Attendance to the X SIBIC congress
Last June the Tenth Congress of the Iberian Society of Ichthyology (SIBIC 2024) was held under the slogan ‘FishesForFuture’. We presented the results of the TRADAPTOMICS project on the genomic diversity of brown trout populations in the upper reaches of the River Ter, in the Eastern Pyrenees.
Brown trout populations in the Iberian Peninsula have undergone a change in their native gene pool due to the introduction of non-native specimens from central European stocks. Our analyses in the headwaters of the Ter and its tributary the Freser rivers show that this effect is detectable along the 40 chromosomes of the brown trout and that it is mainly present in the populations in the main stretches of the rivers.
Populations in tributaries tend to be less affected or still maintain native populations. Genomic analyses also show that these populations have been declining for more than 100 generations and that the decline has accelerated since the second half of the last century. Releases of non-native individuals are being reduced or stopped, but the spread of naturalized individuals or their hybrid offspring is now contributing to the loss of native trout stocks throughout the river basin.
This observation also warns us that while restoring connectivity by removing barriers in these rivers can be a great help in increasing fish populations, we need to consider the risk they pose to the spread of introduced individuals or their offspring into areas still inhabited by native populations.
Results of the TRADAPTOMICS Project, RTI2018-095760-B-C21 funded by the Spanish MICIU/AEI /10.13039/501100011033/ and European Regional Development Fund (ERDF). These results are the basis for the CONSIBEROTROMICS project.