Project description
Austrian fish production falls far short of meeting the country’s demand for fish (fish dependence day: 30 January 2024). The fish consumed in Austria therefore comes predominantly from foreign production (partly state-subsidised), including the production and farming of freshwater fish. As consumers prefer fish from domestic production, it must be possible to verify the declared origin of the fish in order to detect false declarations regarding the origin of fish sold in Austria and to maintain and build consumer confidence. Verification of the declared origin should be carried out on the product itself, so as, on the one hand, not to limit checks solely to accompanying documents and, on the other hand, to enable targeted, in-depth checks (such as delivery notes and supply chain analysis) to be initiated in the event of suspicious analysis results.
A common method for verifying the declared origin of foodstuffs is isotope analysis (IRMS: isotope ratio mass spectrometry). This method has already been successfully applied to a wide variety of (food) matrices. The differentiation of various geographical origins of fish has also been described on several occasions. This analytical approach would open up possibilities for identifying imported fish – for example, from Turkey – that is falsely labelled as domestic fish, thereby maintaining consumer confidence and protecting the domestic aquaculture sector from reputational and economic losses.
The aim of the project is to evaluate the possibilities for distinguishing between trout from Austrian fish farms and those from Turkey using stable isotope analysis (IRMS). To achieve this objective, the plan is to develop a step-by-step approach to geographical differentiation (selected fish analysis, statistical methods, seasonal variation, etc.) by applying stable isotope analysis to verify the declared origin of the trout. Subsequently, the data could be further expanded and, where necessary, combined with other analytical methods (e.g. elemental analysis, Sr analysis) to achieve a higher spatial/geographical resolution.
Benefits of the project
The aim of this project is to lay the foundations for the use of stable isotope analysis in the routine verification of the geographical origin of trout sold on the Austrian market. To this end, the project plans to analyse geolocated reference samples from selected trout farming sites in Austria. The isotopic pattern of the elements in animal biomass (fish flesh, fat) depends on factors such as feed and water; the latter, in turn, depends on geography and climate (altitude, prevailing wind direction = precipitation transport, temperature, etc.) and geology. In this specific case, the aim is to distinguish Austrian trout from those originating in Turkey.
It is expected that the isotope patterns will enable a clear distinction to be made between Austrian and Turkish trout. The results are to be documented in a database, which can serve as an initial basis for future monitoring. In addition, the method will be validated in terms of reproducibility and accuracy.
Project details
Project title: Evaluation of methods for tracing the origin of Austrian trout and distinguishing them from trout from Turkey using isotope analysis
Project acronym: ISOTOP-TROUT
Project lead: AGES
AGES Project Manager: Gerhard Liftinger
Project partner: Austrian Association for Fisheries and Aquaculture
Scientific support: Federal Office for Water Management
Funding: EMFAF
Project duration: 1 February 2026 – 31 January 2028
Last updated: 25.06.2026
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