tary diet. For analysis, all fish from a group were taken out of the cage, analyzed and returned for future use. The crosses performed are listed in Table 1. In part of the experiments, the same parent (male or female) was mated to several individuals of the other gender (see Table 1). An additional cross was done between a Showa male and a Sanke female (Fig. la) to produce a large F1 segregating family for the association study.