ZSL at CITES CoP - Anguillid eels

Anguillid eels

Eel species are being challenged by a range of pressures, including habitat loss, barriers to migration and exploitation, with conservation hampered by incomplete knowledge of their remarkable life-histories.

A document put forward at the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) calls to improve our knowledge of these incredible animals and minimise the risk of trade detrimentally impacting them.

An eel. Picture: David Curnick
European Eel

There is growing concern relating to the recruitment, population and escapement of the 16 species of catadromous eels of the family Anguillidae. Anguillids breed in the ocean and feed and grow in continental coastal and freshwater bodies, and as such they link both marine and inland waters and can act valuable indicator and integrator of the well-being of aquatic ecosystems. However, incomplete knowledge of their remarkable life-histories hampers stock assessment, management and conservation. 

These species are exposed to a suite of pressures that include habitat loss/modification, migration barriers, pollution, parasitism, exploitation, and fluctuating oceanic conditions that likely have cumulative, synergistic and/or regionally variable impacts, even within species.

Of the 13 species assessed using the IUCN Red List Categories and Criteria, four were listed as ‘Threatened’ (Vulnerable, Endangered or Critically Endangered); four were Near Threatened, three were Data Deficient and two were deemed Least Concern. The northern temperate species of the Endangered Japanese and American eels and the Critically Endangered European eel have shown marked declines in recruitment, population and escapement over the past 30-40 years. Equally concerning is our poor understanding of the tropical species – primarily listed as Near Threatened or Data Deficient  – some of which, in addition to existing threats, are beginning to be exploited, both legally and illegally, in increasing numbers due to the decline in temperate species.

Eels in a barrel
Japanese Eel

The European eel is arguably the species of greatest concern at present due to the Critically Endangered listing, and a number of measures have been implemented to improve management and conservation over the past 10 years. European Union legislation (EU Regulation 1100/2007 ) was developed in 2007 to ensure all member states had created Eel Management Plans to address these declines.

In addition to the Regulation, the species was listed in Appendix II of CITES in 2007 due to concerns over the impact international trade was having on European eel stocks. This was in an attempt to ensure that all trade in the species was sustainable. The listing came into effect in March 2009, however, in December 2010 the EU banned all imports and exports of live and processed European eel as it was not felt they could assure that trade would not be detrimental to the species. Since this time, the EU has taken steps to put measures into place to assess the impact of trade on the European eel, most recently through a workshop to define criteria for determining an NDF European eels . Additionally, the species has also been listed in Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS) and co-operative actions on all threats, including unsustainable and illegal fisheries are being explored.

Kabayaki - gutted fillets of eel
Grilled Eel

Despite the EU export ban, there is a still a demand for European eel in key import and consumer markets in East Asia. Some of the demand has been met through the opening and/or expansion of non-EU European eel markets in North Africa and through increased exploitation and export of other species, particularly A. rostrata and A. bicolor, however, there is concern that a significant black market for A. anguilla exists. Indeed, there is concern relating to illegal exploitation and trade in all species of anguillids, and as most trade relates to juvenile glass eels, species identification is hugely problematic. Seizures of illegally exported European eels do occur but they are believed to be intercepting only a small proportion of the illegal trade. 

More broadly, there are fundamental issues relating to the collection of fisheries data and it has been repeatedly stated, for the European eel, that it is often incomplete and/or of variable quality, and this is true of most other anguillid fisheries, and the associated trade. There have been calls for the development of standards to improve data quality and coverage and management of legal fisheries more generally and exploring these options would be hugely valuable. Improved compliance and enforcement of national and international legislation would strengthen this management. Additionally, chains of custody are often extended and complex and multi-national which can complicate traceability, and measures to improve transparency of these would be hugely valuable.

Ultimately, the understanding of the biology and population dynamics of these species remains poor, and this especially applies to the tropical species.


…allow for more information and data to be gathered on population abundance and exploitation, and to facilitate the development of recommendations on the sustainable trade of all Anguilla species...

ZSL briefing note on Anguillid eels

PDF icon ZSL Briefing Note - Anguillid Eels.pdf (397.91 KB) (397.91 KB)