Influence of biological and environmental factors on nitrogenous extractives of the spurdog Squalus acanthias

The influence of sex, sexual maturity, feeding habits and season on the most important nitrogenous extractives in the muscle tissue of the spurdog Squalus acanthias L. of the southern North Sea has been studied. Feeding habits and sex have no influence, whereas the contents of -amino nitrogen, -alanine, glutamic acid and glycine decrease after sexual maturity. Only peptides are influenced by season; higher amounts occur in the spring/summer period.