84 I\ToRMATIoN AND Tecrwolocv Rnponr I Age afldseasonanty in sper:matogenesis of Florida Manatees by Patricia Hernandezl University of South Florida Depangnentof BiologY Tampa, Florida 33620 John E. ReYnolds, trI Eckerd College Department of Biology and Marine Science 4200 54th Avenue South St. Petersburg, Florida 3371I Helene Mars^. James Cook UniversitY Department of Tropical Environment Studiesand Geography Townsville, Queenslnnd 481I Australia and Miriam Marmontel2 University of Florida Department of Wildlife and Range Sciences Gainesville, Florida 326I I Abstract. A histological study of the testes andepididymides of the Florida manatee (Trichechus numatuslatirostris) wasmade to assess reproductive status. Testes or epididymides of 67 animals were examined for presence and abundance of sperm. In addition,qualitativeand quantitative examinations of theseminiferous tubules from 3l manatees, ranging in length from 98 to 320 cm (total length), revealed l0 stages in thespermatogenic cycle. Theshortest manatee in whichspermiogenesis occurred was a 237-cm-long, 2-year-old. Males as short as 252cm had fully spermatogenic testes, and one 255-cmlong individual was 2-3 years old. Spermatogenesis was not continuous and was significantly uff..t d by season. In winter (December through February), sperrn were found in either th'e testes oi epididymides of only l3Toof the recovered manatees thatmeasured 241to 280cm, and rPresent address: Museum of Comparative Zoology' Harvard University, 26 OxfordStreet, Cambridge' Mass. 02132' 2 Present address: Projeto Mamirua, Caixa Postal 0001, 69470-000 Tef6 AM. Brazil.