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Species Identified
Epinephelus marginatus (Lowe, 1834) (Duskey grouper)
The dusky grouper is a protogynous hermaphrodite, meaning that it matures as a female but later develops into a male as it grows larger and older . Sexual maturity is attained fairly late, when females are around five year...
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The dusky grouper is a protogynous hermaphrodite, meaning that it matures as a female but later develops into a male as it grows larger and older . Sexual maturity is attained fairly late, when females are around five years of age, while sex reversal of females into males takes place between the 9th and 16th year, peaking at 12 . The grouper usually leads a solitary and relatively sedentary life, except during the breeding season when small clusters of a few tens of individuals form at specific spawning sites . The spawning season in the Mediterranean is from June to September , mating is polygynous and aggregations generally have a female bias of around seven females to each male . During this period, dominant males establish territories and demonstrate strong territorial behaviour, acting aggressively towards neighbouring males and smaller females . The maximum reported age of a dusky grouper was about 50 years . Diet consists of crustaceans, molluscs and fish, with diet varying with body size . While younger, smaller groupers feed primarily on crustaceans, larger individuals feed on a greater proportion of fish, with the majority being reef-associated species .
Heterodontus portusjacksoni (Meyer, 1793) (Port Jackson shark)
A common shark of the continental shelves , from close inshore at the intertidal zone to 275 m . Segregates by sex and maturity stage . Nocturnal, hides in caves and rocky gullies during the day . Feeds on benthic inver...
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A common shark of the continental shelves , from close inshore at the intertidal zone to 275 m . Segregates by sex and maturity stage . Nocturnal, hides in caves and rocky gullies during the day . Feeds on benthic invertebrates, primarily echinoderms . Oviparous . Eggs with spiral flanges but lack tendrils . Undergoes yearly migrations to spawning sites during breeding season . Considered harmless to people, but can deliver a painful nip when provoked .
Orectolobus maculatus (Bonnaterre, 1788) (Wobbegong)
The sluggish spotted wobbegong spends much of its day lying motionless on the bottom or hidden in caves, under overhangs or in shipwrecks. At night, the shark becomes more active, and swims, or moves about the sea floor, ...
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The sluggish spotted wobbegong spends much of its day lying motionless on the bottom or hidden in caves, under overhangs or in shipwrecks. At night, the shark becomes more active, and swims, or moves about the sea floor, searching for prey to slowly sneak up on . Bottom-dwelling animals such as reef fishes, octopuses, crabs and rock lobsters are some of their preferred foods , many of which blunder unwittingly towards the mouth of the camouflaged wobbegong. By opening its wide mouth and expanding its throat, the wobbegong can effectively suck in its prey, trapping and killing it with its powerful jaws and big teeth. After a night spent hunting, the spotted wobbegong, which is observed singly or in aggregations, often returns to the same resting site . The nocturnal spotted wobbegong is an ovoviviparous shark, thus the embryos develop inside eggs that remain inside the mother until they hatch. Females give birth to large litters, usually of around 20 pups, but up to 37 pups have been recorded .
Pterapogon kauderni Koumans, 1933 (Banggai cardinal fish)
The Banggai cardinalfish is remarkable among marine fishes for the extreme levels of genetic diversity found between its populations. Populations as little as five kilometres apart are as genetically distinct as separate s...
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The Banggai cardinalfish is remarkable among marine fishes for the extreme levels of genetic diversity found between its populations. Populations as little as five kilometres apart are as genetically distinct as separate species, a consequence of the Banggai cardinalfish's highly limited dispersal capability, the strong currents and deep channels between the islands preventing interaction with populations at other sites . Banggai cardinalfish live in small groups of usually between 1 and 6 individuals, though a group of 500 has been recorded . Reproduction in the Banggai cardinalfish begins with the female choosing a male; the pair then separate from the group and establish a territory, aggressively defending it from other fish that come too close. The female then initiates an unusual courtship ritual, swimming alongside the male, bodies touching, and making a trembling motion. This behaviour occurs repeatedly on both sides, with the only signs of the male's receptivity being a darkening of the lower jaw and an occasional opening of the mouth . After several hours of this behaviour, the female spawns a mass of up to 75 large eggs . These are quickly swallowed by the male, and brooded in a special pouch inside the mouth . The eggs take about 20 days to hatch, after which, the newly hatched embryos continue to develop in the male's mouth pouch. After a further 10 days, when the young have reached around five to six millimetres in length, they are released . During the 30-day brooding period the male does not eat, and attends to the brood by frequently turning the eggs and expelling dead eggs and embryos. Once the brood are released, the male does not interact with them anymore . The small juveniles are most commonly found sheltering around sea anemones for protection. However, older juveniles and adults are more commonly found around branching corals and sea urchins . The Banggai cardinalfish feeds principally upon tiny planktonic crustaceans, with copepods, in particular, making up about 80 percent of the diet. Nevertheless, this species is an opportunistic feeder, and will take a variety of small organisms from the water column and the seabed, including marine worms, molluscs and fish larvae. In addition, it plays an important role in its environment by preying on the larval stages of coral reef fishes' parasites . The Banggai cardinalfish is preyed upon by various species, such as the crocodile-fish (Cymbacephalus beauforti), various lion-fish species (genus Pterois) and the grouper (Epinephelus merra) . This species may live for two years in the wild
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Sistabron
Australia
Date: 2012-04-29 - 11:00
Max Depth: 12m Duration: 55mins
