Determining the potential of otolith and tissue microchemistry for the traceability of glass eels
Project duration: 07/2017 – 05/2019 Project partners: BOKU Vienna, University of Southampton Contact: Florian Stein, Director of Scientific Operations, f.stein@SustainableEelGroup.org
Export of European eel from and into the EU is suspended since December 2010 and EU regulations set a clear framework and therefore demands the identification of origin and traceability of all live eels. Two major factors impede the traceability of live traded European glass eels across Europe and beyond: (1) The species range of A. anguilla exceeds the borders of European Union and consequently eels of different origin cannot be distinguished by genetics. (2) Illegal trade of glass eel from Europe to Asia has recently been identified as one of the potential major threats for the species survival and is estimated to account for 30-50% of the declared European glass eel catches. In addition, countries neighboring the EU, increasingly export European eels since 2010. It is uncertain if these exports from non-EU countries originate from their territories, or if shipments include eels of EU origin.
We want to evaluate if future spatial differentiation of eels’ provenance can be achieved by stable isotope analyses (otoliths and muscle tissue) and fatty acid profiles. These measures have the potential to determine the eels’ provenance down to the estuary level. Preliminary studies determined otolith elemental ratios via LA-ICP-MS. Although elemental fingerprints were year-specific, variation among seasons did not hinder spatial discrimination.
We postulate that the chemical signatures of otolith increments and muscle tissues will vary distinguishably according to the estuarine catchment environment (e.g. geology, agricultural use, pollutants) and that these variations can be detected by non-parametric discriminant analysis or Bayesian statistics. In accordance with eel regulation 1100/2007 and the “Action Plan against wildlife trafficking”, the library, containing the elemental fingerprints of the major glass eel catch areas in Europe and North Africa, would be a valuable support for the counteraction of the illegal trade in eels.