Graduation Year


Document Type




Degree Name

Master of Science (M.S.)

Degree Granting Department

Marine Science

Major Professor

Norman J. Blake

Committee Member

Thomas L. Hopkins

Committee Member

Harold J. Humm


Lytechinus variegatus (Lamarck, 1916) is a sea urchin inhabiting shallow sub-littoral environments from Beaufort, North Carolina to southern Brazil. Although it has been collected extensively for embryological material in the southeastern United States (Harvey, 1956; Brookbank, 1968). there have been relatively few studies of its reproduction. Gonad indices were used to follow its annual reproductive cycle at Bermuda and Miami (Moore et al., 1963; Moore and Lopez, 1972), while elsewhere, only observations of spawn- ing have been reported (Boolootian, 1966).

In the Anclote estuary near Tarpon Springs, Florida, Lytechinus is the most conspicuous of the macroepibenthic invertebrates, and where requisite environmental conditions are satisfied, adults are found in relatively large numbers. Accordingly, an investigation was initiated to provide information on the reproductive cycle of this species along the west coast of Florida. Because Lytechinus occupies a variety of habitats in the Anclote estuary, one aspect of the study was to determine variability in reproductive activities associated with environmental heterogeneity. Additionally, reproduction was followed histologically so that gametogenesis, previously undescribed in Lytechinus, could be related to patterns of gonad growth. Finally, latitudinal reproductive variability was examined by com- paring observed reproductive phenomena of Lytechinus at Anclote with those described for geographically distant populations.