AbstractComponent acid analyses have been carried out on body And liver oils from the Cape John Dory (Z. capensisC. and V.) in fat or thin condition. In both liver and body, increase in fat content of the fish results in an increase in the content of the highly unsaturated C20, C22and C,14acids in the oil, and a decrease in the degree of average unsaturation of the C18and C26acids. In the liver the latter effect is dominant and therefore the iodine value of the liver oil tends to decrease with increase in fat content of fish: in the body, however, the former effect prevails and increase in iodine value of the body oil results.As in other species with a diffuse system of fat storage, the liver oil in distinguished from the body oil by its higher content of C18unsaturated acids, and by a decreased content of the more highly unsaturated C20and C23acids. The distinction between the liver and body oils is not as marked as is usual in such species, however, and this is related to the comparatively high degree of fat storage in the liver of the John Dory.