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Temp: Surf 30°C Bottom 29°C
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Dive type : Recreational, Deep dive
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Visibility: Excellent
Water: Salt
Specific gear used
- Computer: Suunto - Zoop
- Mask: beuchat - cousteau
- Wet suit: Mares -
- Fins: Mares -
- BCD: Scubapro - t black
- Camera: GOPRO - hero3
- Regulator: Mares -
- Weights: 2 kg
Recent Pictures in Tahiti
Dive Profile
- 1. Air
- 12L Steel
220 → 40 bar
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- Average depth: 19.9m
Data provided by EOL.org
Species Identified
Negaprion brevirostris (Poey, 1868) (Lemon shark)
The lemon shark has been the subject of one of the most long-term and intensive studies on a shark species. Much of what is known about this shark is due to the work of Dr Samuel Gruber and his colleagues. This predator ...
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The lemon shark has been the subject of one of the most long-term and intensive studies on a shark species. Much of what is known about this shark is due to the work of Dr Samuel Gruber and his colleagues. This predator is most active at dawn and dusk, and occurs singly or in loose aggregations of up to 20 individuals. It feeds primarily on fishes, including sea catfishes, mullet, stingrays and eagle rays, but also on crustaceans and molluscs. During the day they often lie quietly on the seabed, apparently resting, but in reality this behaviour uses up more energy than when swimming, due to the extra effort required to pump water over the gills . Therefore, they may be lying motionless waiting for wrasses or other small reef fishes to clean them of any parasites . The lemon shark is viviparous; the embryos develop inside the mother and receive nutrients via a yolk sac placenta. After a gestation period of 10 to 12 months, pregnant females enter shallow nursery areas in spring and summer to give birth to litters of 4 to 17 pups. The pups have a very slow growth rate and remain within nursery grounds for a considerable length of time, where they are less vulnerable to predation by larger sharks . The mangroves that the young frequently inhabit are highly productive waters, creating a marvellous site for feeding, but also an area of very low oxygen content. Luckily, the lemon shark has numerous adaptations that enhance oxygen uptake, such as blood with an unusually high affinity for oxygen, and thus the pups can lie feeding in the rich waters, protected from any large potential predators by the mangrove's tangled roots . As they grow, their range expands dramatically, from six to eight kilometres up to around 300 kilometres. Maturity is reached at about six and a half years of age, and it is believed that the lemon shark lives for up to 27 years .
Ginglymostoma cirratum (Bonnaterre, 1788) (Nurse shark)
During the day the nurse shark is a sluggish animal, spending most of its time resting on sandy bottoms, or in crevices in rocks and coral reefs. Often several nurse sharks may congregate when resting, sometimes even pili...
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During the day the nurse shark is a sluggish animal, spending most of its time resting on sandy bottoms, or in crevices in rocks and coral reefs. Often several nurse sharks may congregate when resting, sometimes even piling on top of one another . At night however, the nurse shark actively roams the sea bottom and reef for prey. It feeds on bottom invertebrates such as spiny lobsters, shrimps, crabs, sea urchins, squid and octopi . It is also feeds on fish, its nocturnal nature enabling it to prey on resting fish that would be too active during the day to capture . The nurse shark's small mouth and large pharynx enable it to feed by a unique suction method, effectively making the nurse shark the 'hoover' of the ocean floor. By cupping its mouth over a hole or crevice and expanding its throat, it creates a vacuum that sucks prey out of their hiding . This suction-feeding is also useful for extracting snails from their shells , and it will dig in sand to root out prey sensed by its fleshy barbels . The nurse shark is one of few sharks in which courtship behaviour is relatively well known . The male swims alongside the female, grabs one of the pectoral fins in his mouth, rolls her over and they mate . A large number of males will often try to mate with a single female, and females often bear numerous bite-scars and bruises received during mating attempts. It is therefore not surprising that females frequently try to avoid males by swimming in very shallow water, where they can bury their pectoral fins in the sand . Nurse sharks are ovoviviparous , a method of reproduction whereby the young develop inside a weakly-formed egg shell within the mother, receiving nourishment from their yolk sac, for five to six months . The females move to shallow seagrass beds and coral reefs to give birth to 20 to 30 pups in late spring and summer . Like many sharks the nurse shark is slow growing, with males not reaching maturity until 10 to 15 years of age, and females 15 to 20 years .
Gymnosarda unicolor (Rüppell, 1836) (Bonito)
An offshore species found mainly around coral reefs. Generally solitary or occur in small schools of six or less. Preys on small schooling fishes such as Decapterus, Caesio, Nasio, Cirrhilabrus, Pterocaesio and squids. Marketed canned and frozen . Adults may be ciguatoxic .
An offshore species found mainly around coral reefs. Generally solitary or occur in small schools of six or less. Preys on small schooling fishes such as Decapterus, Caesio, Nasio, Cirrhilabrus, Pterocaesio and squids. Marketed canned and frozen . Adults may be ciguatoxic .
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David Hsl
French Polynesia
Date: 2016-04-16 - 08:30
Max Depth: 45.1m Duration: 50mins
Dive with Vincent from Topdive Tahiti
