MORPHOLOGY AND ULTRASTRUCTURE OF THE REPRODUCTIVE-SYSTEM OF LEPEOPHTHEIRUS-SALMONIS (KROYER, 1837) (COPEPODA, CALIGIDAE)

The morphology, histology, ultrastructure, and development of the repr oductive system in Lepeophtheirus salmonis, a major pathogen of farmed salmon, are described using LM, TEM, and SEM. In both sexes the repro ductive structures are visible at the preadult stage, but they do not mature until the adult stage. The female reproductive system consists of a pair of ovaries, oviducts, cement glands, and a single receptacul um seminis. Various stages of oogenesis are discernible within the ova ries and oviducts of preadult II and adult females. Oogonia divide to primary oocytes which pass into the oviduct and undergo vitellogenesis . The reproductive system of male L. salmonis consists of a pair of te stes, vasa deferentia, spermatophore sacs, and cement glands. Various stages of spermatogenesis are discernible within the testes of preadul t and adult males. Degenerating spermatocytes in the testes form ''A'' globules which pass down the vasa deferentia and fuse to form the inn er secretion of the spermatophore, which later forms the spermatophore tube and fills the copulatory duct of the female. Several features of the reproductive system suggest that adult female L. salmonis are mon ogamous, while adult males are polygamous.