ANNUAL REPRODUCTIVE-CYCLE OF THE FEMALE HAWAIIAN MONK SEAL (MONACHUS-SCHAUINSLANDI)

The annual reproductive cycle is described for the adult female Hawaii an monk seal (Monachus schauinslandi) from data collected at Laysan Is land (1982-1991) and Lisianski Island (1982-1983) in the Northwestern Hawaiian Islands. Pupping, lactation, weaning, and molting were direct ly observed, while mating was rarely observed and was, therefore, infe rred from the occurrence of mounting injuries and from adult male and female association patterns. Pooled birth rates during the study perio d were 0.544 for all adult-sized females and 0.675 for females parous in earlier years. For parturient females, pupping peaked in late March and early April, weaning in May, mounting injuries in May and June, a nd molting in July. For non-parturient females, the median mounting in jury and molting dates occurred 17 and 28 days earlier, respectively. Pupping date set the timing of subsequent events in the annual cycle, but the timing of those events was adjusted by loss of the pup or poor physical condition of the female. Individual pupping patterns varied widely. The mean interval for births in consecutive years was 381 days ; females that pupped in consecutive years gave birth later each seaso n. Conversely, females who skipped a year or more gave birth earlier t heir next pupping season.