcharhinus galapagensis – published in 2003. 8 http://dx.doi.org/10.2305/IUCN.UK.2003.RLTS.T41736A10550977.en The IUCN Red List of Threatened Species™ ISSN 2307-8235 (online) IUCN 2008: T41736A10550977

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