Offspring from matings between divergent populations can often show reduced fitness due to genetic incompatibilities between the parents. Using the tidepool copepod Tigriopus californicus, we screened hundreds of hybrid male individuals that differed in their level of fertility. We used whole-genome sequencing and QTL statistical analysis to identity regions of the genome that are strongly associated with the tendency to be sterile in these adult male copepod. Data in this project consists of four biological samples, with each sample being a pool of ~75-100 copepods from which genomic DNA was extracted for genome sequencing.