|Scientific Name:||Carcharhinus galapagensis|
|Species Authority:||(Snodgrass & Heller, 1905)|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|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)|
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.
|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 Stevens 1994, Schwartz 1998).|
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
|Range Map:||Click here to open the map viewer and explore range.|
|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:||
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.
|Major Threat(s):||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. 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)|
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).
|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 . Downloaded on 07 October 2015.|
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