Investigating the vulnerability of European Seafood Production to Climate Warming

By: Gaitlyn Malone, SRC Intern

As the world’s climate continues to change, economic, social, and environmental changes will undoubtedly occur along with it. One sector that is expected to be economically affected by climate warming is seafood production (Breitburg et al., 2018). Seafood production, which includes both farmed and captured fish, shellfish, and seaweed in marine and freshwater, will experience changes since the warming of an environment has the ability to change both a species’ distribution and life history characteristics (Pecl et al., 2017; Cochrane et al., 2009). Therefore, it is crucial to work towards being able to predict and understand the extent of these changes in order to prepare for the future.

A recent study (Blanchet et al., 2019) examined the effects of climate change on seafood production within each European country in order to identify potential challenges and opportunities within the sectors of marine fisheries, marine aquaculture, and freshwater production. To do so, the researchers combined information on the target species’ temperature preferences, life history characteristics, and production volume to determine their biological sensitivity (BS) and the maximum temperature (Tmax) that they were experiencing. They then determined the adaptive ability of seafood production in each country or sector by determining the number of species that the country/sector exploits and those species’ temperature ranges. A country or sector that exploits a higher number of species will be more likely to adapt in response to climate change. A species with a wide temperature range would also potentially be more adaptable since they are able to withstand a variety of temperatures.

Figure 1: Biological sensitivity index versus the temperature range of each species within the sectors of a) marine fisheries, b) marine aquaculture, and c) freshwater production. The size of the bubbles relates to the total volume produced for each particular species in that sector (Blanchet et al., 2019).

Figure 2: Ranking of each European country’s vulnerability to warming based on their weighted temperature sensitivity and weighted biological sensitivity for each of the three production sectors. The size of the bubbles represents the relative contribution of each country to the total European production volume within that sector (Blanchet et al., 2019).

Overall, seafood production was found to generally be more vulnerable within the marine fisheries and aquaculture sectors. The freshwater sector varied greatly based on country. Within the marine sector, northern countries tended to be more sensitive to warming than southern countries since seafood production in these areas are more dependent on cold-water species with a high BS. Southern countries tended to rely on warmer water species that had a lower BS. The main challenge facing these marine fisheries is due to changes in species distribution. In response to warming, there has been a northward expansion of the range of several species, which in some cases has included a contraction of their southern range. This change in distribution has the ability to affect local fisheries and management, who in southern areas may lose access to their resources, while northern areas may benefit. Aquaculture taking place in temperate zones was also predicted to be at risk from warming conditions, since increasing temperatures have the ability to reduce oxygen levels in the water and increase the metabolic costs for organisms. Disease is also likely to increase in these systems since pathogens may spread more readily. The low amount of species diversity in aquaculture also makes it particularly susceptible to rising temperatures.

Under warming conditions is not impossible to continue producing sustainable seafood, however efforts must be made to adapt to climate change. Therefore, the authors suggest that there must be communication between stakeholders, diversification of exploited species, and transnational cooperation in order to meet these goals.

Work Cited

Blanchet, M.-A., Primicerio, R., Smalas, A., Arias-Hansen, J., Aschan, M. 2019. How vulnerable is the European seafood production to climate warming?. Fisheries Research 209, 251-258.

Breitburg, D., Levin, L.A., Oschlies, A., Gr.goire, M., Chavez, F.P., Conley, D.J., Gar.on, V., et al., 2018. Declining oxygen in the Global Ocean and coastal waters. Science 359 (6371).

Cochrane, K., Young, D.C., Soto, D., Bahri, T., 2009. Climate change implications for fisheries and aquaculture: overview of current scientific knowledge. FAO Fisheries and Aquaculture Technical Paper 530, 212.

 Pecl, G.T.,, M.B., Bell, J.D., Blanchard, J., Bonebrake, T.C., Chen, I.-C., Clark, T.D., et al., 2017. Biodiversity redistribution under climate change: impacts on ecosystems and human well-being. Science 355.



Masked, diluted and drowned out: how global seafood trade weakens signals from marine ecosystems

By Jake Jerome, RJD Graduate Student

It has been shown that global seafood trade inherently drives seafood production, negatively impacting marine ecosystems worldwide. While it is well known that these ecosystems are deteriorating, most research has been focused on global stock assessments, catch trends, or fisheries dynamics, with little attention given to researching the ways in which global trends are linked to consumers through trade. Fish prices can potentially be used as a feedback signal to consumers about the state of fisheries and marine ecosystems, but this method faces several issues. Crona et al 2015 dive deeper into the usefulness of using fish prices as a feedback signal, but develop a set of mechanisms that combine to weaken this signal from global trade to consumers.

The first mechanism that weakens price signals is masking. Masking occurs within individual fisheries and consists of two parts. First, negative impacts that arise from fishing are often separated from the operating cost of the fishery. For example, fisheries may cause habitat destruction or result in bycatch of endangered animals, but neither of these have a large impact on the yield or cost. Second, short-term catch trends may not provide accurate representation of target stock declines due to factors such as increased effort, technological advances, and fishing deeper or farther from shore.


Shrimp trawl net with bycatch (Elliott Norse, Marine Conservation Institute/Marine Photobank)

The second mechanism discussed is dilution. Dilution occurs when the amount of supply that an individual fishery has declines but is hidden from consumers by using the supply from another resource area. For example, the UK imports Atlantic cod from Iceland and Faeroes to make up for the decline of North Sea cod. Through dilution, changes in any one ecosystem are concealed from consumers because substitutable products are made available from different ecosystems.

A third mechanism examined is the ‘drowning out’ of price signals. This is usually due to other market factors that affect fish prices. Things like changes in consumer spending patterns or price/availability of alternative protein sources can combine to alter fish prices that do not necessarily connect with ecosystem or species decline.

Chilean Seabass for sale at Whole Foods (Gerick Bergsma 2011/Marine Photobank)

Chilean Seabass for sale at Whole Foods (Gerick Bergsma 2011/Marine Photobank)

In conclusion, the authors suggest that the feedback from individual fisheries to consumers worldwide is highly asymmetric and that price signals reflecting changes in the source ecosystem typically are masked, diluted, or drowned out unless large proportions of seafood stocks collapse. Despite this, opportunities do exist that possibly could help provide a positive feedback signal to consumers, resulting in promoting sustainable seafood practices.

Source: Crona, B. I., Daw, T. M., Swartz, W., Norström, A. V., Nyström, M., Thyresson, M., Folke, C., Hentati-Sundberg, J., Österblom, H., Deutsch, L. and Troell, M. (2015), Masked, diluted and drowned out: how global seafood trade weakens signals from marine ecosystems. Fish and Fisheries. doi: 10.1111/faf.12109

What’s for Dinner: Seafood Fraud

by Lindsay Jennings, RJD Intern

Whether it is a grouper sandwich, a salmon filet, or a fresh sushi roll, there is a growing demand for seafood on the global menu. Over the past years, there has been an increase in seafood consumption, as an expanding list of marine life is appearing on menus at fast-food eateries, take-out dining establishments, and fine dining restaurants.

This increase in consumption, though, has given rise to a practice known as seafood mislabeling, or seafood fraud, whereby one species of seafood is substituted with a less desirable, cheaper, or more readily available species. Typically similar in taste and texture, certain marine species are difficult to identify without diagnostic body parts such as its head, skin, fin, or shells. Once filleted and prepared, it is often difficult to decipher the exact species that is being served.

Photo 1

Species which are commonly mislabeled include Atlantic cod, grouper, swordfish, red snapper, and wild salmon. When processed, these species become extremely difficult to identify

Seafood fraud is detrimental for multiple reasons. First, it can threaten human health as certain fish species contain high concentrations of contaminants and toxins (1). King Mackerel generally contains high concentrations of mercury, and Escolar (typically sold as white tuna) produces a toxin that leads to gastrointestinal issues. Unknowingly consuming these species can pose serious health risks. Second, global fish stocks face increasing pressure daily from exploitation and overfishing. Mislabeling can create and sustain markets for illegal fishing (2). As laundering illegal species becomes easier, conservation efforts become weakened. Shockingly, according to the US Government Accountability Office, only 2% of seafood imported into the US is inspected and of that, only 0.001% is inspected for fraud (3).

Photo 2

FDA field inspectors checking shipments of imported seafood

 Mislabeling can also undermine consumer’s choices by making it difficult for them to accurately make a sustainable seafood purchase. And finally, it misleads the public about the truth surrounding the availability and conservation status of certain species (3). Instead, it gives an exploited fish species, such as Grouper, the false appearance of having a steady supply.

Fortunately, a number of studies are helping to educate and bring awareness to the severity of seafood fraud and more importantly potential solutions to counter the prevalence of this issue. Hanner et al., in 2011, found 41% of their 254 Canadian seafood samples to be mislabeled. Pacific salmon was often not designated to a species level (e.g. Coho, Sockeye, Pink), Red Snapper was commonly swapped with Tilapia, and there were instances of Patagonian Toothfish being labeled as Chilean Seabass; all of these examples of mislabeling (4).

To help study and combat this practice, researchers, including Hanner, have been using DNA barcoding, where they match genetic material of a fish sample against known genetic sequences, or barcodes, in a database. The benefit of using DNA barcoding is its ability to match barcodes from whole fish, fillets, fins, juveniles, eggs, and even samples of cooked or frozen fish! As our voracious appetite for seafood consumption outpaces the supply, global fish stocks continue to decline. DNA barcoding offers an effective way to increase transparency, fair trade, and ultimately ensure a more sustainable future for the global seafood industry and for stronger fisheries resource management.

Photo 3

NOAA scientist sampling a piece of fish for DNA analysis

Organizations like Oceana have also produced studies shedding light on seafood fraud. From 2010 to 2012, they analyzed over 1200 seafood samples across the United States, and found a mislabeling rate of 33% across 21 states (1). Popular metropolitan cities such as Miami, Washington DC, Seattle, New York City, and even land-locked cities like Austin, Denver, and Kansas City were culprits. With numbers from these studies, a conservative worldwide mislabeling rate of just 10% would indicate that there is around $24 billion in fraudulent seafood shipped worldwide annually (4)! Studies have also uncovered widespread mislabeling in Brazil, South Africa, the Philippines, Italy, and the UK, which supports the reality that seafood substitution is not confined by geographic boundaries or species.

Coupled with these studies that raise awareness about mislabeling, increased education of consumers can be another effective tool for the conservation of commercially harvested species that could be threatened or endangered. Miller et al. in 2011, examining mislabeling in the UK and Ireland, found Cod mislabeling to be about 4 times lower in the UK than Ireland. This was credited mainly to heightened consumer awareness in the UK despite the same EU policies for seafood traceability and labeling across both countries (5). Consumer education coupled with accurate labeling would allow consumers to make more informed choices and control the demand for more sustainable seafood.

As more light is being shed on this issue, programs are being developed to help combat seafood mislabeling. From edible QR codes which diners can scan to download harvesting information about their fish, to ‘trip tickets’ allowing consumers to track their seafood from harvest to plate, these initiatives are helping raise consumer awareness. Through these programs and others, consumers can gain the power to influence stricter labeling standards for the future to help enhance traceability in the global seafood trade and to help further support truly sustainable fisheries.




  1. “Seafood Fraud: Overview.” 2012. Oceana. Retrieved November 17, 2013, from
  2. Carvalho, D. C., Neto, D. A., Brasil, B. S., & Oliveira, D. A. (2011). DNA barcoding unveils a high rate of mislabeling in a commercial freshwater catfish from Brazil. Mitochondrial DNA, 22(S1), 97-105.
  3. GAO, U. (2009). Seafood Fraud: FDA Program Changes and Better Collaboration Among Key Federal Agencies Could Improve Detection and Prevention.
  4. Hanner, R., Becker, S., Ivanova, N. V., & Steinke, D. (2011). FISH-BOL and seafood identification: Geographically dispersed case studies reveal systemic market substitution across Canada. Mitochondrial DNA, 22(S1), 106-122.
  5. Miller, D., Jessel, A., & Mariani, S. (2012). Seafood mislabeling: comparisons of two western European case studies assist in defining influencing factors, mechanisms and motives. Fish and fisheries, 13(3), 345-358.