Balistes vetula

Family : Balistidae

 

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Text © Giuseppe Mazza

 

 

English translation by Mario Beltramini

 

 

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Balistes vetula reaches the 60 cm and is at home on both coasts of the Atlantic © Giuseppe Mazza

The Queen triggerfish ( Balistes vetula - Linnaeus, 1758 ) belongs to the class of the Actinopterygii, the ray-finned fishes, to the order of Tetraodontiformes and to the family Balistidae, the so-called triggerfishes.

The name of the genus comes from the Latin “balista” = crossbow, with reference to this weapon due to the arcuate shape of the fins and the trigger, ready to spring, the fish has on the back.

The name of the species comes from the Latin “vetula” = little old lady, maybe due to the traits forming almost some wrinkles, especially close to the eyes.

Zoogeography

It is at home in the tropical and temperate waters of the Atlantic Ocean. We find it at Capo Verde, the Acores and along the African coasts from Morocco to Angola. Then, at Ascension Island and on the other side of the ocean from Canada and the Gulf of Mexico and Caribbean up to Brazil.

Ecology-Habitat

It lives in the rocky and madreporic formations up to almost 300 m of depth, but usually is found between the 3 and the 30 m.

Morpho-physiology

The queen triggerfish may reach the 60 cm. The body is fairly flat, shaped like a crossbow, with the eyes placed up on the head, independent from each other in the movements, like the chameleons.

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It cares its eggs, building a nest, but is an endangered species © Giuseppe Mazza

On the back we note at once the famous erectile trigger formed by three spines. It is often folded, but the fish may shoot it out and block it in erect position in order to resist to the predators, wedged between the rocks or simply for calmly sleeping, without risking to be taken away by the currents, in grottos with narrow entrance, where the passage is possible only with the fin folded. But the main function is of dissuasion: seen that it keeps open also when dead, it would not be by sure a nice experience for the tunas and sharks turning around.

The second dorsal fin has 29-32 soft rays and is almost specular to the anal one which has 27-29 of them. The pectoral fins count 13-15 unarmed rays and the ventral are absent. The caudal is lunate with elongated margins in the adults.

The body contains some blue, violet, green and turquoise, depending on the zone, the mood and the age of the fish. In any case, the throat is yellow with two luminous blue traits over the mouth and lips equally circled by blue. Often are evident some dark oblique traits on the back and some more marked patterns spreading like wrinkles from the eyes, whence, as we said, the Latin epithet of little old lady.

The mouth is robust, armed by solid incisors, good for holing shells, armours and importuners.

Ethology-Reproductive Biology

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The males are territorial. They control a zone of about 10 m and allow only the females to enter the same © Giuseppe Mazza

The queen triggerfish is found often in proximity of the bottom where it hunts crustaceans, molluscs and especially echinoderms. It loves the sea urchins and in particular the Diadema antillarum, that it finds in most of its biotope.

For eating it, uses its own technique: it turns it upside down, by blowing under it water with the mouth, and then attacks it ventrally without incurring the long spines.

It seems that it does not disdain also some sea weeds.

The males are territorial. They control a zone of about 10 m and allow only the females to enter the same.

By the time of the reproduction they remove the sand of the bottom with the fins and strong jets of water, as for the sea urchin, in order to create a cavity shaped like a bowl. This is the nest where the female will spawn, the eggs being fecundated at once by the husband, and where, until the hatching, the spouses will keep watch sending away the importuners, scuba divers included, who often surface bleeding with deep bites.

Despite these cares, the species is endangered. In fact, the queen triggerfish accidentally runs into the nets of the industrial fishing, and, aquaria apart, it is sought for its excellent flesh, even if some organs, such as the liver, are poisonous. The populations could double in 1,4-4,4 years, but the vulnerability index is nowadays of 36 per 100.

Synonyms

Balistes bellus - Walbaum, 1792; Balistes equestris - Gronow, 1854; Balistes vetula trinitatis - Nichols & Murphy, 1914.

 

→ For general information about fishes please click here.

→ To appreciate the biodiversity within the Osteichthyes, the BONY FISH, and find other species, please click here.

 

The photographic file of Giuseppe Mazza

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