Abstract
Lysozyme activity in seven organs of the mussel Mytilus edulis was determined to evaluate seasonal variation. Although no correlation was detected between lysozyme activity of any organ and its constituents, two groups of organs showed positive correlation of variation in lysozyme activity with season. One group included the gill, mantle, body fluid, and foot, while the other the mid-gut gland, gonad, and adductor muscle. In the mussel lysozyme may be essential to defense against exogenous and endogenous bacteria in the two groups, respectively.
