triggerfish

Triggerfish
Titan triggerfish (Balistoides viridescens)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Tetraodontiformes
Family:	Balistidae
Genera
See text.

Triggerfishes are various, often brightly colored fish of the family Balistidae. Often marked by lines and spots, they inhabit warm coastal waters of the Atlantic, Mediterranean and the Indo-Pacific.

Anatomy and appearance

Triggerfish have an oval, highly compressed body. The head is large, terminated in a small but strong- jawed mouth with teeth adapted for crushing shells. The eyes are small, set far back from the mouth, at the top of the head. The anterior dorsal fin is reduced to a set of three spines. The first spine is stout and by far the longest. All three are normally retracted into a groove. The ventral and the posterior dorsal fins are capable of undulating from side to side to provide slow speed movement. The sickle shaped caudal fin is used only to escape predators. The two pelvic fins are overlaid by skin for most of their length and fused to form a single spine, terminated by very short rays, their only external evidence. Gill plates operculum too, although present are not visible, overlaid by the tough skin, covered with rough, rhomboid scales, that forms a stout armor on their body. The only gill opening is a vertical slit, directly above the pectoral fins. This peculiar covering of the gill plates is shared with other members of the Tetradontae order. Each jaw contains a row of four teeth on either side, while the upper jaw contains an additional set of six plate-like pharingeal teeth.[1] As a protection against predators, Triggerfish can erect the first two dorsal spines: The first, (anterior) spine is locked in place by erection of the short second spine, and can be unlocked only by depressing the second, “trigger” spine, hence the family name “Triggerfish”. Adult Triggerfish of the various species found worldwide, range in size from 8 inches to 3 feet long (20 to 90 cm).

Behavior

The rather bizarre anatomy of the triggerfish reflects its diet of slow-moving, bottom dwelling crustaceans, mollusks, sea urchins and other echinoderms, generally creatures with protective shells and spines. Triggerfish are usually found over hard bottom where such prey occur. Some triggerfish species can be quite aggressive when guarding their eggs. Both Picasso and Titan triggerfish viciously defend their nests against intruders, including scuba divers and snorkelers. Their territory extends in a cone from the nest toward the surface, so swimming upwards can put a diver further into the fishes' territory; a horizontal swim away from the nest site is best when confronted by an angry triggerfish. Unlike the relatively small Picasso triggerfish,the titan triggerfish poses a serious threat to inattentive divers due to its large size and powerful teeth. Triggerfish are notorious bait stealers; rather than swallowing a bait whole, they nibble off small bites of it, making a small, stout hook essential to success in hooking them. Accordingly, the best baits are tough strips of fish skin, squid mantle etc.

Edibility

Triggerfish, at least the Gray Triggerfish (Balistes Carolinensis) found off the east coast of Florida, are excellent table-fare. Their flesh is white, firm and flavorful, with only a few bits of red flesh which may be scraped off easily at the base of the ventral and posterior dorsal fins. Triggerfish should be eaten in the form of skinless fillets; the stout, totally inedible skin may be removed by puncturing the skin with a sharp-pointed knife, and cutting the skin from the inside to avoid having to cut the scales.

Life history

Triggerfish lay their demersal eggs in a small hole dug in the sea bottom. Off Florida, juvenile Triggerfish are found in floating sargassum, where they feed on the small shrimp, crabs and molluscs found there. ^[1]

Picasso triggerfish bite

Titan triggerfish moving rocks from its nest by picking them up with its large front teeth.

Gallery

Queen triggerfish, Long Cay, Belize	Clown triggerfish, New Hanover Is., Papua New Guinea	Boomerang triggerfish, Kona, Hawaii	Picasso triggerfish (Rhinecanthus aculeatus)
Redtoothed triggerfish (Odonus niger) feeding on plankton	Titan triggerfish (Balistoides viridescens) with orange-lined triggerfish (Balistapus undulatus) and moorish idols at the reef of Fihalhohi, Maldives	Orange-lined triggerfish (Balistapus undulatus)	Indian triggerfish (Melichthys indicus) and its reflection in the water surface
Halfmoon triggerfish	Pinktail triggerfish	Rhinecanthus rectangulus feeding on invertebrates in the sand

Genera

• Abalistes Bloch & Schneider, 1801
  • Abalistes stellaris : Starry triggerfish
• Balistapus Tilesius, 1820
  • Balistapus undulatus : Orange-lined triggerfish
• Balistes Linnaeus, 1758
  • Balistes capriscus: Grey triggerfish
  • Balistes ellioti
  • Balistes polylepis : finescale triggerfish
  • Balistes punctatus : Bluespotted triggerfish
  • Balistes rotundatus
  • Balistes vetula : Queen triggerfish
  • Balistes willughbeii
• Balistoides Fraser-Brunner, 1935
  • Balistoides conspicillum : Clown triggerfish
  • Balistoides viridescens  : Titan triggerfish or mustache triggerfish
• Canthidermis Swainson, 1839
  • Canthidermis maculata: Spotted oceanic triggerfish
  • Canthidermis macrolepis : Large-scale triggerfish
  • Canthidermis sufflamen : Ocean triggerfish
• Melichthys Swainson, 1839
  • Melichthys indicus : Indian triggerfish
  • Melichthys niger : Black triggerfish
  • Melichthys vidua : Pinktail triggerfish
• Odonus Gistel, 1848
  • Odonus niger : Redtoothed triggerfish
• Pseudobalistes Bleeker, 1865
  • Pseudobalistes flavomarginatus Yellowmargin triggerfish
  • Pseudobalistes fuscus : Blue or rippled triggerfish, blue-and-gold triggerfish or yellowspotted triggerfish
  • Pseudobalistes naufragium : Stone triggerfish
• Rhinecanthus Swainson, 1839
  • Rhinecanthus abyssus
  • Rhinecanthus aculeatus Picasso triggerfish, lagoon triggerfish (USA)
  • Rhinecanthus assasi : Arabian Picasso triggerfish
  • Rhinecanthus cinereus
  • Rhinecanthus lunula : Halfmoon picassofish
  • Rhinecanthus rectangulus: Reef triggerfish or humuhumu-nukunuku-a-pua'a (Hawaii)
  • Rhinecanthus verrucosus : Blackbelly triggerfish
• Sufflamen Jordan, 1916
  • Sufflamen albicaudatum : Bluethroat triggerfish
  • Sufflamen bursa : Boomerang triggerfish
  • Sufflamen chrysopterum : Halfmoon triggerfish
  • Sufflamen fraenatum : Masked triggerfish
  • Sufflamen verres : Orangeside triggerfish
• Xanthichthys Kaup in Richardson, 1856
  • Xanthichthys auromarginatus : Gilded triggerfish
  • Xanthichthys caeruleolineatus : Bluelined triggerfish
  • Xanthichthys lineopunctatus : Striped triggerfish
  • Xanthichthys mento : Redtail triggerfish
  • Xanthichthys ringens : Sargassum triggerfish
• Xenobalistes Matsuura, 1981
  • Xenobalistes punctatus : Outrigger triggerfish
  • Xenobalistes tumidipectoris

References

• "Balistidae". FishBase. Ed. Rainer Froese and Daniel Pauly. December 2005 version. N.p.: FishBase, 2005.

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