Why not?

  • The seabass stock in the North Sea is not looking good
  • 96% of consumed seabass comes from aquaculture

Seabass often gets a red score on the VISwijzer. In the Netherlands, a lot of seabass found in restaurants is uncertified, which makes it better to avoid it altogether. The reason being that there are problems with both farmed and wild seabass. Read more about this in our factsheet!

Why should you avoid eating seabass?

Most of the seabass (96%) we eat is farmed seabass, a lot of which is uncertified. The remaining 4% is wild seabass, which is often only found in restaurants, although even here farmed seabass is likely more common. For seabass, unfortunately, there are problems with both wild and farmed seabass making it better to avoid buying either when origin is unclear. 

Farmed seabass 

Seabass aquaculture is mostly done in the Mediterranean. Unfortunately, many farms are uncertified, which results in lacking regulation to prevent the following problems. Firstly, the feed is often made with unsustainable ingredients. Second, farming at sea pollutes the water with chemicals and faeces. There is also the risk of farmed seabass spreading disease or escaping and crossbreeding with its wild counterpart. Crossbreeding of farmed and wild seabass can cause genetic diversity to decrease, as farmed seabass are much more genetically homogenous. 

ASC certified seabass is also available and has better regulation to decrease the ecological impact of farming fish. This makes ASC certified seabass a sustainable choice, but outside of the supermarket it is difficult to find. Therefore, if certification cannot be checked, farmed seabass is best avoided.  

Wild caught seabass 

Due to warming seawater, the stock of wild seabass in the North Sea has been moving further northward in the past years, this has unpredictable consequences for a fish stock that was in a very bad state for many years in the past. Luckily since 2016 the seabass stock has not declined further, but neither has it grown to healthy levels. This is because it takes a very long time for a fish species to return to within safe biological limits. Therefore, seabass is managed with a kind of catch quota (the amount of seabass that may be caught) and is also regulated with a closed season.  

The fishing gear used to catch seabass is diverse, as seabass is often caught as bycatch in other fisheries. The quota is kept low to make targeted fishing less attractive, unfortunately, because it is an expensive fish, this makes illegal fishing more attractive. Most of the wild seabass on the market in the Netherlands is caught with unsustainable gillnets or trawler nets. Because catch method and origin are often unclear, it is best to avoid eating wild seabass. 

What certification exists in relation to seabass?

Farmed seabass 

As seabass is a popular farmed fish, ASC certification exists for this species and can be searched for in supermarkets. ASC ensures that seabass with their label has a reduced negative impact on biodiversity compared to non-ASC labelled farmed seabass and has a proper traceability procedure to back up this claim. Good Fish supports this label as a sustainable choice.  

Another certification for seabass is GLOBAL GAP. It covers the whole supply chain including processing plants. Good Fish considers GLOBAL GAP the minimum requirement for farmed fish and the level of sustainability that should be the base to gain access to Dutch supermarkets.  

Best Aquaculture Practices (BAP) is an American counterpart to ASC, created by the Global Seafood Alliance. They too cover the whole supply chain including processing plants, but ASC still beats them when it comes to traceability.   

In the supermarket you may also find seabass with a Friend of the Sea (FOS) ecolabel. Although improvements have been made to the reliability of the label, it is still not transparent enough compared to other trusted labels. Therefore, FOS is not supported by either the World Wildlife Fund or Good Fish as a reliable quality label.  

Lastly organic seabass can be found in the supermarkets. Organically farmed fish stands for a lower maximum of fish in the pens compared to conventional practices, no preventative medicines or growth hormones used, and only natural reproduction.  

Wild seabass

Fisheries on wild fish can attain Marine Stewardship Council (MSC) or Best Seafood Practices (BSP) certification. Criteria for these certifications are a healthy stock, good management and low impact on other species and the ecosystem. Seabass fisheries cannot meet all three criteria and therefore no certified wild seabass exist on the market. 

Why is seabass feed considered unsustainable?

When considering uncertified aquaculture, the fish feed is often only optimised to promote growth. Because seabass is a predatory fish, this means they need a lot of fish protein and oil in their feed to grow fast. In a standard feed this leads to a fish meal content of 56% and fish oil content of 7%, resulting in an unfavourable fish-in-fish-out ratio of 3 to 1. 

Furthermore, the source of the fish meal and oil ingredients is not checked for sustainability or social concerns. Likely coming from overfished stocks from regions such as Peru or Mauritania, instead of coming from fish cuttings or healthy fish stocks.
In a region like Mauritania there is reason to believe that the overfishing for fish meal is likely to cause hunger for the local population, as 25% of the people there already struggle with securing food.  

Certified aquaculture does not have these problems. ASC or organic certified seabass checks for responsibly sourced ingredients and sets limits to the fish-in-fish-out ratio. 

What impact does seabass aquaculture have on the environment?

The vast majority of European seabass aquaculture is carried out at sea in cages. However, an increasing number are farmed on land in tanks with recirculation systems.  

Sea cage farming relies on the natural exchange of water to remove the faeces and excess nutrients from spilled feed. In areas with a lot of aquaculture, this can lead to local eutrophication, especially directly underneath the cages, even resulting in oxygen-deficient zones. If left unchecked this damages the local ecosystem.  

Another problem with sea cages is that many fish are kept together in one cage, and as with any form of intensive farming, this makes disease outbreak more likely. Because sea cages are open systems, the chance of the disease spreading to other cages and wild seabass close by is likely. In Europe, the most common disease outbreak among seabass is Viral Nerve Necrosis (VNN), which has no vaccine or drug to combat it.
Parasites are also a problem in sea cage farming, to combat them chemicals are often used, polluting the water. 

Lastly, a problem with sea cage farming is escaping fish. Because seabass is native to Europe, any escaped farmed seabass can potentially find wild seabass and mate. However, farmed seabass are genetically very homogenous compared to wild seabass, meaning if this crossbreeding happens often the genetic diversity of wild seabass declines. This makes a wild population more vulnerable to disease and changes to the environment.  

Are antibiotics used in seabass aquaculture?

Due to the wide variety of diseases that affect seabass, antibiotics are used as treatment and a preventative measure. However, within the EU, there are regulations to stop preventative use of antibiotics. Therefore, seabass from the EU has a lower likelihood of having been exposed to anti-biotics.  

Nevertheless, many of the seabass sold in the EU are imported from countries outside of the EU, such as Turkey, the world’s largest producer of farmed seabass. As a non-EU state they do not have to follow EU regulation on the use of antibiotics. It is likely that seabass produced outside of the EU has been exposed to antibiotics, especially concerning uncertified seabass.  

Are there welfare issues with farming or catching seabass?

Currently, the vast majority of seabass, both farmed and wild caught, are killed using the inhumane method of live chilling in ice slurry or are left to asphyxiate on land. These methods are aversive, causing suffering for extended periods (minutes to hours) before consciousness is lost and is deemed an unacceptable slaughter method. Contrary to salmon and trout, the electronic stunning is not common practice, even for organic certified seabass. From a welfare point of view, it is best to avoid seabass completely. 

How much seabass is farmed?

The farming of seabass has increased exponentially since the early 1980s. Since 1992, farmed European seabass has overtaken wild catch. Nowadays 96% of the seabass consumed comes from aquaculture, due to increased demand and the decline of wild fish stocks. In 2016, the production of farmed seabass internationally reached 191,000 tonnes. Globally, Turkey is by far the largest producer of farmed seabass. In the EU, Greece, Spain, Croatia and Italy are the largest producers of seabass, in fact the Mediterranean region accounts for 94% of Europe’s farmed seabass production. 

How is European wild seabass stock doing?

European seabass saw significant depletion since the increase in seabass fisheries in the 20th century and has been fluctuating around a stable but low point from then on. This resulted in a 32% decrease of Seabass stock size across their European range.    

Northern waters 

The sea bass stock in the southern and central North Sea, Irish Sea, The Channel, Bristol Channel and the Celtic Sea has declined since around 2011. Because of that regulations were made to lower fishing pressure (F) since 2013, lowering the fishing pressure to below the maximum sustainable yield (MSY) since 2016. However, this has only resulted in limited growth of the stock, likely due to spawning stock biomass (SSB) only having recovered above the minimal safe levels (Blim) in 2021, but not yet above the levels considered under a precautionary approach (Bpa). Recruitment of seabass has also been low since 2008, another cause for the lagging growth of the stock.  

Figure 1: Spawning stock biomass (up) and Fishing mortality including recreational removal (below) in the greater North Sea region (ICES, 2021a).

Northern and Central Bay of Biscay 

In the South-western waters of the Atlantic, seabass is in better shape. SSB is not only above limit level but just above the set precautionary level as well. Moreover, fishing mortality is well below MSY. However, seabass is in a precarious position and lifting the current management measures could shift the stocks of seabass into dangerous levels again.  

Figure 2: Spawning stock biomass (up) and Fishing mortality including recreational removal (below) in the Bay of Biscay (ICES, 2021a).


In the Mediterranean, the stock is estimated to have declined by 20-30% since the 1990’s. In the Mediterranean, fish stocks are managed at national level which continues to result in overfishing. Especially because the emergency measures implemented in the other European seabass ranges didn’t concern the Mediterranean Sea. This means that the abundance of seabass continues to be low due to overfishing. On top of that there is also an increasing climatic pressure of global warming. 

In short 

ICES maintains that the European stock of seabass remains in a fragile state, only growing very slowly. It was advised by CEFAS that it could take 15 years for the stock to recover fully.  

At their worst state, European seabass stocks were looking likely to crash in the near future if emergency measures were not adopted. However, a genuine threat of extinction has only been claimed in the media and is not substantiated by data. If management measures continue to be precautionary, in the next two decades, seabass will be more sustainable to consume, but for now it is better to avoid eating wild seabass.  

What fishing techniques are used to catch wild Seabass?

Wild seabass is caught with all kinds of equipment in the (Greater) North Sea: longlines, bottom trawlers, fixed/drift nets, Danish seines and pelagic trawlers are all used (Table, 1). According to ICES, 45% of commercial landings of European Seabass is done by lines, this includes handlines and pole lines.  

 Table 1: Seabass catch methods (ICES, 2021a)

Out of the three main fishing methods for seabass, hand and pole lines can be considered sustainable. This is because they are highly selective and do not damage the seafloor. However, this method is also used a lot to illegally catch seabass, therefore one must be careful when buying “line-caught” seabass in a restaurant and its better to avoid.  

Fixed/drift nets are the 2nd most used gear. These “passive” nets can be used to trap fish. This means they are not dragged or towed by fishing vessels. These fishing techniques are normally not associated with seafloor destruction. However, the nets can be abandoned or lost leading to ghost gear where it can continue to catch fish unintentionally. Besides, passive methods tend to occasionally have bycatch of marine mammals, seabirds, sharks or turtles, depending on the region of catch. This is most significant in the Bay of Biscay, but in the North Sea, harbour porpoise is sometimes a victim to these nets.  

In the North Sea, bottom trawling is another fishing method with which seabass is caught frequently. With bottom trawling a net is dragged along the seafloor to catch bottom dwelling species. Because these species are non-shoaling species and are occurring amongst many others, bottom trawling is a mixed fishery with often high bycatch rates. In fact, seabass is not a target species, but bycatch themselves in fisheries using this gear type.
Bottom trawling can be extremely damaging to the seafloor ecosystem. When comparing the three main fishing methods for seabass, trawling is the least sustainable. 

How is wild seabass managed in Europe?

European seabass is managed under the Common Fisheries Policy although this is only partially effective for this species. There is no shared management plan with the UK on this stock. There are 5 different stocks in the Northeast Atlantic to make management and providing advice from ICES more specific. ICES gives advice on the maximum catch and minimum conservation references sizes (MSR), this advice has been in place since 1983. 

There is no total allowed catch (TAC), making seabass exempt from the landing obligation in commercial fisheries. In the Dutch North Sea, there is instead a landing restriction on seabass. Commercial trawlers are only allowed to catch a certain amount of seabass as bycatch, limited to a maximum of 5% of their total catch. Commercial line- and drift net fisheries also have their own fixed quotas. Besides the quota, there is also a closed season in place.  

Since 2015, new management measures were put in place, resulting in less seabass being caught which resulted in a predicted increase in biomass in 2020 (see figure 1.) 

Figure 1. Origin of catches in the Greater North Sea (ICES, 2021a)  

In the Mediterranean, wild seabass is not managed under the European common fisheries policy, as no fish from the Mediterranean is. Instead seabass fisheries in the Mediterranean are managed only on a national level, which has unfortunately led to a lack of effective management. 

Are there any social issues concerning wild catch of seabass?

Commercial vs recreational 

A social issue occurring with wild catches of seabass is the conflict of interest between commercial and recreational fisheries. Seabass is a popular target species for recreational anglers and commercial fishermen alike due to the high prices they can fetch. Anglers have played a significant role in seabass declines as seen in the figure below, which leads to lower quotas for commercial fishermen. 

Figure 1. Origin of catches in the Greater North Sea (ICES, 2021a) 

At the same time, recreational fishermen feel like they are under harsher restrictions, being only allowed to take two individual seabass per day, with a minimum size of 42 cm, with a risk of higher fines compared to commercial fishermen. Illegal catches are also a cause for much finger pointing between the two parties.  

Illegal Fishing 

There is a significant issue with illegal seabass fishing. Legal anglers have witnessed poachers using illegal catch methods such as lead lines with barbs and taking much more than the two fish per day they are allowed to catch. Also illegal placing of gillnets have been reported, and some commercial fishing vessels have been caught with more seabass onboard than regulations allow for.  

Although it can’t be verified, it seems as though the illegal anglers sometimes catch up to 10 kilograms a day, earning enough to make poaching their livelihoods. Often, these illegal catches are sold to local restaurants. From research done by Good Fish in 2018, this backdoor selling of seabass happens at a significant scale. Interviews with suppliers showed that they were offered seabass of up to 50kg by anglers who had spent long periods at sea on a regular basis. Besides the impact on the health of the stock, this illegal trade means a loss of control on matters such as hygiene and labelling as well. 

The Seaport police seize hundreds of kilos of seabass a year and the issue does not seem to be abating, even though poachers risk a fine of 1500 euros. It continues to be a problem, both an ecological and a social problem, as poachers have created a culture of intimidation, making recreational fishing less enjoyable.

What is the carbon footprint of farming or catching seabass?

Seabass is a true predator, a species high in the food chain, and therefore needs high quality feed. For farmed seabass this means that feed contains high levels of fish meal and oil to confirm to the dietary needs of the fish. Often these ingredients come from wild sources, especially when considering uncertified aquaculture, this means that fishing vessels are used to harvest fish to make those ingredients. As one can imagine, fishing vessels are reliant on fossil fuels which therefore contributes to Greenhouse Gas Emissions (GHGe).  

 In a study, it was determined that seabass in RAS systems have a global warming potential (kg CO2 equal to kg of fillet) of 3.6. However, most seabass is farmed in sea cages, which are expected to have a lower CO2 footprint, more comparable to salmon (1.8 in Norway, 3.3 in the UK). Nevertheless, compared to wild caught finfish the difference is estimated to be even higher. Farmed fish is said to have a 2-15 times higher climate impact than that of wild caught fish.  

 The carbon footprint of wild caught seabass mostly depends on the fishing gear type used to catch seabass. Bottom trawling is considered to have a very high fuel consumption, with beam trawling having the highest carbon emission due to the heavy weight and resistance created by dragging the equipment over the sea floor. Seabass is only caught as bycatch in this fishery, but due to the way quota is divided in the North Sea, wild seabass is most likely to have been caught with this gear type. 

 Passive fishing techniques like drift nets, long lines and handlines, have a significantly smaller fuel consumption. Therefore, this gear type does not have a high carbon footprint, especially compared to beam trawling and RAS aquaculture.  

 If consumers wanted a choice around CO2 when buying wild seabass, they should avoid bottom trawling. 

What season is this fish available?

Wild caught seabass is best when the spawning period is over, meaning outside the months of May and June. This is because the quality of the meat is better during this time. Despite this, Good Fish believes that although consuming fish outside the spawning season is important for the quality of the meat, it has no significant effect on the health of the stock. Therefore, seabass bought outside the spawning season is not automatically a sustainable fish. With farmed seabass, there is no defined season when it is best to buy them, as it is available year-round. 

Can I really not eat any seabass?

Our advice is to avoid buying European seabass in places where the origin of the seabass is difficult to check, such as in a restaurant or on the market. Only in the supermarket can you really read the packaging to ensure the seabass is certified sustainably.  

Wild seabass is unsustainable when caught as bycatch in trawl fisheries, giving a red score. Seabass caught with a gillnet is also not considered sustainable. Only seabass caught with hook and line can be considered sustainable, however because of illegal fishing it is still better to avoid buying wild seabass.  

It is possible to catch seabass sustainably yourself while angling recreationally, using a pole and line. The fish does have to be 42cm at minimum, and you shouldn’t take more than two individuals per day.  

While in a restaurant or on the market, it is best to choose another fish. Take a look on our VISwijzer to see which fish can be eaten sustainably.