Relative to many highly migratory fishes, striped marlin, Kajikia audax, exhibit considerable stock structure. Five genetically distinct striped marlin stocks have been resolved throughout the Pacific and Indian oceans, but central North Pacific stock composition remains unclear. Genetic evidence from some studies indicates that central North Pacific striped marlin are part of a greater North Pacific stock, which includes individuals from Japan, Taiwan, Hawaii, and California. However, the presence of an additional central North Pacific stock has been suggested by two recent studies, albeit with relatively limited statistical power. The goals of this research are to 1) use genetics to validate the presence of a second stock in the central North Pacific and 2) examine the relative frequency of the two stocks over time. Striped marlin sampled from the Hawaii-based pelagic longline fishery will undergo genotyping-by-sequencing and the data will be used to supplement existing data to validate the presence of a separate central North Pacific stock. If the second stock is resolved, a genetic marker panel comprised of those loci with the highest power to discriminate the two stocks will be developed. Individuals of known size and reproductive condition collected from the central North Pacific over the course of one year will be assigned to one of the two stocks based on their genotype. Through intensive temporal sampling, this study will contribute a better understanding of central North Pacific striped marlin stock dynamics and represents the first investigation into the fine-scale stock composition of a highly migratory species fishery.