title: Reproductive seasonality of the male Florida gar, Lepisosteus platyrhincus.
abstract: The objective of this study was to characterize the reproductive seasonality of a wild population of male Florida gar, Lepisosteus platyrhincus. We measured the gonadosomatic index, reproductive stage of the testes, seminiferous tubule area, and plasma concentrations of testosterone and 11-ketotestosterone for each fish. A seasonal pattern was observed in the reproduction of male gar. Following a quiescent period in the summer, there was an increase in plasma testosterone concentration during the fall, which was associated with the onset of active spermatogenesis as indicated by an increase in seminiferous tubule area and gonadosomatic index. Plasma concentrations of 11-ketotestosterone remained basal during the summer and winter and then increased during the early spring. These data, taken together with data from female gar collected in a parallel study by our lab, suggest that spawning occurred during the early spring (February-March), followed by a general decrease in reproductive parameters to summer levels. Recognizing that peaks of hormone concentrations and spawning period could vary with annual seasonal variation, this study is important because it is the first characterization of the seasonal morphological and endocrinological reproductive pattern in a holostean species. Furthermore, it increases our understanding of the reproductive biology of semitropical fishes.
authors.affiliation: Department of Zoology, University of Florida, 223 Bartram Hall, Gainesville, FL 32611, USA. eforlando@smcm.edu
authors.forename: Edward F
authors.initials: EF
authors.lastname: Orlando
authors.forename: Gerald A
authors.initials: GA
authors.lastname: Binczik
authors.forename: Peter
authors.initials: P
authors.lastname: Thomas
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Guillette
mesh_terms: D000818:Animals; D005260:Female; D005399:Fishes / Q000502:physiology*; D005431:Florida; D008297:Male; D011863:Radioimmunoassay; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D012671:Seminiferous Tubules / Q000502:physiology; D012726:Sexual Behavior, Animal / Q000502:physiology; D013737:Testis / Q000502:physiology; D013739:Testosterone / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D013739:Testosterone; C003600:11-ketotestosterone