Helicolenus dactylopterus

Family : Sebastidae

Text © Giuseppe Mazza

 

English translation by Mario Beltramini

 

The Blackbelly rosefish (Helicolenus dactylopterus Delaroche, 1809) belongs to the class of Actinopterygii, the ray-finned fishes, to the order of Scorpaeniformes and to the family of the Sebastidae.

It is assumed that the name of the genus comes from the Greek “helikos” = spiral and “lenos” = cavity, with reference to the huge pectoral fins, which the fish spins spirally in order to walk over the sea bottom and are hollow for a half, that is, not having the membrane usually existing between the rays. The name of the species comes from the Greek “dactyl” = fingers and “pteron” = wing, the same etymology and meaning of the known genus Dactylopterus.

Zoogeography

Besides the Mediterranean, the blackbelly rosefish has a very vast distribution. In fact, it colonizes the two Atlantic coasts, from Canada to Venezuela and from Iceland to South Africa, including the Azores, the Cary, Madeira and Cape Verde Islands.

Ecology-Habitat

It is at home at enormous depths on sandy and compact bottoms of the continental shelf, from 50 to 1.100 m, but, at times, it comes up and one blackbelly rosefish has been found in only 20 m of water.

Morpho-physiology

It reaches the 47 cm, but the fished specimens usually measure 25-30 cm. The ehad is stocky, covered by spines over the eyes, on the operculum and the pre-operculum. The mouth, huge, has a monstrous opening almost reaching the eye. Inside stand 4-5 rows of needle-like teeth on the jaw and 3-4 on the mandible, not to talk about those of the vomer and of the palatine ones. The eye, enormous, is perfectly suitable for the great depths.

The dorsal is unique, with 12 spiny rays and 12 soft; the anal has 3 spines and soft rays; the ventral ones have one spine and 5 unarmed; but the novelty stands in the pectoral fins, vey ample, which on top do have 2 simple rays, then 9 ramified at the apex and 8 thick, for staying on the bottom, free at the extremity.

The dominant colour is the reddish-brown. On the pink sides stand out some typical dark bands. The belly is white and the mouth, inside, is black-bluish.
Like other scorpionfishes, the spines are connected to venom glands and the stings are much painful.

Ethology-Reproductive Biology

The blackbelly rosefish is a predator. It nourishes, greedily, of fishes, cephalopods, crustaceans and echinoderms.

The fecundation is internal. The matings take place even before, but the development of the oöcytes begins in December inside the body of the mother. The larvae, already partially developed, are laid on the bottom, protected by a gelatinous mass. When this dissolves, they become planktonic.

The blackbelly rosefish is caught in big quantities with the trawl nets. If able to escape the dangers, its lifespan is of 43 years. The vulnerability index of this species is of 53 over 100.

Synonyms

Helicolenus imperialis Cuvier, 1829; Helicolenus maculatus Cuvier, 1829; Helicolenus maderensis Goode & Bean, 1896; Helicolenus thelmae Fowler, 1937; Scorpaena dactyloptera Delaroche, 1809; Sebastes dactylopterus Delaroche, 1809; Sebastes imperialis Cuvier, 1829; Sebastes maculatus  Cuvier, 1829.

 

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