The Wels Catfish has its native range throughout eastern and central Europe, with a small population in Sweden, where it is red listed as vulnerable. Previously we generated a draft catfish assembly, using linked read sequencing technology. We then employed genome resequencing via Illumina to conduct a population genomics study of Swedish catfish populations (published in Heredity). We have extended our study to European catish populations, including samples from the Czech Republic, Spain and France. This project will use whole genome sequencing with Illumina to investigate diversity within and differentiation between sampled river systems.