The gilthead seabream, Sparus aurata (Linnaeus, 1758) is a perciform fish, belonging to the family Sparidae and to the genus Sparus.

(Alyanak, Sea Bream, Gilthead Sea Bream, Goldbrasse)

Position on Systematics (Taxonomy)

Superphylum:   Metazoa

Phylum :          Animalia

Subphylum:      Vertebrata

Superclassis:    Gnathostomata

Classis:            Pisces

Subclassis:       Osteichthyes

Superordo:       Actinopterygii

Ordo:               Teleostei

Subordo:         

Family:             Sparidae

Genus:             Sparus

Species:           Sparus aurata (Linneaus,1758)

Fig. 1- Adult specimen of gilthead sea bream

Fig. 2- Adult specimen of gilthead sea bream

Family Description

Family Sparidae

Percoid fish with body oblong, usually deep and compressed. Scales cycloid or weakly ctenoid. Head large, often with a steep upper profile. Snout and supraorbital area scaleless. Mouth small, with the upper jaw reaching no further than the middle part of the eye. Preoperculum scaled, without spines on margin. Jaw teeth usually differentiated into conical, incisor or canine teeth in front and molar-like teeth behind. Palatines bones usually toothless.

One single unnotched dorsal fin with 10 to 15 stout spines and 9 to 17 rays. The spiny anterior part has the same length of the posterior part with rays. Anal fins with 3 stout spines and 7 to 16 rays; pectoral fins usually long and pointed; ventral fins with axillary scales; caudal fin emarginate or forked. A single continuous lateral line. Colours vary greatly, from silver to reddish to almost black.

Almost all Sparidae are demersal, and are found in relatively shallow waters, often in rocky areas; the young fish generally live in shallower waters than the adults; fry and fingerling school together, while adults usually show a solitary behaviour.

The eggs are pelagic, spherical (with a diameter of around 1 mm) and have an oil drop.

Many sparids are hermaphroditic: when reaching sexual maturity there could be a majority of males (protandric hermaphroditism) or of females (protogynic hermaphroditism). Sparids are carnivorous fish and feed mainly on molluscs and other benthic organisms, which they break with their strong teeth.

Due to their excellent meat, many representatives of this family have a high commercial value. Sparids are divided amongst many genera and a large number of species living in all tropical and temperate seas, including exceptionally cold and brackish waters. In the Mediterranean eleven genera represent the family: Dentex, Sparus, Diplodus, Pagellus, Pagrus, Lithognatus, Spondyliosoma, Oblada, Crenidens, Boops and Sarpa.

DISTINCTIVE CHARACTERISTICS OF THE SPECIES

The genus Sparus is characterized by molariform teeth and 75-85 scales along the lateral line. Sparus aurata is its only species of this genus in the Mediterranean.

Biology

Morphology

The gilthead seabream presents a body with an oval shape, very high and laterally compressed. The head profile is convex with small eyes. The cheeks are covered with scales and the pre-opercular bone is scaleless. The mouth has the mandible shorter than the maxilla. Both jaws show canine (4-6) and molariform teeth, in 2-4 series in the upper jaw and 3-4 series, of which 1-2 are notably bigger, in the lower jaw.

The gill rakers are short, 11-13 on the first branchial arch and 7-8 on the lower part. The lateral line has 75-85 scales. The dorsal fin presents 11 hard and 13 soft rays, the anal fin 3 hard and 11-12 soft rays. The pectoral fins are long and pointed, while the ventral ones are shorter. The caudal fin has pointed lobes. All the vertebra present parapophises and sessile ribs are absent.

The gilthead seabream colour is silver-grey with a big dark spot at the beginning of the lateral line that covers also the upper part of the opercular bone. A gold and a black band is found between the eyes, the golden one always narrow in the central part. The dorsal fin is blue-grey with a median black line. The caudal fin is grey-greenish white with black tips.

Fig. 3 - Gilthead seabream, teeth and jaws

Geographic distribution

S. aurata is common in the Mediterranean Sea, it is present along the Eastern Atlantic coasts from Great Britain to Senegal, and is rare in the Black Sea. Due to its euryhaline and eurythermal habits, the species is found in both marine and brackishwater environments such as coastal lagoons and estuarine areas, in particular during the initial stages of its life cycle. Born in the sea during wintertime, the fingerlings typically migrate in early spring towards protected coastal waters in search for abundant food and milder temperatures (trophic migration). Very sensitive to low temperatures (lower lethal limit is 4°C), in late autumn they return to the open sea, where the adult fish breed.

The gilthead seabream is usually found on rocky and seaweed bottoms, but it is also frequently caught on sandy grounds. Young fish remain at low depth (up to 30 m), whereas adults can reach deeper waters (maximum depth of 150 m).

Fig. 4 - Gilthead seabream geographic distribution

Reproduction

The gilthead seabream is a protandric hermaphrodite with a breeding season ranging from October to December. The gilthead seabream is a functional male in the first two years and at sizes over 30 cm become females. After spawning, the eggs, which are spherical and transparent, have a diameter of slightly less than one mm. and present a single large oil droplet.

Fishery

The gilthead seabream is fished with traditional and sporting equipment, and sometimes with semi-professional systems (Spain, Sicily, Egypt and Cyprus), trawl nets, bottom set longlines, hand lines are also commonly used. The gilthead seabream is regularly present on the markets in Adriatic, Greece, Turkey and Maghreb. It is commercialised fresh, refrigerated and frozen.

References: FAO,2005