Studies on blood proteins of mackerel

1. 14 samples of mackerel, about 1800 specimens, from the North Sea and the Norwegian Coast were analysed by agar gel electrophoresis (hemoglobins) and combined starch and agar gel electrophoresis (serum proteins and serum esterase). 2. Hemoglobin variations related to ontogeny appeared during the first year of the mackerel's life. In mackerel one year and older normally one strong hemoglobin component occurred. Two strong components were observed in some specimens (probably heterozygotes) but too infrequently to be used for studies on population units. 3. In the serum proteins were found extensive variations, but the greater part of the variations occurred in very weak bands, or the observed phenotypes were somewhat unstable. Normally one transferrin band was seen, but also a double band pattern (probably heterozygote) were observed although too infrequently to be used in studies of population units. 4. Five esterase components could be clearly distinguished, and a few more were indicated. Each of the components seemed to be controlled by one gene in a series of polyalleles, although some samples showed a significant excess of observed homozygotes according to this theory. 5. No significant variations in gene frequencies between the samples were found. The results also were approximately in accordance with corresponding results from the southern North Sea and the areas south of the British Islands