Composition of the Hawaiian Monk Seal Population at Kure Atoll, 1990

Abstract

Population recovery-related management actions have been taken to rebuild the endangered Hawaiian monk seal (Monachus schauinslandi Matschie) colony at Kure Atoll in the Northwestern Hawaiian Islands since 1981. In 1990, composition of the Kure population was determined by a combination of methods to identify all seals using the atoll. The resident 1990 population included 75 seals, and an increasing trend in the mean annual beach count of seals over the last decade is apparent. Two major changes have occurred in the population since 1985. A shift in the adult sex ratio (males/females), from 2.7: 1 to 0.8: 1, has developed and appears to be due to both adult male losses and increased recruitment of females. Also, the declining trend in births apparent between 1981 and 1986 has been reversed. These findings suggest cause for optimism for the continued growth of this population.