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.
Governance systems play an important part in ensuring environmental sustainability, and whilst these have evolved rapidly with the growth of the industry, there are differences between regions and countries. Poor governance can result in industry stagnation, the spread of preventable diseases, environmental damage and opposition to aquaculture activities by local communities and groups such as non-governmental organisations (NGOs). Key governance responsibilities are ensuring environmental assessment and decision making processes are in place for sensitive and coastal ecosystems, which help deliver sustainable aquaculture whilst managing possible adverse impacts. Other regulatory and governance aspects should cover aspects such as water abstraction and discharge, health monitoring, and so forth.
Four principles – accountability, effectiveness and efficiency of governments, equity, and predictability of the rule of law – are necessary for effective aquaculture governance. These principles should guide the administration, legislative and regulatory framework of aquaculture. In addition to governments, other stakeholders such as communities, non-governmental organisations (NGOs) and producers should also be involved in the governance of the industry1.
Sea bream farming is largely undertaken in European countries (EU) or in the European Economic Area (EEA) in the Mediterranean, where governance systems are in place to support aquaculture development2. EU/EEA regulations require all aquaculture production businesses to be registered with the authorities. There are also a range of important environmental regulations that sea bass producers need to adhere to, to minimise the potential adverse impacts aquaculture may pose to the environment. These typically regulate site location (planning), the use of chemicals and veterinary medicines, release of nutrients, escapes of farmed animals and other key environmental issues. Disease risks are also tightly regulated in producer countries with inspection schemes to confirm farms are free of serious (i.e. notifiable) diseases.
Production of Gilthead sea bream has grown strongly in the last decade and represents a successful aquaculture industry. Production in cages has increased, but the on-going consequences of the global financial crisis of 2007–2009, and the Eurozone debt crisis from the end of 2009 have to some extent limited growth of the sector, particularly in Greece. However, in Turkey growth has been less constrained by economic factors and has seen substantial increases in sea bream production.
Farmed sea bream from the Mediterranean is mostly for export, mainly to mainland Europe, particularly Italy and Spain. Greece exports around 70% of its domestic production, and exports have expanded into new markets, such as the UK, Germany and France. Trade in sea bream seed includes not only the largest producer countries, but countries such Italy, Spain and France which help supply grow-out farms across the Mediterranean.
As sea bream aquaculture grew between 1990 and 2002, production costs were driven down and product saturated the market. Prices subsequently declined rapidly by more than two-thirds; this can be attributed to the limited demand from smaller, more traditional markets for sea bream (mainly in southern Europe), the lack of diversified products, and limited focus on market development and promotion at the time. However, the drop in price subsequently opened up new markets and helped expand existing ones.
Acceptable profit margins for sea bream producers can only be sustained through further improvements in productivity and product diversification. In recent years sector has found new market opportunities which show increasing trends in sea bream consumption (e.g. Russia and the US).
Greek and Turkish sea bream (and sea bass) production are likely to continue to dominate Mediterranean aquaculture for the foreseeable future2. The outlook for the farmed sea bass sector in 2017 was cautiously positive3, so long as prices are maintained at economically sustainable levels, but this is dependent on the rate of production volume growth and the progress made towards farm cost reductions, as well as market demand.
The Aquaculture Stewardship Council (ASC) has recently (September 2018) launched a specific standard which incorporates sea bass, sea bream and meagre4.
Appropriate siting, design and construction of sea bream cage farms is essential to limit adverse impacts on the environment and natural ecosystems. In addition, if floating net-pens are located within navigable water bodies, consideration should be given to ensure that they do not impinge and restrict movement of boats, aquatic animals and the water itself. There may also be concerns over the visual impact of siting cages in the areas of natural beauty, in such areas, it is important that the design, construction and colour of farm facilities are sympathetic with the landscape in which they sit.
As sea bream net-pens are often located in areas with relatively rich wildlife, species that prey on fish can be attracted to them. This can potentially become a significant problem for a farmer due to direct losses and the stress and injuries caused to their stock. In the worst case scenario there could be significant losses to stock and/or escapes if predators breach net-pens. Birds may predate upon sea bream in ponds, lagoons and sea cages but predation by marine mammals on sea bream is not documented1.
National and local laws should be adhered to and all farms should have the required licences, permits and registrations in regards to their site and its operations, with documentation being kept to evidence compliance. Where aquaculture development plans exist, then new farms should be located within the appropriately identified areas2. Marine cage culture has ‘minimal’ impacts to the environment where farms are appropriately sited and properly managed3.
Major sea producing countries are increasingly using marine spatial planning to regulate where aquaculture can take place. Measures being taken include but are not limited to the creation of zones where production is controlled; specifying allowable production densities and minimum depths that net-pens can be sited. Both Greece and Turkey have enacted regulations in regards to marine spatial planning and the sustainable development of aquaculture4, 5. The EU has also published guidance on how aquaculture operations can be sited in protected areas (e.g. Natura 2000 sites)6.
To improve access to space and water for farming areas, the General Fisheries Commission for the Mediterranean (GFCM)7 adopted a specific resolution on Allocated Zones for Aquaculture (AZA) in 20128, 9, 10. The GFCM is a regional fisheries management organization involved in conservation, sustainable marine resources and the development of aquaculture. Many countries in Europe and in the GFCM are taking up the AZA resolution and adapting this within their national legislations. The GFCM is also preparing a ‘Strategy for the sustainable development of Mediterranean and Black Sea aquaculture’ following the AZA framework11.
Sea bream farmers should ensure all possible management measures are taken to protect stocks from predators. Deterrents, scarers and increased on-site activity may be effective. Lethal methods of predator control should only be resorted to when appropriate licences are in place and the predatory species are not threatened in any way.
Certification of sea bream farms ensures they are addressing issues such as, but not limited to, location and siting, and impacts on endangered species.
Feed is a major component of the cost of farmed sea bream production and the efficient use of feed is an important aspect of farm management; it is vital to ensure that as much of the feed as possible is consumed by the fish and that as little as possible is wasted. Efficient monitoring and management of feed regimes minimises nutrient discharges from sea bream net-pen farming and reduces the potential of pollution arising from uneaten food entering the marine environment. This is important as the accumulation of uneaten food and faecal matter beneath net-pens has the potential to affect aquatic life through de-oxygenation and algal blooms which can be associated with nutrient increase1. The key nutrients likely to cause problems for receiving waters are nitrogen and phosphorus.
In addition to controlling the amount of feed dispensed to the fish, sea bream diets have improved to make them more digestible2. This results in greater food absorption, less faecal production, and computer controlled demand feeding systems result in less food use and wastage. To improve performance, farms should monitor feed efficiency, effluents and water quality in the receiving water body.
Licensing and farm management can ensure facilities are located in areas where the environmental impact through release of nutrients is going to be minimal. Full environmental impact assessments are undertaken which include modelling impacts of the release of nutrients before licenses are issued. As technology has developed sea bass net-pens have been able to locate to more exposed locations with stronger currents and in deeper water which ensures waste materials are more widely dispersed.
Computer modelling is often used as a guide to determine licensed discharge quantities of organic waste (and chemicals) arising from marine fish-farm operations. It is typically a requirement of net pen operators that before they can obtain a site license they model the effects of potential discharges released from the aquaculture site, using methods such as MEROMOD3.
Modelling and monitoring methods are mandated by regulations and certification standards and records documented by farms. Farms should also document and record how they dispose of any other solid wastes such as fish mortalities. There have been attempts to mitigate the release of nutrients into the marine environment by growing shellfish or algae (seaweed) species in proximity to cages (i.e. integrated multi-trophic aquaculture or IMTA) which can utilise the dissolved nutrients and provide additional crops4, 5.
Enclosed hatcheries and land-based farms (recirculating aquaculture systems or RAS) can mitigate nutrient pollution risks by removing solids prior to the discharge of effluents and remove dissolved nutrients by establishing areas of reed beds or salt marshes around discharge points.
Fish Meal and Fish Oil
Marine ingredients such as Fishmeal (FM) and Fish Oil (FO) provide nutrients that often cannot be found in other feed materials (e.g. particular amino acids, vitamins and minerals), and they are essential constituents of many aquafeeds. FM and FO are a finite resource and are seen by the aquaculture industry as a strategic ingredient to be used efficiently and replaced where possible1.
Globally the FM and FO used in aquafeeds is increasingly derived from fishery and aquaculture processing by-product; the utilisation of these by-products as a raw material for FM and FO production is in the region of 25%-35% and this trend will continue; it is expected to rise to 49% by 20221, 2, 3.
IFFO The Marine Ingredients Organisation4 (formerly known as The International Fishmeal and Fish Oil Organisation or IFFO) estimate that if aquaculture is taken as a whole, producing one tonne of fed farmed fish (excluding filter feeding species) now takes 0.22 tonnes of whole wild fish. This essentially means that for every 0.22 kg of whole wild fish used in FM production, a kilo of farmed fish is produced; in other words, for every 1 kg of wild fish used 4.5 kg of farmed fish is produced5.
Perhaps the most important mitigation measure is to ensure that products such as FM and FO used to manufacture aquafeed come from legal, reported and regulated fisheries. Such fishery products can demonstrate their sourcing adheres to the United Nation Food and Agriculture Organisation (UN FAO) “Code of Conduct for Responsible Fisheries”6, known as CCRF, through several mechanisms:
Currently around 1.9 million tonnes of FM production is certified as either IFFO RS or MSC – representing about 40% of global production; most of this comes from South America, but Europe and North America are providing significant volumes, and North Africa currently has certified production. Currently there is no certified FM product produced in China and only very small quantities (less than 10,000 tonnes) are produced in the rest of Asia (and this is from by-products)2.
Aquaculture certification schemes also require that fish products used in feeds are not on the International Union for Conservation of Nature (IUCN) red lists11 of threatened species or the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)12 lists of endangered species.
GM Feed Ingredients
The use of genetically modified (GM) vegetable ingredients in animal feedstuffs (including aquafeed) is an ongoing area of debate13. Whilst some contend that GM soy can help support current levels of aquaculture, global attitudes and consumer perceptions about the use of Genetically Modified Organisms (GMOs) vary in different parts of the world, with North American markets being far less averse than European ones. However, their use in all livestock feed is widespread, and in the EU food from animals fed on authorised GM crops is considered to be as safe as food from animals fed on non-GM crops14.
Sea bream Feed
Careful management of food and feeding regimes are important to the success of aquaculture. To reduce wasting aquafeed on farms, efficient feed use can be monitored and should comply with levels set in certification standards. The indicators used can include the Feed Conversion Rate or FCR (the amount of feed an animal requires to gain a kilogram of body weight), economic feed conversion ratio (eFCR), maximum fish feed equivalence ratio (FFER), or protein efficiency ratio (PER).
Sea bream have a requirement for a high protein diet and whilst their aquafeeds are still relatively high in FM and FO, vegetable materials are increasingly substituting these marine ingredients.
Sea bream feeds now contain approximately 15-20% FM and 2-5% FO15. Over the last 10 years or more the inclusion of marine ingredients in sea bream feeds has declined, and this is a trend set to continue. In terms of feeding efficiency, the average FCR figure for sea bream is around 216. IFFO The Marine Ingredients Organisation estimate that in 2015 for every 0.53 kg of whole wild fish used in FM production for all marine fish (which includes sea bream) aquafeeds, a kilo of farmed marine fish are produced5.
As feed companies constantly develop their aquafeed formulations the decreasing inclusion of marine ingredients will not only continue in sea bream feeds but in those for a number of other aquaculture species.
In common with all other animal farming systems in which animals are raised in greater numbers than they would be found in nature, the farming of sea bream can potentially increase the risk of disease outbreaks due to the number of individual animals living in close proximity to each other. It is essential that good husbandry and a pro-active approach to health management is adopted at each farm location in order to minimise and mitigate these risks.
Sea bream can be affected by a range of viral and bacterial pathogens, the most important of which cause viral lymphocystis disease virus (LCDV), the bacterial diseases vibriosis and photobacteriosis/pasteurellosis. Sea bream can also be affected by parasites such as Sparicotyle chrysophrii, Amyloodinium occelatum and Cryptocaryon irritans1, 2. The effects of disease can have major economic impacts on the industry.
The first line of defence in disease and pathogen management is effective biosecurity and health plans to minimise disease and its spread3. The key elements of biosecurity include: practical and appropriate legislative controls; adequate diagnostic and detection methods for infectious diseases; disinfection and pathogen eradication methods; reliable high quality sources of stock; and best management practices3, 4. The development of a written health plan updated annually and approved by an aquatic animal health specialist is recommended and often part of EU regulations5 and certification requirements6.
The farmer should follow the instructions of aquatic animal health specialists about who to inform and how to stop the spread of the disease. Regular health checks and screening allows for rapid action to be taken if problems begin to develop. Certification schemes set targets for maximum average real percentage mortality rates. Maintenance of good daily records of mortalities facilitates management by highlighting when in the production cycle disease problems are likely to occur.
When needed, there are a range of medicines, chemical treatments and vaccines available to control sea bream disease and pathogens, including antibiotics. Overuse of antibiotics in farming or for human medical treatment speeds up the development of antibiotic resistance, which is when bacteria change and become resistant to the antibiotics used to treat them7. In Europe, medicines and chemicals used during the farming of fish destined for human consumption are tightly regulated to minimise impacts to the target animal, consumer and environment5.
Vaccination also plays an important role sea bream aquaculture, and there has been significant development of sea bream vaccines and their application in recent years8. Increase research in to sea bream vaccination has been called for by the industry.
Sea bream farms should only use veterinary medicines and chemicals that are approved by national authorities and these should be prescribed by an aquatic animal health specialist. Veterinary medicines that should not be used:
Good husbandry and strict adherence to the principles of biosecurity are also important aspect of managing the movement of eggs and live fish between sites, including in some cases internationally, where there is an opportunity to spread pathogens between locations.
Functional aquafeeds include a range of additives used to improve growth and feed utilisation, but also to support the health and stress resistance. Additives, such as probiotics, prebiotics, phytogenics, and immune-stimulants may help improve sea bream disease resistance10, 11.
These prohibitions are frequently part of regulation and specified in certification programmes.
Escapees from aquaculture facilities can potentially impact on habitats and species in the receiving water bodies. Problems could occur due to competition, potential disease transfer, establishment of non-native species, interbreeding with wild populations, and impacts on sensitive habitats.
With any open water containment system there is the potential for stock to escape. Whilst establishing contingency plans in case of sea bream escapes is essential1, prevention is the key to mitigating escapes. Escapes from farms occur both through repeated low-number incidents and through large-scale events. Technical and operational failures can lead to escapes: cages can be breached in storms; holes can appear through wear and tear; predator interaction and operational accidents can occur, and so on. Losses due to escapes represent a considerable financial loss to a farm, so it is in its interest to prevent them.
Increased production has led to an increase in escape incidents from Mediterranean farms2, and there is evidence of interbreeding of escaped sea bream with wild stocks, potentially weakening their genetics3. Advances in sea bream genetic research and the enhancement of farmed strains via breeding programmes has been on a lesser scale than in other farmed fish (such as salmon); consequentially farmed sea bream are not too distinct genetically from wild populations. However, as more attention is focused on breeding to improve productivity the issue of sea bream escapes may well become of increasing concern.
It may be possible that technologies become available to produce sterile populations of sea bream that are unable to reproduce if they escape. However, in the absence of this technology broodstock should ideally originate from local endemic or naturalised sea bream populations to minimise the potential impacts of cross breeding.
Recapturing fish after escape (at or close to the point of escape) is a logical management option, however evidence suggests that fish tend to disperse rapidly from the point of release and recapture efforts are often delayed after large-scale escape events, which typically occur during storms. These two factors mean that few attempts to recapture sea bream after large-scale escape incidents have been successful4.
Improved netting materials, enhanced engineering standards and equipment build quality, better staff training around vessel handling and use, and efforts to deter predators all reduce escape incidents, whilst the biosecurity of land-based sea bream RAS facilities means that escape risks are minimal within these systems.
Aquaculture (and fisheries) certification and labelling programmes have become a primary tool to address sustainability issues of farmed seafood, and the development of third party assessment and certification has provided new forms of governance traditionally dominated by state-based regulation1, 2. The growth in the number of certification schemes has led to confusion surrounding the myriad of them out there. To try and combat this, the Global Sustainable Seafood Initiative (GSSI)1 has developed its global benchmarking tool to measure and compare certification schemes and standards performance across seafood production.
Given the prominence of environmental issues as the driver for the development of aquaculture standards, there is an understandably strong emphasis on environmental criteria within them3. Certification enables aquaculture producers to voluntarily demonstrate their responsible farming practices by: complying with national legislation; minimising impact on habitats and wildlife; making the best use of locally available resources; and ensuring the best use of feed and therapeutic products.
Aquaculture certification currently has moderate to high coverage of labour standards (e.g. minimum wage)3, however, increased social and economic requirements related to human rights, gender and sustainable livelihoods are being developed.
Since 2011, a partnership of UK businesses called the Sustainable Seafood Coalition (SSC)4 have been working to ensure all fish and seafood sold in the UK comes from sustainable sources, and aquaculture certification plays a pivotal role. All members need to ensure that the aquaculture source (considering feed mills, hatcheries, and farm sites) is certified under a third party standard, or audited to a members own good aquaculture standard or code of practice5.
The table below looks at some of the major aquaculture certification schemes, including those for sea bream, and if they address the Key Considerations highlighted throughout the profiles. It also highlights which scheme has a standard/s successfully benchmarked by the Global Sustainable Seafood Initiative (GSSI)1.
Read more on aquaculture certification, including that of sea bream, after the table.
|Certification Scheme: Description and Links||Governance||Farm Siting||Nutrient Pollution||Feed||Disease, Medicines & Chemicals||Escapes & Introductions||Wild Seed||GSSI Benchmarked|
Founded in 2010 by WWF and IDH (Dutch Sustainable Trade Initiative) the ASC is an independent not for profit organisation with global influence. ASC aims to be the world’s leading certification and labelling programme for responsibly farmed seafood.
The ASC consumer label demonstrates the integrity of the seafood product.
GAA BAP has been certifying aquaculture since 2004, and is administered by the GAA, a nonprofit organization dedicated to advocacy, education and leadership in responsible aquaculture. Aquaculture Facility Certification:
The BAP program employs a star system to signify the integration levels of BAP certification along the aquaculture production chain. These stars are displayed on the BAP logo and appear on packaging for a variety of farmed seafood products worldwide.
GG offers 16 standards for 3 scopes: Crops, Livestock, and Aquaculture. GG has been one of the most widely accepted private sector food safety certification in the world since 2007.
GG Aquaculture certified producers have now the option to use the consumer facing GGN Certified Aquaculture label.
Friend of the Sea (FoS)
FoS is a non-profit NGO, whose mission is the conservation of the marine habitat. FoS is now a leading international certification project for products originated from both sustainable fisheries and aquaculture:
FoS and GG have consolidated a partnership agreement to add the FoS logo on consumer products.
All aquaculture products sold as “organic” in the European Union (EU) have to fulfil the requirements that are laid down by the EU regulations:
This includes products certified according to private organic standards. The EU Organic logo makes organic products easily identifiable by consumers.
Naturland was founded in 1982 when organic agriculture was regarded as a marginal issue. Since the mid-1990s, Naturland has developed standards for different species and production systems in aquaculture:
The Naturland label is intended as a guide for consumers.
The Soil Association was formed in 1946 and champions organic principles and practice.
The Soil Association logo sends a message to consumers that the product is organically produced.
• – Indicates the Certification Scheme addresses the Key Consideration
✔ – Indicates the Certification Scheme has had one or more of its Standards benchmarked against the Global Benchmark Tool Version 1 and recognised by the GSSI Steering Board
Certified Aquaculture Production
Production of certified seafood, both aquaculture and wild catch, has grown rapidly over the past decade and now represents a significant portion of global seafood production. Certified sustainable seafood in 2003 equated to some 500,000 tonnes (0.5% of global production); in 2015 this figure had risen to 23 million tonnes (14% of global production). Some 80% of certified seafood is wild catch, but certified aquaculture is growing twice as fast and is set to dominate growth in certified seafood for the foreseeable future3.
In 2015, certified aquaculture accounted for 6.3% of world aquaculture production. Of this 6.3%, seven species groups were dominant (i.e. salmon, pangasius, mussels, tilapia, prawns, trout and sea bream) and accounted for 97%3. This relatively low global level of certified aquaculture and the narrow range of species groups, is largely due to:
Certification of small-scale aquaculture continues to be an issue, mainly due to the cost and difficulties in complying with standards; key challenges include finance, technical knowledge and organisational capacity. Educating small-scale farmers on how to comply, as well as identifying national policy and regulatory gaps supporting small-scale aquaculture certification, is becoming ever more necessary6. Multiple-farm or ‘cluster’ certification may be a way forward for small-scale producers.
Four schemes are responsible for the majority of certified aquaculture production, namely the Aquaculture Stewardship Council (ASC), Global Aquaculture Alliance Best Aquaculture Practice (GAA BAP), GlobalG.A.P. (GG), and Friend of the Sea (FoS)3.
Certified Sea bream Production
Figures provided by the certification schemes themselves and relating to their totals of certified farmed sea bream break down into:
(It is important to note that certification under one scheme does not preclude certification under another, and gathering accurate data on rates of multiple certification is very difficult. As a result simply adding the production volumes of individual schemes can result in double counting and overestimation. The authors of the aggregate data referred to above make no adjustment for multiple certification.)