Bass, seabass (Farmed)

Dicentrarchus labrax

Method of production — Farmed
Production country — Europe
Production method — Open net pen
Certification — Aquaculture Stewardship Council (ASC) certification
Picture of Bass, seabass (Farmed)

Sustainability rating three info

Sustainability overview

Updated: November 2019.

European union and Turkey are primary producers of farmed seabass. Seabass are generally farmed in open sea pens and are fed a diet reliant on wild fish capture as a key ingredient. Seabass farmed in this way can cause some environmental concerns, including escaped farmed fish and the data surrounding escapes; interactions between escaped and wild fish; use of chemicals, in particular antibiotics and farm level data relating to their use and some remaining concerns surrounding enforcement and regulatory controls. Seabass are carnivorous fish that require more fish in their diet than farming them actually produces, leading to a net loss of marine proteins and oils. The fish used to produce their feed cannot be assured to be sourced from a sustainable supply. ASC, GAA BAP 3* & 4* and GLOBALG.A.P certified seabass addresses some of these problems.

This rating is based on full compliance with certification requirements. Commercial buyers should therefore ensure that full compliance has been achieved in order for this rating to be applicable.

Feed Resources

Criterion score: -3 info

The Aquaculture Stewardship Council (ASC) standard for feed is under development and in 2016, it published an interim solution for the ASC Marine Feed Ingredients. Under the ASC Standard, non-marine ingredients do not need to be from sources certified by an ISEAL Member’s certification until 2023. The majority of aquaculture feeds used by EU and Turkish producers of European seabass, gilthead seabream and meagre are produced by suppliers that have a responsible feed sourcing policy, however the implementation of this cannot be verified in these countries. The majority of terrestrial inputs used in the formulation of these diets is traceable to the country of origin, however the responsible sourcing of these cannot be assured at this time. The Feed Fish Dependency Ratio for this species currently indicates that more fish protein is required in the diet than these fish produce, making them a net consumer of fish rather than a net producer.

Environmental Impacts

Criterion score: 2 info

The requirements of the Aquaculture Stewardship Council (ASC) standard do much to mitigate against environmental impacts of production via specific, audited criteria. The production cycle of farmed European seabass, gilthead seabream and meagre, including the hatchery phase takes place in full strength seawater. In the ASC standard, only fingerlings that are produced in hatcheries may be used for grow-out purposes. Farms in the EU and Turkey use mooring techniques which cause minimal alteration to the seabed. Marine net pen culture systems inevitably discharge fish wastes directly into the aquatic environment. The ASC standard has indicators to ensure all biological and non-biological waste produced by a farm is recycled, reused or disposed of properly and does not affect neighbouring communities. There is a potential problem with parasites and pathogenic disease outbreak but these do not appear to present any population-level threats to wild species in the region. The impact on wild species is limited by effective management and a Fish Health Management Plan (FHMP) is in place. Chemicals are used but the environmental impact of chemical use is effectively regulated by the ASC standard. Open net pens are vulnerable to large escape events, as well as frequent trickle losses. The ASC Standard seeks to address farmed fish escapes by demanding a rigorous farm management system to minimise risk of escapes. Lethal control of predators is only used where worker safety is at immediate risk.

Fish Health and Welfare

Criterion score: -1 info

The ASC standard does not cover animal welfare and humane slaughter. The slaughter method predominantly employed by European seabass, gilthead seabream and meagre farms is to kill fish by immersion in an icy slurry at the time of harvest. In 2009, the European Food Safety Authority recommended that electrical stunning be urgently adopted as a more humane industry practice. Despite this advice, which has since been echoed by other welfare organisations, humane slaughter requirements still remain absent in legislation governing this sector


Criterion score: 5 info

Policy makers across the geographic scope of this assessment have made considerable progress toward an effective inter-regional governance strategy for the aquaculture sector over the last few decades; this has been a formidable task, given that a total of 21 countries border the Mediterranean. The Aquaculture Stewardship Council (ASC) standard criteria addresses all issues that you would expect to be covered by good country legislation, and these are deemed to be effective due to the independent audit carried out to confirm compliance. None of the assessment questions addressing environmental impacts have been scored negatively due to poor regulation.

The ASC standards cover the main environmental and social impacts of aquaculture, including fish health, feed and fair employment conditions, by setting metric-based indicators. Farms are assessed annually by external auditors and results published. ASC products are traceable throughout the supply chain. ASC is the only ISEAL compliant aquaculture certification scheme.

Production method

Open net pen

Seabass are farmed in open net pens allows which allows for interaction with the surrounding environment and therefore has to be managed in such a way as to minimise negative environmental and ecological impacts.


Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below. Click on a name to show the sustainable options available.

Basa, Tra, Catfish or Vietnamese River Cobbler
Cod, Atlantic Cod
Cod, Pacific Cod
Coley, Saithe
Hake, European
Monkfish, Anglerfish, White
Pollock, Alaska, Walleye
Spurdog, Spiny Dogfish, Dogfish, Rock Salmon or Flake
Sturgeon (Farmed)


Bass or seabass belongs to a family of spiny-finned fish called Moronidae, which are closely related to groupers. Bass breed from March to mid-June, mostly in April, in British coastal and offshore waters. From January to March in the Bay of Biscay and from February to May in the English Channel and eastern Celtic Sea. It is a long-lived and slow growing species - up to 30 years of age, and can achieve a length of up to 1m with a weight of 12kg. Male bass mature at 31-35cm (aged 3-6 years) and females mature at 40-45cm (aged 5-8 years). Once mature, bass may migrate within UK coastal waters and occasionally further offshore. Increases in sea water temperature in recent decades has likely led to a more northerly distribution of seabass as it is now found further north into the North Sea. Climate warming may also have lengthened the time adult seabass spend in the summer feeding areas. After spawning, seabass tend to return to the same coastal sites each year.


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