REPRODUCTION IN THE MALE CAPE FUR-SEAL ARCTOCEPHALUS-PUSILLUS-PUSILLUS - AGE AT PUBERTY AND ANNUAL CYCLE OF THE TESTIS

Seasonal changes in the reproductive anatomy and histology of the male Cape fur seal Arctocephalus pusillus pusillus were examined. Studies were based on 99 specimens collected between Algoa Bay on the south-ea st coast of South Africa, and Cape Frio, Namibia, during 1974 to 1990. Reproductive organs are briefly described. The presence of sperm in t he seminiferous and epididymal tubules indicates that males attain pub erty between 3 and 4 years of age. Quantitative measurements of testis weight, testis volume, and the diameter of the seminiferous and epidi dymal tubules were analysed on a monthly basis and spermatogenesis doc umented. Although some males may remain in breeding condition until Ma rch, the absence of spermatozoa in the epididymis during February to J une, when mean testis mass and mean tubule diameter reached a minimum, clearly showed reproductive quiescence following the rut. Four stages of spermatogenesis were observed: (1) inactive (February/March-June); (2) early spermatogenesis (July); (3) late spermatogenesis (July/Augu st-December/January); and (4) epithelial regression (February-June). I ndividual variation between males, possibly differences in social stat us and body condition, may influence the duration of spermatogenesis, hence the overlap in duration between epithelial regression and inacti vity. It appears that photoperiod may act as an obligatory proximate f actor initiating spermatogenesis 3-4 months before the relatively shor t breeding season from November to December.