| Mangrove red snapper | |
|---|---|
 | |
| Lutjanus argentimaculatus off SouthernTaiwan | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Acanthuriformes |
| Family: | Lutjanidae |
| Genus: | Lutjanus |
| Species: | L. argentimaculatus |
| Binomial name | |
| Lutjanus argentimaculatus (Forsskål, 1775) | |
| Synonyms | |
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Themangrove red snapper (Lutjanus argentimaculatus), also known asmangrove jack,grey snapper,creek red bream,Stuart evader,dog bream,purple sea perch,red bream,red perch,red reef bream,river roman, orrock barramundi (though it is not closely related tobream,jack, orbarramundi), is a species of marineray-finned fish, a snapper belonging to thefamilyLutjanidae. It has a wideIndo-Pacific range and has recently beenrecorded in the eastern Mediterranean Sea.
The mangrove red snapper was first formallydescribed in 1775 asSciaena argentimaculata by theSwedish speakingFinnish-bornexplorer andnaturalist Peter Forsskål with thetype locality given as the Red Sea.[2] The specific name is a compound ofargentum meaning “silver” andmaculatus meaning “spots”, a possible reference to the white edging to each of the scales on this species.[3]
Coloration of the mangrove red snapper ranges fromburnt orange, tocopper, tobronze and dark reddish-brown, depending on its age and environment. Younger fish caught inestuarine areas are often darker than older fish taken from offshore reef areas,[4] and exhibit lighter verticalbands down theirflanks. The maximum recorded length is 150 centimetres (4.9 ft), but 80 centimetres (2.6 ft) is most common.[5]Like other tropical snappers (family Lutjanidae), mangrove jacks have prominentfangs in their jaws that are used for seizing and holding prey, akin to thecanine teeth of a mammal. These teeth can cause a nasty injury to unwary fishers.[6]
In reef areas, mangrove red snappers are sometimes confused withtwo-spot red snapper or red bass (Lutjanus bohar), a known carrier ofciguatera toxin. The red bass, however, is usually darker in coloration, has fewer dorsal-fin spines, scale rows on the back that rise obliquely from the lateral line, and a deep groove from the nostrils to the eyes.[6][clarification needed]
The mangrove red snapper is native to theIndian Ocean and the westernPacific Ocean from theAfrican coast toSamoa and theLine Islands and from theRyukyus in the north toAustralia in the south. It has also rarely been recorded in theMediterranean Sea, having undergoneLessepsian migration from theRed Sea since at least 1979.[7]
As its name implies, the mangrove red snapper is commonly found inmangrove-linedestuarine systems, however some make their way into completefreshwater systems, particularly at a juvenile age. They migrate to offshore reefs to spawn. As they mature, mangrove red snappers move into open waters, sometimes hundreds of kilometers from the coast[8] to breed. These larger fish are sometimes caught bybottom-fishers withheavy tackle, though they remain difficult to land due to their speed and proximity to sharp reef bottoms.[citation needed]
The species is carnivorous; they arepredators, feeding mainly at nighton fish,crustaceans,gastropods, andcephalopods.[6] Asambush predators, they often dwell around mangrove roots, fallen trees, rock walls, and any other snag areas where smaller prey reside for protection.
Like many marine fish, the mangrove red snapper is abroadcast spawner. Spawning occurs during theaustral spring-summer seasons in NortheasternQueensland, "[beginning] around October, peaked in December and then declined over summer from January through March."[sic]; conversely, it occurs duringboreal autumn in Thailand from late September to November. Both of these periods coincide withhigh rainfall and decreasing water temperature, which may result in nutrients being flushed into inshore waters from alluvialrunoff. Due to the continuing presence of juveniles in March and April, Thai mangrove jacks may continue spawning during the boreal springtime. Mangrove jacks inPalau were observed to form spawningaggregations in reeflagoons and outer reef slopes. Spawning is influenced by thelunar cycles - akin to a number of otherlutjanids - peaking between days 14 and 18 of thelunar month, or around thefull moon; this appears to be a method to give the subsequenteggs and larvae the most advantageoustides for survival.[9]
A 4.6 kilograms (10 lb) female may produce 1.3 million eggs, which are transparent, pelagic, and do not adhere tosubstrate (e.g non-adhesive). The eggs started undergoingmitosis 1.5 hours after spawning, theembryo formed 12 hours hence, and they hatched after 16 hours of development at 28 °C (82 °F) and 32pptsalinity. 72 hours after hatching, yolk resorption is complete, and thelarvae begin feeding. The growth of the larvae is slow in the first week of life, but greatly accelerates in the subsequent two weeks.[10] Immature fish are found ininshore areas, including rivers, while mature fish tend to be caught offshore. Males matured at somewhat smaller sizes than the females: Lm₅₀ (length where 50% of fish sampled were mature) for females was 531.4 mmFL, while for male fish it was 470.7 mm FL.[9] Themaximum reported age is 31 years.[5]
Mangrove red snapper is a popular and importantcommercial andrecreational fish throughout its range, and considered to be an excellentfood fish,[6] which allows it to command a relatively highmarket price.[10]
For fishermen, the telltale sign of a hooked mangrove red snapper is the explosive run for cover once the bait (or lure) is taken. Many fish (and so lures) are lost once they reach the protection of the snags as a result of their initial burst of speed.
InSoutheast Asia, these fish areaquacultured; the fry are collected from the wild, and reared to market size inbrackish-water floating net cages andponds.[10] During the turn of thenew millennium, efforts were made to improve production of aquacultured mangrove jacks, and the reproductive mechanisms of the fish were discovered, along with effective methods for induced spawning through hormonal injection.[12]
The mangrove red snapper is a highly regarded table fish with firm, sweet-tasting, white flesh. While often a nuisance species when targeting the infamousbarramundi, many fisherman rate the eating qualities of the jack higher than it.
