Fine structure, motility and cryopreservation of spotted sea bass, Lateolabrax maculatus (Moronidae, Teleostei), spermatozoa

Both transmission- and scanning electron microscopy were used to investigate the fine structure of spermatozoa of the spotted sea bass (Lateolabrax maculatus). The spermatozoa are of the ect-aquasperm type, with a head lacking acrosome, midpiece, and tail regions. The centriolar complex is situated outside the nuclear fossa and the flagellum is parallel to the base of the nucleus. A midpiece, containing four mitochondria, extends from the posterior end of the nucleus and encircles the root of the flagellum. A pyramidal basal foot projects laterally at right angles from the midregion of the basal body. The effects of osmolality and pH on activation of spotted sea bass sperm motility were examined and compared with those of the moronids Dicentrarchus labrax and Morone saxatilis. A simple method of cryopreservation semen was also demonstrated. This study contributes to existing knowledge of comparative sperm biology and may facilitate breeding of this economically important species.