SEASONAL-CHANGES IN HEMOCYTES AND SERUM DEFENSE FACTORS IN THE BLUE MUSSEL MYTILUS-GALLOPROVINCIALIS

Hemolymph characteristics were examined in experimentally cultured blu e mussels Mytilus galloprovincialis Lmk. from 2 locations in the Ria d e Vigo (NW Spain). The highest protein, lysozyme and agglutinin values were found in July. The increase of agranular hemocytes and the decre ase of granular blood cells in April was associated with parasitism by Mytilicola intestinalis. No linkage was found between the number of c irculating hemocytes and hemolymph component (lysozyme, agglutinins an d proteins) concentrations with parasitism. It is suggested that the n umber of circulating hemocytes, lysozyme and proteins levels and agglu tination titer were related to the reproductive cycle and varied accor ding to the location of mussels.