Gilthead Sea Bream
Sources, Quantities and Cultivation Methods
Source and Quantities
Gilthead sea bream (also known as sea bream)1 are common in the Mediterranean Sea and present along the Eastern Atlantic coasts from Great Britain into Senegal, and found in both marine and brackish water environments such as coastal lagoons and estuarine areas2.
Sea bream is an important fishery and aquaculture species. Farming sea bream was traditionally small-scale, based on the capture of wild juveniles to be reared in lagoons, but nowadays it is farmed intensively using net pens, largely in Southern European coastal waters3, 4.
Sea bream is one of the most important cultured species in the Mediterranean. World production has increased steadily5 from around 96,000 tonnes in 2003 to an estimated 185,980 tonnes in 2016 and valued at US$977 million. As shown in the map, Greece and Turkey are the biggest producers and combined represent 57.7% of world production2, 6.
Domestic Market Information7, 8
Over the past ten years (2008 to 2018) sea bream has grown in value and volume in Great British retail (i.e. in England, Scotland and Wales) by 493% and 494% respectively from a base of £2.8 million and 189 tonnes in 2008. Growth remained strong despite having an average price nearly double that of cod.
In 2018, UK retail sales of sea bream were worth £17.2 million (+0.4% compared to the previous year) with a volume of 1,175 tonnes (+4.4%), average price £14.66 per kg (-3.9%); ranking as the 19th most popular species by value in the 52 weeks to 16/06/2018 (including discounters).
In 2018, the UK imported 3,864 tonnes of sea bream, including 3,051 tonnes of chilled, and 813 tonnes of frozen.
Note: the difference between the volume of sea bream sold in UK retail and that which is imported is due to its use in the foodservice industry (e.g. restaurants) (no data available) and that which is re-exported.
Production Method2, 3, 9
Sea bream were traditionally reared in enclosed lagoons where they fed naturally until harvested. Some of these early production systems are still operational today. The example of Atlantic salmon farming in Northern Europe, combined with a scarcity of juvenile sea bream for lagoon rearing, led to research programmes being initiated in the 1960s in order to intensify production. This enabled the start of commercial scale sea bream farming in coastal areas of the Mediterranean in the 1980s.
Selective breeding programmes for sea bream are now in place. These are generally part of larger integrated companies which control the entire process from reproduction to harvest, however there are still independent European sea bream hatcheries that sell juveniles (i.e. seed) to on-growing facilities. Along with feed, the purchase of seed is the biggest operating cost for sea bream farms. A schematic of modern sea bream production is given opposite.
Broodstock are kept under controlled conditions with spawning initiated using hormonal treatments and photomanipulation (control of lighting used to prolong the sea bass spawning cycle). Fertilized eggs are collected on the surface of spawning tanks, placed in incubator tanks, and hatch after 48 hours At this point they are given specialised diets, including live feeds such as rotifera (microscopic zooplankton) and artemia (a small crustacean).
After 40-50 days, the larvae are transferred to a weaning unit where they are fed a formulated high-protein ‘micro-diet’ (small pellets). After a further three to four weeks the fry are transferred to juvenile breeding units. Two months later, at 2-5 g, they are ready for on-growing.
During on-growing fish are fed and reared in floating net-pens until harvest; this will be undertaken in either small cages in sheltered marine sites, or larger net-pens in more exposed locations. Along with feed, the purchase of seed is the biggest operating cost for sea bream farms.
Although producers rear a range of sizes for market, sea bream are generally harvested when they reach 350-400 g, which takes from a year and a half to two years, depending on water temperature3.