EXECUTIVE SUMMARY

In 1997, field studies of the endangered Hawaiian monk seal (Monachus schauinslandi) were conducted at all of its main reproductive sites in the Northwestern Hawaiian Islands. These studies provide information necessary to evaluate (1) the status and trends of monk seal populations, (2) natural history traits such as survival, reproduction, growth, behavior, and feeding habits, and (3) the success of various activities designed to facilitate population growth. Results of these studies are best described on a site-bysite basis, and the information presented in this document is organized accordingly. Pooled site-specific data, however, provide useful indices of the status and trends of the whole species, including the total number of pups at the main reproductive sites, the total of the site-specific mean beach counts, and the size composition of the seals observed during the counts (Fig. 1). Since 1983, the number of pups born at the main reproductive sites (excluding Midway Atoll) has been highly variable, and the variability has been largely determined by the number born at French Frigate Shoals (Fig. 1a), the largest subpopulation. In 1997, 201 pups were counted at these sites, 97 of which were born at French Frigate Shoals. Mean beach counts, excluding pups, from the main reproductive sites (again, excluding Midway Atoll) totaled 373 seals and have remained essentially unchanged since 1993 (Fig. 1b). Since the mid 1980s, adults have comprised a growing portion of the animals counted (Fig. 1c) and, in 1997, the composition of the counts remained largely skewed towards adults. This shift in composition bodes poorly for reproduction in the near future if older adult females are not replaced by young females reaching reproductive age. The overall impact from this shift in composition will be determined by the magnitude of its change and the length of time that the resulting skewed distribution persists, neither of which can be reliably predicted at this time. High mortality of immature seals appears to be a major factor leading to the shift in composition, particularly a