biostudies-literatureGaillard MEuropean Regional Development Fund15985https://www.ebi.ac.uk/biostudies/studies/S-EPMC9512919biostudies-literatureUnknown12(1)Alizarin detection in fish fins is extensively employed because it is easy to use. However, in eels, the eelGFP fluorescent protein may impede the detection of the fluorescent markers in the eel tissues. The study tests the effectiveness of three of the most up-to-date alizarin-detecting technologies on the living body and fins of European glass eels (Anguilla anguilla L.). The findings demonstrated that the control group had a high autofluorescence at alizarin and eelGFP maxima bands. With fluorescence reflectance imaging (FRI), the eel living body autofluorescence impeded the detection of the marked eels. In contrast with experimental excitation-emission-matrix (EEM) fluorescence analyses, 99% of the marked eels were correctly assigned to their group from fluorescence analyses of their fScientific reportsNew insights into detecting alizarin from autofluorescence in marked glass eels.PMC95129193536310Parlanti EGaillard MDaverat FGenevois CBoutry SSourzac MCouillaud FRigaud CfalseNew insights into detecting alizarin from autofluorescence in marked glass eels.Alizarin detection in fish fins is extensively employed because it is easy to use. However, in eels, the eelGFP fluorescent protein may impede the detection of the fluorescent markers in the eel tissues. The study tests the effectiveness of three of the most up-to-date alizarin-detecting technologies on the living body and fins of European glass eels (Anguilla anguilla L.). The findings demonstrated that the control group had a high autofluorescence at alizarin and eelGFP maxima bands. With fluorescence reflectance imaging (FRI), the eel living body autofluorescence impeded the detection of the marked eels. In contrast with experimental excitation-emission-matrix (EEM) fluorescence analyses, 99% of the marked eels were correctly assigned to their group from fluorescence analyses of their f2022-01-01T00:00:00Z2022 Sep2025-04-22T06:22:40.849Z2025-04-05T21:41:54.665ZS-EPMC95129193616344210.1038/s41598-022-18440-0