Animal welfare in European caviar production: insights from sturgeon producers

Sturgeon are long-lived, late-maturing species and are typically maintained in captivity for many years prior to roe collection, raising distinct welfare considerations compared with most other farmed fish. European producers account for a substantial proportion of farmed caviar, yet little is known about welfare conditions in commercial sturgeon broodstock systems. This exploratory study examined European caviar producers’ perspectives on production practices and animal welfare. Semi-structured interviews were conducted with eight participants representing approximately 20% of European caviar production. Participants were recruited with support from the Federation of European Aquaculture Producers Sturgeon Commission. Interviews were transcribed and analysed using thematic analysis. Three main themes were identified: (1) history of caviar production and species used in farming, (2) living conditions for sturgeon and (3) market considerations and external pressures. Producers consistently described strong links between water quality, stress reduction and feed management and the quality of caviar, suggesting that economic incentives may align with certain welfare-supportive practices. Divergent views were expressed regarding traditional slaughter versus no-kill extraction, with perceived welfare and quality trade-offs in both systems. This study provides initial insight into European sturgeon farming practices and identifies priority areas for independent welfare assessment and future research.

Global caviar production has undergone a major transformation over the past three decades. Following severe overexploitation of wild sturgeon populations and their listing under CITES in 1997, the industry rapidly shifted from wild capture to aquaculture (1). Global sturgeon aquaculture has expanded considerably since then, with production now distributed across numerous countries and continents (2). Whereas global caviar production in the 1990s was estimated at approximately 3, 000 tonnes annually, current production is substantially lower and almost entirely farm-based (1, 3). European producers account for a significant proportion of global farmed caviar with 226 tonnes produced in 2023 (3).

The transition to aquaculture has reduced pressure on wild populations but has introduced new ethical and welfare considerations. Sturgeon are long-lived, late-maturing species, with farmed individuals kept in captivity for approximately a decade prior to first harvest (4, 5). Production systems vary from outdoor ponds to indoor recirculating systems, and roe is collected either through traditional slaughter or repeated non-lethal extraction (6). These biological and management characteristics distinguish sturgeon farming from most other aquaculture sectors and raise distinct animal welfare questions. Unlike salmon or tilapia, which reach harvestable size within months to a few years, the length of time to harvest for sturgeon results in cumulative welfare impacts, from chronic stress and disease to repeated handling for maturity assessment (6–8).

Animal welfare is increasingly recognised as an important component of responsible aquaculture (9). Animal welfare frameworks such as the Five Domains model emphasise that nutrition, environment, health and behaviour collectively influence animals’ mental states (10). For long-lived aquaculture species such as sturgeon, welfare considerations extend beyond slaughter practices to encompass many years of husbandry conditions and repeated management interventions (6).

Despite the economic value of caviar and the longevity of farmed sturgeon, there is limited published research examining welfare conditions in commercial broodstock systems. Existing literature on sturgeon aquaculture has focused primarily on growth, reproduction, nutrition and conservation (11–15). Comparatively little attention has been given to the lived experience of broodstock animals, cumulative handling stress, environmental design or welfare trade-offs between traditional and no-kill production systems (6).

Historically, assumptions that fish lack sentience or the capacity to experience pain have contributed to the marginalisation of fish welfare within aquaculture research and policy. Although this view has been increasingly challenged, its legacy continues to influence research priorities and industry practices.

Understanding welfare in specialised or emerging sectors often requires engagement with producers themselves. Animal welfare science increasingly uses qualitative approaches to explore management decisions, constraints and opportunities for improvement (16–18). Interviews with livestock producers have been used to identify barriers to welfare improvement and industry norms (19, 20). In aquaculture, studies have been conducted to better understand stakeholder perspectives of live transport (21), antibiotic use (22), climate change (23), among others. Limited stakeholder research is available in the context of sturgeon with the exception of bycatch of wild populations (24) and researcher perspectives on management (25). To our knowledge, no published study has qualitatively examined European caviar producers’ perspectives on sturgeon farming practices. Therefore, the aim of this exploratory study is to investigate how European caviar producers describe their production systems, management practices and perceived welfare considerations. Specifically, we sought to identify perceived barriers and opportunities for improving the welfare of sturgeon farmed for caviar.

Positionality statement

Wasseem Emam is an animal welfare researcher working on improving welfare standards in aquaculture, including collaborative projects with fish farmers and industry stakeholders. Matthew Unerman is a research assistant at Ethical Seafood Research. He contributed to the drafting and editing of this manuscript and was not involved in data collection, coding or interpretation of findings.

Interview design and data collection

Ethical approval was received from Kafr El-Sheikh University (Approval number KFS-IACUC/278/2025).

This study employed open-ended interviews following an exploratory qualitative design. An interview guide was developed (see Supplementary Appendix 1) including demographic questions and open-ended questions. Given that this is, to our knowledge, the first interview study with caviar producers, our aim was to conduct interviews that include a broad range of open-ended questions to allow participants to guide the discussion. Participants were a convenience sample (26) of European sturgeon producers recruited with the assistance of the Federation of European Aquaculture Producers (FEAP) Sturgeon Commission. The FEAP Sturgeon Commission sent a recruitment letter to their members (see Supplementary Appendix 2) and discussed participation with members during meetings. Additionally, caviar producers known to one of the authors (Emam) were contacted directly.

Participants who indicated interest were sent the consent form ahead of time and asked to review the document. Each interview began with the interviewer reading through the consent form; if the participant had not signed the form in advance, they were asked to provide verbal consent on the recording. Interviews were completed virtually using Google Meet video conferencing. Interviews were recorded and transcribed using Google Meet, with transcripts subsequently compared to the recording to ensure accuracy.

Data analysis

All data were anonymised by removing identifying information and assigning each participant a numeric identifier (e.g., P1, P2). Participants were provided with a copy of their transcript and given the opportunity to remove content and clarify any statements.

Thematic analysis (27) was applied to the interview data. This study adopted a qualitative approach to prioritise depth of insight and contextual understanding over quantification. Given the sample size and exploratory nature of the research, themes were not quantified, as frequency counts may imply a level of generalisability not appropriate for qualitative data.

A codebook was developed through an iterative process in which initial codes were generated through close reading of the transcripts and subsequently refined into child codes, parent codes and broader themes. Themes were developed based on patterns of meaning across participants rather than frequency alone. Coding and theme development were reviewed and discussed among authors to ensure consistency and interpretative rigour.

Quotes were selected to represent key themes and to illustrate both commonly expressed views and variation across participants, and in some cases have been shortened with ellipses (“…”) for readability. Recruitment continued until thematic sufficiency was reached, whereby no substantially new themes emerged.

Participant characteristics

Eight interviews were conducted, comprising six individual interviews and two group interviews (Table 1), from June to August 2025. Participants were producers in Sweden, Spain, France and Belgium. Participants in this study account for approximately 20% of European caviar production, with a total annual production of 52.5 tonnes (based on a 2023 estimate of 226 tonnes of caviar produced from European farms; 3). Additional demographic information for participants is presented in Table 1. Average interview length was 60 minutes (range 47–75 minutes).

Results are presented under three main themes: (1) history of caviar production and species used in farming, (2) living conditions for sturgeon and (3) market considerations and external pressures.

Thematic findings

The following sections present the main themes identified through analysis, with illustrative quotes selected to represent key patterns and variation across participants.

Theme 1: history of caviar production and species used in farming

This theme captures producers’ accounts of the transition from wild sturgeon harvest to aquaculture and the rationale behind species selection in modern caviar production. The following quotes illustrate how producers described this historical transition and their choice of species. The addition of sturgeon to the endangered species list in 2006 resulted in a major shift in the industry:

“in two to three years, the industry of caviar passed from 100% wild sturgeon to 100% farm caviar.” [P8].

This change in the source of sturgeon impacted global production substantially:

“we’re talking about a market of about 2, 000 tonnes, let’s say 20 years ago and now we are just at 700 tonnes.” [P6].

Today, participants acquired their sturgeon from a variety of sources depending on restrictions in their country. Some grew their own stock using collection females — with one producer stating they will use the same collection female until she reaches 40 years old — and hatcheries, whereas others acquired adult sturgeon from other producers. Managing disease risk was seen as an important aspect of acquiring new stock, as introduction of disease has the potential to affect ten years of production:

“it’s very dangerous to transport from one country to another because you can transport sturgeon, but also you can transport disease.” [P4].

Participants farmed several different species (see Table 1) and these decisions were based on many factors. In some cases, producers chose species based on import regulations in their region. For others it was due to differences in yield between certain species or the temperament of the fish. For example, one producer described why they have stopped farming Acipenser stellatus:

“we also have some stellatus but that’s something we’re not really planning to continue. The main reason is that the yield of stellatus is not as good as with other species … and the quality of the caviar is less. So, it’s not a very interesting market for us. Also, the fish are way more nervous. So, they jump a lot … For aquaculture in a closed system, they’re not an ideal species … With the caviar you have to wait a very long time before you have mature fish. If you make, let’s say, a bad decision and you decide to try stellatus and it doesn’t work out and you’re still stuck with the fish for a long time.” [P7].

Theme 2: living conditions for sturgeon

The following quotes illustrate how producers described living conditions and management priorities for their sturgeon.

Participants discussed the importance of optimising living conditions for sturgeon. One producer using no-kill methods described their philosophy:

“small volume, treat them well, give them maximum optimal living conditions, have them living for 20 years, giving us five harvests over time. Then that gives us a chance of maybe recovering our money.” [P1].

Stocking density was one of the key factors influencing living conditions and varied widely across farms and life stages. Adult sturgeon stocking density ranged across participating farms from 10–60 kg/m³ and was managed to ensure health and product quality were not compromised:

“we keep the stocking density of approximately 40 kilos per cubic meter and there they live. Since we are very focused on product quality being a caviar producer, we cannot compromise. I mean if we were a fish meat producer we would of course stock very densely. We would maximise volume and we would just keep them until they scream, basically. But we can’t do that … that would harm our product quality so we have to have less fish per cubic meter.” [P1].

Participants frequently described that higher stocking density led to the sturgeon scratching and injuring each other.

For participants that farm in indoor systems, the topic of environmental enrichment was raised:

“We have this discussion with other fish farmers and welfare associates. They ask how fun is it for a fish to live inside in a pool? I mean, isn’t it boring for the fish? And then my first answer is always, well, if you have to choose between being a bored fish and a dead fish, maybe they prefer to be a bored fish. And then they say, you should have your pools more resembling the natural habitat with stones and rocks and flowers and things in the pool…. resembling the river or lake where they come from. And we don’t object … that would create a lot of bacteria that would stick there. It basically means adding a biofilter in the pools and stones would sort of get loose and fall around in the filters, plug the pipes, and so on.” [P1].

Subtheme: product quality

According to participants, product quality was related to three main characteristics: water quality, stress and feed quality:

“if you want to summarise this long interview, genetic material, quality of water, no bloody stress and good timing for the maturation, good timing of crop of harvesting. If you have that, you can have superb caviar.” [P3].

Water quality impacted product taste directly:

“[if] the animal has been in water which is not very good and has a lot of mud and so on, the caviar will taste like mud.” [P2].

Stress on the animal impacted both product quality and longevity, and was prioritised particularly in handling procedures:

“I’m always saying to the other workers, please handle them carefully, we don’t want to harm them. They have to live a long and happy life and this is what gives you the money every month. I think that we’re doing all that we can to have a good world for the animals.” [P2].

Diet was an important aspect of production as it directly impacted caviar quality:

“the egg is filled with fat. It has to contain a lot of energy for the larvae to grow … if you don’t give the fish the right building blocks to make a good membrane, then your membrane is going to be soft.” [P7].

Participants also discussed how overfeeding impacted product quality, and having ‘fat fish’ resulted in an inferior product:

“sturgeon are the fish in aquaculture that we give less feed because our objective is to produce caviar. It’s not to produce meat or fat sturgeon. We want quality … we don’t want to have big fish with a lot of fat, [they] don’t give a very good caviar so we reduce [the food].” [P4].

For all of the considerations above that impact product quality, participants frequently described strict procedures to monitor the animals:

“we have traceability from the eggs to the eggs. We can control all from the eggs from the hatchery to the eggs of the consumer … We have all the story, say it’s 10 years of production … if you have a problem at one moment you have to know the story … It is good for the health but it’s also very important for us to try to find if there is a correlation between a problem in one period and the problem we have at the end.” [P4].

This traceability was viewed by participants as important because it allowed producers to pinpoint issues in production, address consumer complaints and modify their practices to avoid similar issues in the future.

Participants also discussed health and monitoring procedures, including physical exams and preventative management such as vaccinations. As described by one participant:

“We chip each fish if they’re not already chipped when they come. We track them over life. We see how they grow. We see the mortality rate. There is still some mortality, of course. We try to avoid fish diseases. We haven’t had any major ones yet. We have technical accidents. Although we have sensors everywhere, we have video cameras. We have everything. It’s still … that shit happens basically and although we have sensors and alarms connected to everyone’s telephone when they ring at 3:00 at night sometimes people don’t wake up … we do have technical accidents every year and we lose a few fish in that way.” [P1].

When it came to antibiotic use, participants frequently described alternative management practices they would use before employing antibiotics. Several participants vaccinated their sturgeon against common conditions and monitored water quality and disease introduction to minimise the need for antibiotics:

“we work for a long time to find a treatment without impact on the environment or less impact and the objective is not to use antibiotics. Sometimes the problem is too important and so we need to use [antibiotics], but the objective is to use less because we know that it could be a problem for the environment and bio-resistance.” [P5].

Subtheme: roe collection

Participant farms varied in their method of caviar production, whether traditional or no-kill, or a combination of both. In terms of determining when it was time for harvest, practices were similar across both types of production and started with a physical exam and ultrasound:

“each fish is being scanned I would guess four times a year. It’s just like with the baby in the pregnant mothers. In the pregnant mother, you see when the caviar builds up and you can see when it’s time for harvesting.” [P1].

Some farms performed a biopsy to obtain a sample of eggs before slaughter:

“we put the fish to sleep in tanks. We take a scalpel and take out let’s say four, five eggs for us to decide if it’s the good time for processing or not. It’s a question of millimetres, for example, the good size for us is 3 millimetres and more. But if the eggs are just at 2.7, 2.8 mm of mean size, that’s too small.” [P6].

For those that employed traditional methods, captive bolt stunning (a mechanical method used to render fish unconscious prior to slaughter) was the most common method of slaughter.

Age at first collection (no-kill) or slaughter (traditional) varied widely between farms and species:

“the sexual maturity of the female is different according to the species. So it’s seven years for baerii, eight years for gueldenstaedtii and 14 years for beluga in our conditions. Which is quite good because the vast majority of my colleagues will tell you more like eight years for baerii, something like 9 to 10 years for gueldenstaedtii and over 16 years for beluga.” [P3].

Two of the farms in our study used no-kill caviar production practices. The operations transitioned to no-kill farming for a variety of reasons including animal welfare considerations, public pressure and the perceived benefit of recouping costs through multiple harvests per fish:

“we hope in the long run to obtain maybe five, six harvests from each individual. We are right now recording a fourth harvest from many of them.” [P1].

As one producer explained, their farm was acquired by a larger company and subsequently transitioned to no-kill production:

“[the new owners] didn’t like that we killed the animal for obvious reasons. So they decided that we should try the non-killing process. So right now, we’re actually doing both with slaughtering and non-slaughtering … [the new owners] saw that we needed 16 to 18 years to produce caviar and [sturgeon] produce only once, they said okay I don’t like that … They say well, we have to make it happen.” [P2].

Some producers still using traditional methods had concerns about no-kill production:

“[for no-kill production] the caviar is quite poor quality, sorry to say that … and regarding the respect of the animal … I know that in some operations after extraction, 20% of the females die in conditions that you can imagine, septic, big infection. So, I mean I prefer to develop techniques to euthanise the fish with CO2 in order to put them to sleep and then to use electro-stunning … get something clean, rather than to take the risk of that.” [P3].

Time between harvests for no-kill production was approximately 18 months for participants, and was influenced by environmental conditions, particularly water temperature:

“average was 18 months or 17.6 months actually, when we did last time … and we can affect that by the warmer we keep water during the year. We have to heat our water in winter and cool our water in summer … the higher we keep [the temperature] up in the cold period of the year, the shorter the time between harvests.” [P1].

Longer periods between harvests also allowed the caviar to develop and resulted in a larger yield.

Theme 3: market considerations and external pressures

The following quotes illustrate how producers described market pressures and external factors affecting their operations.

Subtheme: cost of production

One challenge for participants was the high cost of production given the length of time to first harvest:

“it’s almost economic suicide to farm sturgeon.” [P1].

With rising costs of operations through increased energy, land and resources, producers described the need for “deep pockets” to survive:

“the first eight, nine years you’re not making any money because the fish has to grow.” [P7].

When producers discussed the financial challenges their industry was facing, there was acknowledgement that caviar is a luxury product affecting a small, often wealthy consumer base. When describing the potential collapse of the industry, one producer offered this perspective:

“I mean a few US bankers maybe would suffer … starving people in Africa will not cry if there is no black caviar … It’s not a catastrophe for the world, but for our little industry, the challenges are economic.” [P1].

In the past, many producers began farming sturgeon for meat but low market prices for fish led to a transition to caviar production:

“in the past, very long past, they used to eat meat of sturgeon. But at the moment … it was just the packaging of the caviar. It is not meat. It is packaging of the caviar.” [P4].

However, it was important to some producers that the whole fish is used rather than discarded:

“we sell 100% of our meat. We don’t put the meat aside … when the female of 10 years gave us caviar we need to go to the end and the respect … So we don’t earn money on it … They have given us some pleasure of [caviar]. We have to go until the end and to be sure that we use the totality of [the sturgeon].” [P4].

Several of the farms in our study began with a different species and transitioned to sturgeon, resulting in facilities that were not built specifically for sturgeon and either needed to be retrofitted or did not meet current needs:

“the tanks are quite deep, which is not really necessary for sturgeon. And they are mostly on the bottom. So you don’t really need deep tanks, which only makes it harder for us to get the fish out of the tank.” [P7].

Participants discussed the perceived environmental impact of sturgeon farming, including water use and concerns about farmed sturgeon as an invasive species. In terms of water use, one participant described the need to justify groundwater consumption politically:

“to produce 1 kilo of protein from fish, it’s the lower quantity unit of water compared to chicken, pigs or cow. We know that. But of course we need water.” [P6].

One participant using an indoor system described the regulatory constraints that applied to their farm:

“you would expect the fish to be in the river. That’s where God placed them. I mean 250 million years ago. But we are not allowed. The Siberian sturgeons are, by our authorities, considered an invasive species. They are afraid that we would somehow contaminate or harm the salmon living in the river. So we must be inside … we are forced to live on the third floor of the paper mill.” [P1].

Subtheme: competition and other stakeholders

Participants spoke extensively about increased competition from other regions, particularly China. China’s production has grown exponentially, and government subsidies enable Chinese caviar to be sold for considerably less than European products:

“in 2016 China produced… 80 tonnes and that was maybe 20% of global production. Today they produce almost 300 tonnes and they are 60% of global production.” [P1].

Participants recognised the value of competition in principle but felt that subsidies created an unfair advantage:

“competition is good and if [other producers] are more efficient and better and smarter, then that’s so. But if they are being subsidised, which people believe, then that’s bad of course for fair competition.” [P1].

“we sell around 1, 000 euro per kilo and they were selling for I think around 300 per kilo. So it’s very very very very low and they produce high quantity and very fast.” [P2].

Producers found ways to increase their competitiveness, including working collaboratively with other producers. One participant described this shift as particularly meaningful:

“change our mindset, change the paradigm and we are going to work together. We are going to share our knowledge all together … because we were working that way, in fact I’m very proud of that. Because it is still a fantastic human experience, because we passed from enemies to friends … When you are at the origin of such a human adventure, I mean, you can die after that … I’m very proud of that and of what we did with my friends and … we were sharing the same values regarding fish farming.” [P3].

Participants also described learning from producers in other regions:

“we had the chance to have Iranian people … because they have no more sturgeon in their country. So they came and we worked together … and gave us their techniques … We have experimented during 10 years and we mixed the two to make our system today.” [P4].

In contrast, some participants expressed that being the only sturgeon producer in their country made it difficult to acquire industry knowledge or access specialists, which was a barrier to improving production.

Participants felt strongly that they had a role to play in working with advocates, conservationists and researchers:

“[Emam — study author] contacted us through FEAP and said okay it’s important for the farmer to be in contact with NGO like you … I’m happy that you look to have an open mind, and you didn’t ask us if it was normal to kill the fish for eating eggs or things like that. I mean you are not aggressive … it’s important to show to the people that sometimes farmers and NGO … we are not opposite.” [P4].

Participants viewed the work that they do as a contribution to the conservation of sturgeon species:

“[we worked with] WWF to help them do a little bit of research, help them find techniques. For example, how they can see the difference between farmed caviar and wild caught caviar. So, we provide them with samples, so they can do testing. Those things are all very exciting and it’s fun … The company is not really making money on it, but we can still help and we’re always taking the opportunity to help. That’s really nice to make a small difference in the conservation of sturgeon … I think most farmers also realise that we’re not enemies of the conservation of sturgeon.” [P7].

Participants similarly expressed interest in research that supports and improves industry practices, alongside frustration at the limited applicable research on mature broodstock:

“most researchers need to publish as much as possible. So all the research you find on sturgeon is with small fish, young fish. So there’s very little long-term research on sturgeon except for what the farmers do and then it’s never published. So it’s very frustrating if you want to read or find something out about sturgeon. All you find is yeah six weeks old, one month old and that’s a big problem … I’m sure that the 10-year-old sturgeon doesn’t have the same nutritional demands as a six week old fish.” [P7].

Because sturgeon farming is a relatively new industry, participants perceived this as an opportunity to participate in innovation:

“what I really like about the caviar industry or sturgeon farming, let’s say, is that it’s all relatively new. We still have a lot of things to discover … So what is really nice about the sturgeon farming is that you can still make a difference that’s bigger. So every day we’re learning … there’s still a lot of possibilities to do better.” [P7].

For this reason, and because some participants were early producers in this novel industry, several considered themselves pioneers and expressed pride in the contributions they had made.

Subtheme: product differentiation and marketing

To overcome competitive challenges, producers described looking for ways to differentiate their product. This included increasing transparency in the production process, describing the origin of the product and advocating for a pricing model that reflects product quality. One producer drew an analogy with the wine industry:

“for wine or for other things, you will have different levels of price. Today the problem is that people are thinking about one product of caviar — that’s not true … the Chinese caviar is not the same [as] French caviar or Italian caviar … In the wine [industry], you have wine that you can use with a bottle with a good price, good wine, but you have also big wine that is very expensive. I think in the future that’s what will happen in caviar.” [P4].

To differentiate their product, some producers pursued formal certification schemes. One farm is certified organic and producers in France collaborated to obtain a Protected Geographical Indication (PGI), certifying the origin and quality of the product:

“it’s great because at the end of the day we are the only producers in the world with a guarantee of origin 100%… the origin is of the egg, the fingerlings, the fish, the caviar, everything from the egg to the egg. We also are the only one giving to our customer B2B or B2C 100% of transparency on our processes — farming processes, transformation processes and commercial processes. We are the only one guaranteeing to our customer no use of GMO for the soil, no use of antibiotics during the farming process.” [P3].

Participants also discussed the challenge of attracting new consumers, noting a generational shift in their customer base:

“we hope the world population will develop the consumption of caviar. That’s also a problem for us because when we see the range of people who consume caviar, the people become older and older. We have a real challenge to catch the new generation of customers … because today if you take the example of millennials, unfortunately they don’t have the idea of caviar … [or] have the money to pay such a product.” [P8].

This exploratory study provides one of the first qualitative insights into European caviar producers’ perspectives on sturgeon farming. A key theme across interviews was the link between husbandry conditions and product quality. Producers repeatedly described water quality, stress reduction and feed management as critical factors influencing caviar quality, a phenomenon that is well supported in the literature (28). This suggests that certain welfare-supportive practices such as optimal water quality, feed quality and habitat may result in increased economic returns, a pattern that has been noted in other high-value aquaculture sectors where the economic cost of poor welfare can be internalised into product outcomes (29).

The long lifespan of sturgeon in aquaculture introduces unique welfare considerations. Participants frequently described that sturgeon are kept up to 14 years before slaughter or first harvest, depending on the species. Other research has shown that sturgeon may be maintained in captivity for more than a decade prior to harvest (6). During this time, fish are subjected to repeated monitoring, handling and environmental conditions that differ substantially from their natural habitats (6, 30, 31). The topic of environmental enrichment was raised by participants, specifically for those in indoor systems. Environmental enrichment can positively impact the welfare of captive fish (see review by 32), which may be especially important given the length of time sturgeon are kept for production. Additionally, these long production cycles mean that welfare assessments must consider the cumulative effects of husbandry practices across many years, rather than focusing on any single management event (6). This represents a significant gap in current aquaculture welfare science, which has largely been developed for shorter-lived species.

Participants expressed differing views regarding traditional slaughter and no-kill roe extraction. While some producers viewed non-lethal extraction as a welfare improvement, others raised concerns about infection, recovery and product quality. These differing perspectives, and the lack of behavioural or physiological literature into the different approaches, highlight the need for independent research comparing the welfare implications (see also 6). The divergent views also reflect a broader challenge in evaluating welfare trade-offs across production systems where both approaches carry distinct costs and benefits for the animal. No-kill extraction avoids lethal slaughter but introduces risks of physiological stress, surgical or stripping-related injury and post-extraction infection (6). Some producers cited post-extraction mortality rates that were not trivial; however, validation of these results through on-farm studies is warranted. Conversely, traditional slaughter when preceded by effective stunning (33) may result in a more rapid and irreversible loss of consciousness than the protracted recovery period that can follow no-kill procedures. Further research is needed to better understand the welfare implications of slaughter and harvest practices in sturgeon.

Beyond the point of harvest, both systems involve animals maintained in captivity for many years under conditions that may differ substantially from their natural habitat, particularly for indoor-housed sturgeon. Wild sturgeon can travel vast distances; the green sturgeon migration rates exceed 50km per day (34). Confinement for species that are known to travel extensive distances can lead to stereotypic behaviours (35). Given that intensive caviar production is a fairly new industry, further research is needed to determine the impacts of captivity on sturgeon.

Confinement of long-lived, migratory species may have implications for behavioural expression, including the potential for stereotypic or maladaptive behaviours. Several participants described manipulating environmental parameters such as water temperature and photoperiod to influence reproductive cycles and reduce time between spawning events. These practices suggest an applied understanding of circadian and circannual rhythms, as well as the role of environmental cues (zeitgebers) in regulating physiology and behaviour. While such interventions may improve production efficiency, their welfare implications remain insufficiently explored.

Similar patterns have been observed in other migratory species. For example, migratory restlessness in Japanese eels has been linked to environmental and hormonal cues (36), suggesting that confinement may disrupt natural behavioural drives in species with complex life histories.

Producers also emphasised the limited availability of applied research on mature broodstock sturgeon. Much existing research focuses on juvenile fish or short production cycles, reflecting the tendency for studies to be conducted with smaller animals at earlier life stages (37). This highlights the need for a more holistic approach that considers changing welfare needs across the lifespan and in relation to dynamic environmental conditions (38). Greater collaboration between researchers and producers may therefore help address knowledge gaps relevant to welfare, husbandry and system design, and could yield findings that are more directly applicable to industry practice.

Producers in this study were notably open to engagement with researchers, conservationists and animal welfare organisations. Several described existing collaborations with conservation bodies and academic researchers as professionally meaningful, and one producer commented explicitly on the value of a non-adversarial framing in relationships between farming and welfare advocacy. This openness suggests that the European caviar sector may be receptive to formal welfare engagement, provided that researchers approach industry stakeholders in a practically-oriented and non-judgemental way. Given that animal welfare is such a complex topic (sometimes referred to as a ‘wicked problem’), involving multi-stakeholder groups can lead to more successful outcomes (39). Building on the existing relationships between stakeholder groups through joint on-farm studies, shared development of welfare indicators or inclusion of welfare criteria in certification frameworks could represent a productive pathway for advancing sturgeon welfare in this sector.

Finally, the global caviar market was perceived as undergoing rapid change, particularly due to increased production in China (6). European producers described efforts to differentiate their products through quality, traceability and origin labelling, including through formal certification schemes such as Protected Geographical Indication (PGI) status, which guarantees that a product originates from a specific region and possesses qualities attributable to that origin (40). While many of the certifications discussed by participants were to differentiate their product from a marketing perspective, certification schemes have been shown to have a benefit on animal welfare outcomes (41). Participants also noted a generational shift in the consumer base, with concern that younger consumers are less familiar with, and less likely to purchase, caviar. Whether the growing availability of lower-priced products from expanding markets will attract new consumers or further fragment the premium segment remains unclear. Animal welfare could potentially form part of European producers’ differentiation strategy if supported by credible, independently verified welfare indicators — particularly in markets where consumer concern for animal welfare is high (42, 43). This may represent a viable pathway for aligning welfare improvements with market incentives in high-value aquaculture systems.

This study identifies several priority areas for future research. On-farm studies employing animal-based welfare indicators would complement the producer perspectives gathered here and allow independent verification of the husbandry conditions described. Specific areas warranting investigation include: the effects of stocking density and system design on behaviour and physiological stress in adult broodstock; the welfare implications of repeated handling, ultrasound and biopsy procedures across multi-year production cycles; comparative welfare assessment of no-kill extraction and traditional slaughter using validated indicators; and the feasibility and welfare value of environmental enrichment compatible with biosecurity and water quality requirements. Given China’s dominant position in global production, an equivalent qualitative study with Chinese producers would be of considerable value for understanding welfare conditions across the sector at scale.

This study provides an initial exploration of European caviar producers’ perspectives on sturgeon farming. Producers described management practices aimed at maintaining water quality, minimising stress and ensuring product quality, yet variation in production systems and roe extraction methods indicates that welfare conditions may differ substantially between farms. The long lifespan of farmed sturgeon presents unique welfare considerations that remain under-studied in aquaculture research, and both traditional and no-kill production systems involve welfare trade-offs that require independent empirical investigation.

Further interdisciplinary research combining welfare science, veterinary expertise and industry knowledge will be essential to better understand and improve welfare outcomes for sturgeon farmed for caviar. The willingness expressed by producers to collaborate with researchers and welfare advocates offers a promising foundation for this work. These findings also highlight the importance of extending high welfare standards to aquaculture systems and species that have historically received limited attention within animal welfare science.