Every gilt-head bream starts life male, and some later become female
The gilt-head bream, a Mediterranean favourite on restaurant menus, matures as a male by age two. Later, some individuals grow ovaries and lose their testes. Today far more of these fish come from farms than from the sea, with Turkey and Greece leading world production.
Sparus aurata belongs to the seabream family and is the only living member of its genus; a fossil relative lived in the Paratethys Sea of central and eastern Europe during the Middle Miocene. Carl Linnaeus described it in 1758. The genus name comes from an ancient Greek word for the fish, and aurata, meaning gold, refers to the golden bar across the head between the eyes. Besides that bar it has a blue-grey back, silvery flanks, a dark spot behind the eye and a red edge to the gill cover.
It ranges from Britain and Ireland south possibly to Senegal, including the Canary Islands, throughout the Mediterranean and into the southern and western Black Sea; those around Madeira are farm escapees. It lives over sand and in seagrass meadows between 1 and 150 metres down, the young staying shallower than 30 metres, and tolerates brackish water. Its jaws carry four to six pointed front teeth backed by rows of blunt, rounded ones, well suited to its main diet of shellfish, though it eats some plants too. Most adults are about 35 centimetres long, with a maximum of 70 centimetres and a published record weight of 17.2 kilograms.
Biologists call its sex change protandrous sequential hermaphroditism. When the species' genome was published in 2018, researchers found that genes active mainly in ovaries were evolving unusually fast, probably linked to this unusual reproductive pattern.
Wild catches are modest, between 6,100 and 9,600 tonnes a year during 2000 to 2009, mostly in the Mediterranean. Traditional farming in coastal lagoons and salt ponds gave way in the 1980s to intensive rearing systems, and output rose from almost nothing in the late 1980s to 140,000 tonnes in 2010, far outstripping the wild fishery.
Source: Gilt-head bream
