Grey Reef Shark
Carcharhinus amblyrhynchos
The grey reef shark gets its name from its grey colored dorsal side (back), which includes a bronze tint. It can be found in tropical ocean waters especially around coral reefs. Its diet includes squid, crustaceans, octopus, and various fishes. Female grey reef sharks give birth to live young (between one and six offspring each time). Grey reef sharks are slow swimmers and have a tendency of visiting the same site day after day.
Credit: Aquarium of the Pacific/Robin Riggs
SPECIES IN DETAIL
Grey Reef Shark
Carcharhinus amblyrhynchos
CONSERVATION STATUS: Endangered
CLIMATE CHANGE: Uncertain
At the Aquarium
The Aquarium has one grey reef shark in Shark Lagoon.
Geographic Distribution
The grey reef shark has a widespread distribution, ranging from the Indo-West Pacific to the Central Pacific, Madagascar, the tropical Mauritius-Seychelles area in the Indian Ocean to the Tuamoto archipelago in the Southern Pacific ocean, and Northern Australia to Southern China.
Habitat
The grey reef shark lives in tropical open ocean waters from the surface to depths of around 280 meters (918.6 feet). It can also be found around coral reefs, specifically near drop-offs (the point where the beach ends and the ocean begins) and the edges of coral reefs. Within their habitat, they have a tendency of returning to the same site day after day (fidelity).
Physical Characteristics
This shark possesses classic shark traits: fusiform shape (tapers at both ends, resembling a football); anal fin (fin located on the underside of the fish, right before the caudal or tail fin); and five gill slits. It also has a long, rounded snout. Its mouth is underneath the snout, just behind its round eyes. Its dorsal fin (the fin located on a fish’s dorsal or back side) can be either grey or white-tipped. The shark’s ventral side (underside) ranges from a pale color to white. Additionally, it has a thick black band on the edge of its caudal fin (tail fin) and black markings on the tips of its pectoral fins (side fins).
Males are larger than females and possess elongated claspers behind their pelvic fins (fins located on the fish’s underside before the anal fins) that are utilized during mating.
Like all shark species, the grey reef shark has a cartilaginous skeleton (a skeleton composed of cartilage rather than bone tissue). Unlike a rigid bony skeleton, the structure of the grey reef shark (and of all sharks and rays in general) is flexible and maneuverable thanks to the cartilage in it, allowing the shark to bend its body and move in ways it wouldn’t be able had it possessed a bony skeleton. This cartilage allows the shark to evade predators and find prey much more easily. Also, like all sharks, the grey reef shark has a mouth with rows of teeth which are serrated and triangular. Sharks (and rays) replace their teeth like a conveyer belt: as the teeth in the front row fall out, the teeth behind them move forward to take their place.
Size
The maximum length for males is 2.6 meters (8.4 feet) and for females is 1.7 meters (5.6 feet). Their weight ranges from 20—30 kilograms (44—66 pounds).
Diet
Their diet consists of fishes, crustaceans (crab, lobsters, and shrimp), and cephalopods (squid and octopus).
Reproduction
This species of shark gives birth to live young and reproduces by internal fertilization. When the female is ready to mate (age of maturity is between seven and eight years old), she releases chemical substances called pheromones into the water. Both the male and female give behavioral cues that involve the male performing a dance and the female swimming away until the male lunges at the female and seizes her with his teeth before they mate. Fortunately, females have thicker skin on their backs, possibly for this exact reason.
Male sharks use claspers (reproductive structures located between their pelvic fins) to direct sperm into the female. The sperm can fertilize the egg at the time of mating or can be stored until an egg is released. Gestation (development) lasts twelve months. Female grey reef sharks produce one to six offspring each time.
Behavior
During the day, grey reef sharks will form aggregations or schools. However, these sharks are more active at night. They are slow swimmers and may be territorial. They have a distinct agonistic display (a behavior related to fighting) in which they arch their backs, point their pectoral fins (side fins) downward, and swing their heads sideways in a slow motion as they swim. Grey reef sharks are known to be curious and often approach divers.
Adaptation
Like all elasmobranchs (sharks and rays), grey reef sharks exhibit a form of camouflage known as countershading, in which their dorsal side (back side) is darker than their ventral side (underside). Countershading helps the shark appear less visible to both predators and prey from above and below, allowing them to find prey and evade predators more easily. Additionally, this species has excellent senses, especially its sense of smell. They use a system of organs that run along their sides called the lateral line to detect movement and pressure changes in the water around them. They also use tiny gel-filled pores around their snouts called ampullae of Lorenzini to detect electromagnetic signals to navigate and find prey.
Longevity
The lifespan for this species is estimated to be about twenty-five years.
Conservation
According to the International Union for Conservation of Nature (IUCN), the grey reef shark is considered Endangered because of its habitat choice, coastal distribution, high fidelity (faithfulness) to a particular site, small litter size, and slow maturity rate. It is subject to overfishing as they are used for a wide variety of human consumption, from shark fin soup to fishmeal to other shark-filled products. Because this shark species matures at a slow rate, they are unable to reproduce fast enough to combat overfishing.
The grey reef shark’s coral reef habitat is also affected by global climate change and destructive fishing practices such as dynamite fishing (fishing that utilizes explosives, resulting in a larger catch) and declining water quality.
Fortunately, conservation efforts are being made for the grey reef shark (and all sharks in general). One way is by utilizing marine protected areas or MPAs, parts of the ocean that the government has set aside for marine life and that limit human activity. Another way is by managing commercial and recreational shark fisheries and working with fishery management councils to conserve and manage sharks in a sustainable way. Restrictions on shark harvests are also being implemented. Educating the public about how human practices like overfishing, shark consumption, and dynamite fishing habitat affects sharks and their habitat is yet another way we can help save sharks.
Special Notes
When hunting for prey, grey reef sharks can reach speeds of up to 40.2 km/hr (25 mph).
A typical shark may lose up to 30,000 teeth in its lifetime.
SPECIES IN DETAIL | Print full entry
Grey Reef Shark
Carcharhinus amblyrhynchos
CONSERVATION STATUS: Endangered
CLIMATE CHANGE: Uncertain
The Aquarium has one grey reef shark in Shark Lagoon.
The grey reef shark has a widespread distribution, ranging from the Indo-West Pacific to the Central Pacific, Madagascar, the tropical Mauritius-Seychelles area in the Indian Ocean to the Tuamoto archipelago in the Southern Pacific ocean, and Northern Australia to Southern China.
The grey reef shark lives in tropical open ocean waters from the surface to depths of around 280 meters (918.6 feet). It can also be found around coral reefs, specifically near drop-offs (the point where the beach ends and the ocean begins) and the edges of coral reefs. Within their habitat, they have a tendency of returning to the same site day after day (fidelity).
This shark possesses classic shark traits: fusiform shape (tapers at both ends, resembling a football); anal fin (fin located on the underside of the fish, right before the caudal or tail fin); and five gill slits. It also has a long, rounded snout. Its mouth is underneath the snout, just behind its round eyes. Its dorsal fin (the fin located on a fish’s dorsal or back side) can be either grey or white-tipped. The shark’s ventral side (underside) ranges from a pale color to white. Additionally, it has a thick black band on the edge of its caudal fin (tail fin) and black markings on the tips of its pectoral fins (side fins).
Males are larger than females and possess elongated claspers behind their pelvic fins (fins located on the fish’s underside before the anal fins) that are utilized during mating.
Like all shark species, the grey reef shark has a cartilaginous skeleton (a skeleton composed of cartilage rather than bone tissue). Unlike a rigid bony skeleton, the structure of the grey reef shark (and of all sharks and rays in general) is flexible and maneuverable thanks to the cartilage in it, allowing the shark to bend its body and move in ways it wouldn’t be able had it possessed a bony skeleton. This cartilage allows the shark to evade predators and find prey much more easily. Also, like all sharks, the grey reef shark has a mouth with rows of teeth which are serrated and triangular. Sharks (and rays) replace their teeth like a conveyer belt: as the teeth in the front row fall out, the teeth behind them move forward to take their place.
The maximum length for males is 2.6 meters (8.4 feet) and for females is 1.7 meters (5.6 feet). Their weight ranges from 20—30 kilograms (44—66 pounds).
Their diet consists of fishes, crustaceans (crab, lobsters, and shrimp), and cephalopods (squid and octopus).
This species of shark gives birth to live young and reproduces by internal fertilization. When the female is ready to mate (age of maturity is between seven and eight years old), she releases chemical substances called pheromones into the water. Both the male and female give behavioral cues that involve the male performing a dance and the female swimming away until the male lunges at the female and seizes her with his teeth before they mate. Fortunately, females have thicker skin on their backs, possibly for this exact reason.
Male sharks use claspers (reproductive structures located between their pelvic fins) to direct sperm into the female. The sperm can fertilize the egg at the time of mating or can be stored until an egg is released. Gestation (development) lasts twelve months. Female grey reef sharks produce one to six offspring each time.
During the day, grey reef sharks will form aggregations or schools. However, these sharks are more active at night. They are slow swimmers and may be territorial. They have a distinct agonistic display (a behavior related to fighting) in which they arch their backs, point their pectoral fins (side fins) downward, and swing their heads sideways in a slow motion as they swim. Grey reef sharks are known to be curious and often approach divers.
Like all elasmobranchs (sharks and rays), grey reef sharks exhibit a form of camouflage known as countershading, in which their dorsal side (back side) is darker than their ventral side (underside). Countershading helps the shark appear less visible to both predators and prey from above and below, allowing them to find prey and evade predators more easily. Additionally, this species has excellent senses, especially its sense of smell. They use a system of organs that run along their sides called the lateral line to detect movement and pressure changes in the water around them. They also use tiny gel-filled pores around their snouts called ampullae of Lorenzini to detect electromagnetic signals to navigate and find prey.
The lifespan for this species is estimated to be about twenty-five years.
According to the International Union for Conservation of Nature (IUCN), the grey reef shark is considered Endangered because of its habitat choice, coastal distribution, high fidelity (faithfulness) to a particular site, small litter size, and slow maturity rate. It is subject to overfishing as they are used for a wide variety of human consumption, from shark fin soup to fishmeal to other shark-filled products. Because this shark species matures at a slow rate, they are unable to reproduce fast enough to combat overfishing.
The grey reef shark’s coral reef habitat is also affected by global climate change and destructive fishing practices such as dynamite fishing (fishing that utilizes explosives, resulting in a larger catch) and declining water quality.
Fortunately, conservation efforts are being made for the grey reef shark (and all sharks in general). One way is by utilizing marine protected areas or MPAs, parts of the ocean that the government has set aside for marine life and that limit human activity. Another way is by managing commercial and recreational shark fisheries and working with fishery management councils to conserve and manage sharks in a sustainable way. Restrictions on shark harvests are also being implemented. Educating the public about how human practices like overfishing, shark consumption, and dynamite fishing habitat affects sharks and their habitat is yet another way we can help save sharks.
When hunting for prey, grey reef sharks can reach speeds of up to 40.2 km/hr (25 mph).
A typical shark may lose up to 30,000 teeth in its lifetime.