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Carcharhinus galapagensis

(Grey Reef Whaler)

Overview

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Family : Requiem sharks ; A common but habitat-limited tropical shark found close inshore to well as offshore near or on insular or continental shelves (Ref. 244). Prefers clear water with coral and rocky bottoms (Ref. 244). Although a coastal pelagic species, it is capable of crossing considerable distances of open ocean between islands (at least 50 km ) (Ref. 244). Juveniles restricted to shallower water, in 25 m or less (Ref. 244; 37816). Found in superficial aggregations (Ref. 244). Tends to feed near the bottom but may take bait from the surface (Ref. 5485). Feeds mainly on bottom fishes, also squid and octopi (Ref. 244). In the Galapagos Is. it preys on sea lions and marine iguanas (Ref. 28023). Aggressive and dangerous to people (Ref. 9997). Viviparous (Ref. 50449). 6 to 16 young of 57 to 80 cm are born per litter (Ref. 1602).

Threatened
Threat status

Common Names

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Click on the language to view common names.

Common Names in Afrikaans:

Galapagoshaai

Common Names in Dutch:

Galapagoshaai

Common Names in English:

Galapagos Shark, Grey Reef Whaler, Mackeral Shark, Mackerel Shark, Tollo

Common Names in French:

Requin Citron, Requin De Galapagos, Requin Demoiselle, Requin Des Galapagos

Common Names in Hawaiian:

Manô, Mano

Common Names in Japanese:

Garapagosu Zame

Common Names in Malay:

Yu

Common Names in Mandarin Chinese:

直翅真鯊, 直翅真鯊, 直翅真鲨

Common Names in Portuguese:

Cação, Cação, Tubarão-Dos-Galápagos, Tubarão-Dos-Galápagos

Common Names in Rapa:

Ma`o

Common Names in Rapanui:

Ma`o

Common Names in Samoan:

Malie

Common Names in Spanish:

Cazón, Cazón, Jaqueta, Jaquetón, Jaquetón, Tiburón, Tiburón De Galapagos, Tiburón De Galápagos, Tiburón, Tiburón De Arrecife, Tiburón De Galápagos, Tollo, Tollo-Cazón, Tollo-Cazón

Common Names in Thai:

Chalarm Thao

Description

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Family Carcharhinidae

Distribution: global. Gill openings 5, the fifth behind origin of pectoral fin. Small to large sharks with round eyes, internal nictitating eyelids , no nasoral grooves or barbels , usually no spiracles. Teeth usually bladelike with one cusp . Development usually viviparous with young born fully developed. Includes several dangerous species, but most prefer to avoid divers .The family Carcharhinidae belongs to the Class Elasmobranchii (sharks and rays ) and the Order Carcharhiniformes. It contains 12 genera and 50 species. It may be found in Marine , Brackish , and Freshwater environments and is primarily Marine. Members of this family are not used in the aquarium trade. Reproductively, most members of this family are bearers. The main mode of swimming of adult fish in this family is carangiform . Compared with other fish, the activity level of this family tends to be active . Members of this family have been dated back to the lower Eocene epoch of the Tertiary period. This family may be found from 41° n to 35° s and 115° w to 168° e. Etymology of this family name : Greek, karcharos, -ou = cutting, sharp and also a kind of shark + Greek, rhinos = nose

Physical Description

Species Carcharhinus galapagensis

Distinctive Features: This is a large shark with a slender, fusiform body and low inter-dorsal ridge between the first and second dorsal fins. The tall and nearly straight first dorsal fin originates over the posterior third of the pectoral fin inner margin . The long pelvic fins are straight, each with a pointed tip . The snout of the Galapagos shark is broadly rounded .

Resembling the grey reef shark (C. amblyrhyncos), the Galapagos shark can be distinguished with a more slender body and a slightly rounded tip on the first dorsal fin. The Galapagos shark very closely resembles the dusky shark (C. obscurus). The Galapagos shark has a much more erect first dorsal fin and larger teeth than the dusky shark, however this can be difficult without direct comparison of two specimens. The easiest method to distinguish these two species is by the number of precaudal vertebrae - there are 103-109 in the Galapagos shark and 86-97 in the dusky shark. To determine the number of vertebrae , the backbone must be exposed from the back of the skull to the base of the tail.

Coloration : The Galapagos shark is brownish-gray upper body and white ventral surface with or without dusky markings on the fins . An inconspicuous white band can sometimes be seen on the flanks.

Dentition: The serrated upper teeth are relatively long and broadly triangular in shape . The very finely serrated lower teeth are symmetrical and erect. Typically there are 14 teeth on either side of the symphysis in each jaw with one tooth located at the symphysis

Size, Age, and Growth: The Galapagos shark reaches a maximum length of 12.1 feet (3.7 m ). Male individuals mature at lengths of 6.9-7.5 feet (2.1-2.3 m) while females mature at 7.2-8.2 feet (2.2-2.5 m) in length. Age of Galapagos sharks at first reproductive effort is approximately 10 years. Maximum known lifespan is approximately 24 years.Males are commonly 300 cm (Total Length) in length when caught/marketed, but may be as large as 370 cm (Total Length).

Habitat

This shark is quite abundant in waters around oceanic islands , found close inshore as well as occasionally reported offshore in waters over continental and insular shelves to depths of 591 feet (180 m ). It has a preference for clear tropical waters with strong currents over coral or rocky bottom habitats . Although it is considered a coastal species, the Galapagos shark has been reported to cross open waters between islands. Juveniles are limited to waters shallower than 82 feet (25 m), which act as nursery grounds and help avoid cannibalism by their own parents. This shark often swims just above the bottom substrate, forming loose aggregations. May be found at depths of 0 to 180 meters. Usually found at depths of 30 to 180 meters.

Biome: Saltwater . Reef-associated .

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.


List of Habitats:9.1Marine Neritic - Pelagic 10.1Marine Oceanic - Epipelagic (0-200m)

Biology

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Diet

Feeds primarily on bottom-dwelling fishes as well as on squid and octopus . These fish include eels, flatheads , groupers, flatfish , and triggerfish. As Galapagos sharks reach large sizes, they also feed on other elasmobranchs . In the Galapagos Islands off the coast of Ecuador, it has been observed preying on sea lions and marine iguanas. The Galapagos shark displays threat gestures to warn competitors in the search for food.

Reproduction

Galapagos sharks are "viviparous", or livebearing, with embryos nourished by a yolksac-placenta during gestation . Mating and birth occurs early in the year within Hawaiian waters. Female individuals often have mating scars from males biting the gills , fins , and body. After gestation during which the embryos develop inside the mother, live birth results in a litter size of 4-16 pups . Each pup measures 24-31 inches (60-80 cm) in length. The pups stay in shallow water nursery areas to avoid predation and cannibalism from members of their own species, eventually moving out to deeper waters as they mature .

Behavior

Predators : Large sharks are potential predators of the Galapagos shark . Cannibalism is also reported within this species.

Taxonomy

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Ambiguous Synonyms

  1. Carcharias obscurus (non Lesueur)
  2. Eulamia obscurus (non Lesueur)

Unambiguous Synonyms

  1. Carcharhinus galapagensis (Snodgrass and Heller, 1905)
  2. Carcharhinus galapagensis (non Snodgrass & Heller, 1905)
  3. Carcharhinus galapaguensis
  4. Carcharhinus galapaguensis (Snodgras & Heller 1905)
  5. Carcharias galapagensis Snodgrass & Heller, 1905
  6. Carcharinus galapagensis (Snodgrass & Heller, 1905)

Notes

Name Status: Accepted Name . Latest taxonomic scrutiny: Group expert : Compagno L.J.V., Data last modified by FishBase 28-Oct-2000

Similar Species

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Members of the genus Carcharhinus

There are approximately 51 species in this genus:

C. acronotus (Blacknose Shark) · C. albimarginatus (Shark) · C. altima · C. altimus (Bignose Shark) · C. amblyrhynchoides (Graceful Shark) · C. amblyrhynchos (Black-Vee Whaler) · C. amboinensis (Ambon Sharpnose Puffer) · C. borneensis (Borneo Shark) · C. brachyurus (Bronze) · C. brevipinna (Blacktipped Shark) · C. cautus (Nervous Shark) · C. commersoni · C. commersonii · C. dussumieri (Blacktip Shark) · C. egertoni · C. elongatus · C. falciformis (Blackspot Shark) · C. fitzroyensis (Creek Whaler) · C. frequens · C. galapagensis (Galapagos Shark) · C. glauca · C. glaucus · C. hemiodon (Long Nosed Shark) · C. isodon (Eventooth Shark) · C. lamia · C. obscurus · C. leiodon (Smooth Tooth Blacktip Shark) · C. leucas (Bull Shark) · C. limbatus (Animals) · C. longimanus (Brown Milbert's Sand Bar Shark) · C. macloti (Hardnose Shark) · C. macrurus · C. longimanus · C. melanoptera · C. melanopterus (Black Fin Reef Shark) · C. sealei · C. obscurus (Bay Shark) · C. obtusus · C. perezi · C. perezii (Caribbean Reef Shark) · C. plumbeus · C. plumbeus (Brown Shark) · C. porosus (Shark) · C. priscus · C. sealei (Black-Spot Shark) · C. signatus (Night Shark) · C. sorrah (Black-Tip Shark) · C. amblyrhynchos · C. tilstoni (Australian Blacktip Shark) · C. sealei · C. limbatus

Bibliography

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More Info

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal March 01, 2008:

Identifiers

Last Revised: 2008-11-02