
Fish fraud is widespread in markets around the world, and there are a growing number of tools to combat it, according to a new report published by the Food and Agriculture Organization of the United Nations (FAO).
“Food fraud in the fisheries and aquaculture sector,” produced by FAO through cooperation between its Fisheries and Aquaculture Division and the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, offers an incisive portrait of the complex field of fraud and a review of how novel analytical techniques can help detect it.
There is no official estimate of how prevalent fraud is in the US$195 billion global fisheries and aquaculture sector, but empirical studies suggest that 20% of the trade may be subject to some type of fraud, notably higher than for meat and fruits and vegetables, largely due to the vast diversity of species in the sector.
Fish fraud is defined in the report as “a deliberate practice intended to deceive others” and, depending on the type of deceit it can pose risks to biodiversity, human health or economic systems.
The main categories of fish fraud are:
- Adulteration (adding coloring to make tuna look fresher)
- Counterfeit (imitation shrimp made from starch-based compounds)
- Simulation (packaging surimi to seem like crab meat)
- Diversion (distributing legitimate products outside of their intended markets)
- Misbranding (such as incorrect claims about sustainability)
- Overrun (involving overfishing)
- Species substitution (selling tilapia as red snapper)
- Tampering and mislabeling (involving origins and even expiry dates)
- Theft
The report advocates harmonized labeling requirements, the mandatory inclusion of scientific names where possible, and better traceability systems. The use of advanced techniques ranging from enzyme-linked immunosorbent assay, stable isotope analysis and nuclear magnetic resonance can be effective, although not available to all, while portable X-ray fluorescence and machine-learning models are innovations that can aid regulation.
The evidence base
Although thousands of fish fraud studies have been carried out, demonstrating the widespread nature of the problem in every continent save Antarctica, there are no solid baseline studies to estimate its prevalence. The global scale of fish consumption, targeting more than 12,000 seafood species, the diversity of fraud types, and the lack of standardized regulatory or legal definitions of fraud, make global estimations difficult to obtain.
However, some studies suggest that up to 30% of seafood products may be mislabeled in restaurants, and the report cites cases from around the world, from ceviche stands in Latin America and seafood eateries in China to canned tuna products in the European Union. While as much as one-third of aquatic products sold in the United States may not be what is written on the packaging, less than 1% of imports are tested.
The human welfare risks of some seafood fraud are evident, as some fish pose risks when eaten raw, while re-freezing seafood increases the risk of bacterial growth. However, economic incentives are the most widespread driver of fish fraud.
Tools and initiatives
Given its complexity, identifying fish fraud is not straightforward, but the report goes into considerable detail about how advances in science can contribute to tackling fraud. A standard method to determine whether and how many times a seafood product has been frozen has so far proven elusive, but differences in the fatty-acid composition of wild and farmed fish may be used to detect fraud, as well as carbon and nitrogen ratios to determine the geographical origin of major commercial fish species.
Prevention and enforcement, with the active participation of the private sector, is critical to reduce and eventually eliminate fish and all food fraud. FAO and the Codex Alimentarius Commission are working on developing international standards to combat food fraud, while FAO through the Joint FAO/IAEA Centre offers technical support to Members that need to bolster their testing capacities.











