The leopard coral grouper ( Plectropomus leopardus), also known as the common coral trout, leopard coral trout, blue-dotted coral grouper or spotted coral grouper, is a species of marine ray-finned fish, a grouper from the subfamily Epinephelinae which is part of the family Serranidae, which also includes the Anthiinae and sea basses. It is found in the Western Pacific Ocean.
Coral trout are the favourite target fish for all sectors of the fishery because they are a good food fish and command high market prices locally and overseas. The total commercial catch of coral trout was reported at over 1500 tonnes in 1998.
Description
Distribution
Habitat and biology
Reproduction
spawning corresponds to an increase in water temperature (from ) during late spring. In the northern Great Barrier Reef, these fish spawn between September and December, whereas in the southern regions where the water is cooler, spawning occurs between October and February. The beginning and end of spawning can vary from year to year as the water temperature varies. Leopard coral groupers generally form into a dense aggregation to spawn. These aggregations are formed around reef slopes around deep and peak at the new moon. Spawning occurs when the tidal flow is strong, particularly during ebb tides. This is thought to allow the newly released eggs to be transported well away from the reef and its associated predators. Spawning typically takes place at dusk, when the light levels make it difficult for to see and feed upon the eggs.
As coral trout aggregate, males establish temporary territoriality. They then try to entice females into their territories to spawn by means of elaborate courtship displays. As part of this courtship ritual, male coral trout display their ' darkened edges, which can be switched on and off almost instantly. The male approaches a female, which is usually close to the bottom, with his body tilted at 45–90° (almost lying on his side in the water) and repeatedly quivering lengthwise and shaking his head from side to side. He passes close to the female's head or body with either the top or underside of his body. This process is repeated. Spawning rushes occur after this courtship behavior, if the female agrees. During a spawning rush, the male and female swim rapidly towards the surface, where they release sperm and eggs into the water as they quickly turn. The cloud of sperm and eggs released during a spawning rush is not easily seen, but its presence can sometimes be noted by the frantic feeding of small zooplankton-eating fish. The spawning of coral trout generally occurs over a 30-40 minute period during sunset. Some coral trout (especially males) spawn more than once during an evening.
The fastest period of growth in coral trout occurs in the first three years of life. The average daily growth of newly settled juveniles has been measured at 0.81 mm per day. This means they reach close to in the first 6 months. Growth rates of coral trout are variable; every age class has a wide range of sizes. To estimate growth, the age and size of a fish must be determined. Most commonly, the growth of fish is measured by collecting individuals of varying sizes, measuring their length, and determining their age by the otoliths. Recent research at Bramble Reef has found that common coral trout ( P. leopardus) reaches a maximum age of 16 years.
Coral trout in the southern Great Barrier Reef feed mainly on parrot fish (family Scaridae) and hardyhead bait fish (family Atherinidae). The most common prey items further north are the damselfish (Pomacentridae) and fusiliers or banana fish (Caesionidae). One study showed coral trout eating schools of fusilers in summer, and scarids during the winter. This seasonal variation is quite common in the diet of coral trout due to varying abundances of prey at different times of the year. Trout also tend to eat more food in winter, possibly to increase fat stores in preparation for reproduction in spring. They sometimes engage in cooperative hunting with the giant moray ( Gymnothorax javanicus), the humphead wrasse ( Cheilinus undulatus), or the big blue octopus ( Octopus cyanea).Vail A.L., Manica A., Bshary R., Referential gestures in fish collaborative hunting, in Nature Communications, vol. 4, 2013. Il pesce che quando va a caccia "balla" per chiamare rinforzi in National Geographic
It is Cyanide fishing in the Philippines and Indonesia. In Fiji and New Caledonia artisanal fishers catch it using hook and line and spear, and as bycatch in traps. Large specimens can have very high levels of ciguatoxin in their flesh. Fish have been raised in mariculture in Asia but cultured fish are often not the more desirable red colour.
Life cycle
Diet
Parasites
Taxonomy
Utilisation
External links
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