Spondyliosoma Cantharus

– Black Seabream –

The black seabream (Spondyliosoma cantharus) is a species of Sparidae fishes. They are recognisable by their oval compressed body and jaws containing 4-6 rows of slender teeth which are larger at the front. They are silvery in colour with blue and pink tinges and broken longitudinal gold lines. They can reach a maximum size of 60 cm in length. They live in northern Europe and in the Mediterranean, usually found on the inshore shelf at depths varying from 5 to 300 m. They are usually found in schools feeding on seaweeds and invertebrates. They breed in February to May leaving eggs in the demersal zone..

Description

The gray sea bream is a fish 30 to 40 cm in length (60 cm maximum for 1.2 kg), oval in shape. The body is compressed laterally and dorso-ventrally symmetrical, that is to say, the back is as rounded as the belly . The general coloration is silver-gray , lighter on the belly and with discontinuous longitudinal lines, more or less marked . Gray sea bream, like all Sparids, have a single dorsal fin running almost the entire length of their body and a powerful tail.

In females , the longitudinal lines are yellowish .
The males have a slightly concave forehead just above the eyes , and very curved, and a darker color. During the breeding season, they present a different livery for the populations of the Atlantic and those of the Mediterranean. In the Atlantic , males are very dark, with one or more vertical white bars on the flanks . In the Mediterranean, they are bluish , with fine blue longitudinal lines and some broad dark vertical bands.starting from the dorsal fin and fading down towards the belly. There is also a dark area behind the eye while the cheeks remain light.
During the night, the body of the gray sea bream is covered with 5 very wide dark vertical bands .

Juveniles resemble those of Diplodus annnularis when they are very young (less than 1 month); they differ from it by the old gold color while in D. annularis they are more lemon yellow. As they grow (approx. 2-7 months), the canthares retain their characteristic old gold color. Then, they take on a more silvery color like adults. On the other hand at night, brown appears, with more dark bands than in adults.

In young individuals, the tips of the caudal fin are white and the muzzle is more pointed .

Biotope

Juveniles (15-20 cm, i.e. less than 6 months) are found at shallow depth (5-30 m) near rocky bottoms or Posidonia meadows, while older individuals prefer deeper sandy bottoms which can range up to 300 m. The adults get closer to the coast in summer, especially on wrecks.

Similar Species

Young individuals can be confused with young of other species of Sparidae, such as sea ​​bream , sars, pageots, denti , etc. The longitudinal lines make it possible to differentiate the gray sea bream from these other species.

Alimentation

Spondyliosama cantharus is a carnivorous predator. It feeds mainly on invertebrates: polychaete annelids, crustaceans (especially amphipods), brittle stars, hydrozoans, as well as young cuttlefish. Consumption of seaweed has also been reported.

Reproduction

Individuals are hermaphrodites * protogynous *. The sexual maturation of females is reached between 2 and 4 years, that is to say for a size of 20 cm. There is then a gradual transformation into a male, which ends around 7-8 years old, or about 35 cm. The spawning period lasts from February to April, with variations depending on the geographical areas.
The adults most often live in schools in deep water. In early spring, the males separate and dig a nest 30 cm to 1 m in diameter in the sand, which they fiercely defend. They attract schools of females which can each deposit 40,000 to 110,000 adhesive eggs. After fertilization, the males tend to the eggs, cleaning the nest and airing them until they hatch, about 9 days later. The juveniles stay in the nest for a few weeks.

Associated LIfe

The external parasitic crustaceans Ceratothoa oestroides and especially Anilocra physodes have been reported from Spondyliosoma cantharus . Some internal parasites have also been described, notably the digene flatworms Arnola microcirrus and Monorchis monorchis .

Various Biology

Sea bream can live up to 20 years.
The jaw has 4-6 rows of conical incisors, but the molars are absent.
Dorsal fin with 11 spines and 11-13 soft rays. Anal fin with 3 spines and 9-11 soft rays.

Further information

Due to the very strong variation in livery between Atlantic males and Mediterranean males, some authors wonder if the two populations could not constitute subspecies. However, recent studies give contradictory results.
Gray sea bream is edible like most Sparidae, although less popular. It is fished mainly in the English Channel, by trawl. Annual production is 1,800 to 2,600 t (IFREMER 2004 data). After a population collapse in the early 1980s, it took around ten years for the stock to recover.
In other areas where Spondyliosoma cantharus is present , this species is not fished specifically. It is captured with other species.
It is found on the fishmongers’ stall under the name gray sea bream, which can mislead consumers who might think they are buying sea bream ( Sparus aurata ) at a more affordable price.