Reference databases and taxonomic assignment
Taxonomic assignment was performed using the ecotag function of
OBItools package. For both Teleo and MiFish markers,
taxonomic assignments were made using a comprehensive reference database
of 12S rRNA barcodes for over 90% French Guiana’s freshwater fish
(Brosse et al., submitted). MG2 sequences were obtained from BOLD
(Ratnasingham & Hebert, 2007) through the Gui-Bol project (Barcoding
Guianese fishes, see Papa et al. 2021). To enable meaningful comparisons
of fish assemblages across survey methods, we only kept assignments
reaching species-level resolution and showing ≥97% sequence identity
with the reference database. Sequences below this threshold were
discarded, and assignments were further refined to exclude taxa never
documented in the Approuague River systems, based on Le Bail (2012).