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Temp: Surf 25°C Bottom 26°C
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Dive type : Recreational, Reef
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Visibility: Average
Water: Salt
Recent Divers in Great Barrier Reef Flynn Reef
Recent Pictures in Great Barrier Reef Flynn Reef
Dive Profile
- 1. Air
- 11L Aluminium
220 → 110 bar
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- Average depth: 6.8m
- SAC: 1.26 bar/min
- RMV: 14.364 L/min
Data provided by EOL.org
Species Identified
Chelonia mydas Linnaeus 1758 (Green Turtle)
Green turtles are long-lived and may take up to 59 years to reach sexual maturity Undertaking tremendous feats of navigation, adults return to the same beach to breed each season, part of the population in Brazil astonish...
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Green turtles are long-lived and may take up to 59 years to reach sexual maturity Undertaking tremendous feats of navigation, adults return to the same beach to breed each season, part of the population in Brazil astonishingly migrates around 2,250 kilometres across the open ocean to breed on the Ascension Islands . Mating tends to occur just offshore of the nesting beaches; using a curved claw on each front flipper and a flat nail at the end of the tail, males are able to grip their mates . Females haul out onto the beach at night and dig large nests with their back flippers beyond the high tide mark, they typically lay between 100 and 150 eggs in one nest and then proceed to cover the eggs with sand; the whole process takes around two hours . A single female returns to breed only once every two to five years but will lay up to nine nests in that one season . Incubation takes between 45 and 70 days, and temperature has been shown to determine of the sex of hatchlings; with females being produced at warmer temperatures . Breaking open their eggs with a special hooked 'egg tooth' that will subsequently be lost; hatchlings use their powerful front flippers to reach the surface, and then proceed to the sea . The soft-bodied juveniles are particularly vulnerable at this time from a variety of predators, such as ghost crabs and gulls on the beach to sharks and dolphins in the water . Unlike other marine turtles, adult green turtles are almost exclusively herbivorous, grazing on seagrasses and algae ; it is assumed that juveniles are more omnivorous although the exact composition of their diet is unknown
Eretmochelys imbricata (LINNAEUS) 1766 (Hawksbill Turtle)
Hawksbills may take decades to mature and it could be between 20 to 40 years before they are ready to breed . Upon reaching sexual maturity, a female will typically lay up to five clutches of around 100 to 140 eggs in one ...
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Hawksbills may take decades to mature and it could be between 20 to 40 years before they are ready to breed . Upon reaching sexual maturity, a female will typically lay up to five clutches of around 100 to 140 eggs in one breeding season, and then wait a few years before nesting again . Nesting is much more dispersed than in other marine turtles, but individuals do tend to return to a particular beach season after season . Having survived the dash to the sea, hatchlings are believed to spend their first few years in the open ocean before returning to more sheltered coastal waters. Recent studies indicate that the oceanic phase may be shorter for hawksbills, or even omitted in certain regions, as hatchlings swim less vigorously than those of other species . Probably less than one out of 1000 eggs will survive and reach adulthood . Adults are opportunistic predators, using their sharp beak to prize invertebrate prey from crevices within the reef. Unusually amongst marine animals , sponges make up the majority of the hawksbill's diet .
Triaenodon obesus (Rüppell, 1837) (Whitetip reef shark)
Despite its docile nature during the day this nocturnal shark can become aggressive when hunting at night, thrashing through coral reefs looking for potential prey. The whitetip reef shark usually hunts alone, but is non-t...
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Despite its docile nature during the day this nocturnal shark can become aggressive when hunting at night, thrashing through coral reefs looking for potential prey. The whitetip reef shark usually hunts alone, but is non-territorial and will occasionally work in cooperation with others in the pursuit of prey . Feeding primarily on bottom-dwelling octopus, lobsters, crabs and bony fish, it often chases its prey into a crevice before jamming its body in after it, sealing the exit . The extremely posterior location of the first dorsal fin compared to those of other sharks is an adaptation to this feeding habit, which allows them to get their heads and mouths much further into the gaps and holes in the coral . The whitetip reef shark's mating season varies with location . Reproduction is viviparous and after a gestation period of around a year the female will give birth to one to five live pups, which are completely independent at birth . Both sexes reach sexual maturity at approximately 5 years old, and it is estimated that this species can live to an age of 25 years .
Cheilinus undulatus Rüppell, 1835 (Humphead wrasse)
Humphead wrasses are extremely long-lived, known to survive for at least 30 years, and taking around five to seven years to reach sexual maturity . Adults are usually solitary, spending the day roaming the reef and returni...
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Humphead wrasses are extremely long-lived, known to survive for at least 30 years, and taking around five to seven years to reach sexual maturity . Adults are usually solitary, spending the day roaming the reef and returning to particular caves or ledges to rest at night . Very little is known about these fish; adult females are able to change sex but the triggers for this development are not known . Pairs spawn together as part of a larger mating group that may consist of over 100 individuals. The planktonic eggs are released into the water and once the larvae have hatched they will settle out on the substrate . Using their tough teeth, these fish are able to consume hard-shelled species such as molluscs, echinoderms and crustaceans . They are one of the few predators of species that destroy coral reefs, such as the infamous crown of thorns starfish (Acanthaster planci) .
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Matthias
Australia
Date: 2012-05-11 - 11:51
Max Depth: 11.4m Duration: 52mins
Turtles
White-tip reef shark
Barracuda