In collaborative experiments with the National Research Institute of Far Seas Fisheries of Japan, genetic samples have been taken from broodstock yellowfin and their eggs and larvae to determine the amount of genetic variation in both adults and their offspring.  Novel genetic markers have been developed for yellowfin that provide the first direct evidence of Mendelian inheritance of nuclear DNA variants in a highly mobile, pelagic fish.  These markers have been used to analyze the spawning patterns of individual female yellowfin and to estimate the number of female fish contributing to individual spawning events.  Genetic sampling of broodstock, eggs, and larvae is ongoing.