A BLOOD GROUP SYSTEM FOR SPINY DOGFISH, SQUALUS ACANTHIAS L

¹ U. S. Bureau of Commercial Fisheries Biological Laboratory, Boothbay Harbor, Maine

1. An erythrocyte antigen system of dogfish, Squalus acanthias, has been recognized and described with a progression of serological procedures including isoagglutination, antiserum absorption and isoimmunization. This system, the "S" blood group system, contains at least two antigens, "S₁" and "S₂." Individual fish may possess both, either or neither of the antigens, being of blood groups (types) S₁,S_2, S₁, S₂ or S₀, respectively. Reagents specific for the antigens have been prepared from normal dogfish sera and absorbed rabbit antiserum, for quantitative studies of blood group frequencies in dogfish from different geographic areas. Fish sampled thus far in the Gulf of Maine (138 individuals) have the following frequencies: S₁S₂—1.4%, S₁—66.7%, S₂—0.7%, and S₀—31.2%. Blood groups of females and unborn pups are compatible with a simple genetic hypothesis of three alleles, S¹, S² and S⁰, controlling the system.

2. The definitive nature of this system in Squalus promises potentially profitable immunogenetic investigations of other elasmobranchs, including the larger shark species. Blood group frequencies can be used in determining the degree of reproductive isolation of populations and may provide information about migrations of fishes.