Most freshwater eels eaten worldwide are from threatened species, study finds
Gaby Clark
scientific editor
Robert Egan
associate editor
Professor Kenzo Kaifu and Research Fellow Hiromi Shiraishi of Chuo University, together with Professor Yu-Shan Han of National Taiwan University, conducted the world's first quantitative study to reveal the global consumption structure of freshwater eels (genus Anguilla).
The research team combined DNA barcoding of eel products—purchased from retail stores and restaurants worldwide—with production and trade statistics to estimate species composition at the global level. Their findings were in Scientific Reports on August 15, 2025.
Fishery resources are vital to humanity but are inherently vulnerable as they depend on natural ecosystems. Strong demand in certain regions can lead to overexploitation of resources elsewhere, creating serious global management challenges.
Freshwater eels (Anguilla spp.), comprising 16 species worldwide, are among the most valuable fishery resources. Glass eels for aquaculture fetch extremely high prices in international trade, which has led to poaching, smuggling, and other illegal activities. Of the 12 Anguilla species assessed by the IUCN, 10 are listed as threatened or near threatened due to habitat degradation, overfishing, climate change, and disease.
Demand shifts between species and regions in response to declines and trade restrictions—for example, decreased catches of Japanese glass eels increased demand for European eels, and once European eels were listed under CITES, demand shifted again toward Southeast Asia and the Americas.
Although DNA barcoding enables precise identification of eel species in processed products, global-scale consumption patterns could not be determined without integrating this with distribution volumes. This study is the first to reveal, on a worldwide scale, "which eel species are being consumed, and where."
Between 2023 and 2025, 282 eel samples were collected from retail outlets and restaurants in 26 cities across 11 countries/regions. DNA barcoding revealed four species: American eel (Anguilla rostrata), Japanese eel (A. japonica), European eel (A. anguilla), and Indonesian shortfin eel (A. bicolor).
When weighted by national distribution volumes estimated from production and trade statistics, the results showed:
- According to FAO statistics: American eel 75.3%, Japanese eel 18.0%, European eel 6.7%, Indonesian shortfin eel 0.02%.
- According to "Informal Consultation" Statistics from East Asia: American eel 52.7%, Japanese eel 43.5%, European eel 3.6%, Indonesian shortfin eel 0.2%.
Regardless of the data source (FAO or the Informal Consultation), over 99% of global consumption consisted of three threatened species (American, Japanese, and European eels), with the American eel being the most consumed species worldwide. East Asia emerged as the global center of eel consumption, driven by cultural preferences and purchasing power. For more information about the Informal Consultation, please see the text box on the next page.
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National eel distribution volumes The upper map is based on FAO statistics, while the lower map is based on figures reported by the East Asian "Informal Consultation" statistics. The two datasets differ greatly in reported aquaculture production from China, resulting in different country rankings for distribution volumes. Note that the colours representing distribution volumes vary between the two maps. Grey indicates countries/regions with no available data. Regardless of the data source, East Asia accounts for the majority of global eel distribution. Credit: Created by Professor Kenzo Kaifu and Research Fellow Hiromi Shiraishi, Chuo University -
Species composition of eels consumed worldwide The left chart is based on FAO statistics, and the right chart is based on unofficial regional statistics. In both cases, the most widely consumed eel is the American eel, followed by the Japanese eel and the European eel. For the European eel, estimates were adjusted by accounting for consumption within Europe. Credit: Created by Professor Kenzo Kaifu and Research Fellow Hiromi Shiraishi, Chuo University -
Sampling locations and species composition by country Green dots indicate the cities where eel samples were collected. The pie charts show the species composition in 11 countries/regions: [Navy blue] American eel, [Green] European eel, [Red] Japanese eel, [Light blue] Indonesian shortfin eel. European eels were detected only in Japan and China, while Indonesian shortfin eels were found only in Hong Kong. The "Whole samples" chart in the lower left shows the simple species composition without weighting by distribution volume. The reason why European eels were not detected in Europe is that only products prepared in the Japanese style, such as sushi and kabayaki, were sampled. This sampling bias was mitigated by assuming that eel production in countries where European eels are distributed consisted of European eel, and incorporating this assumption into the subsequent calculations. Credit: Created by Professor Kenzo Kaifu and Research Fellow Hiromi Shiraishi, Chuo University
The Informal Consultation, formally named the Informal Consultation on International Cooperation for Conservation and Management of Japanese Eel Stock and Other Relevant Eel Species, is composed of China, Japan, South Korea, and Taiwan.
Each year, governments, eel farmers, and experts meet to collect and publish data on eel catches and aquaculture production. Although these are "official" statistics reported by governments, the aquaculture production figures published by the Informal Consultation differ greatly from those released by the FAO. This discrepancy makes it difficult to accurately understand the reality of global eel consumption.
This study is the first to provide a quantitative picture of global eel consumption by species. It highlights that the vast majority of eels consumed worldwide belong to threatened species, while also exposing serious inconsistencies in production and trade statistics.
The findings demonstrate the urgent need to improve the accuracy of global aquaculture and trade data and suggest that sustainable use of eel resources is currently extremely difficult. Future work should expand monitoring to underrepresented regions and species while addressing weaknesses in data reporting systems.
More information: Kenzo Kaifu et al, Global consumption of threatened freshwater eels revealed by integrating DNA barcoding, production data, and trade statistics, Scientific Reports (2025).
Journal information: Scientific Reports
Provided by Chuo University
