The Hawaiian monk seal : abundance, estimation, patterns in survival, and habitat issues

This thesis addresses Hawaiian monk seal abundance estimation, patterns in survival, and habitat issues. Closed capture-recapture abundance estimation methods were found typically to yield negatively-biased estimates, suggesting the influence of individual capture heterogeneity. Through analysis of discovery curves, a criterion was derived to determine whether total enumeration had been accomplished at a given site and year. Age-specific survival rates of monk seals were relatively low from weaning to age 2 yr, intermediate to age 4 yr, then relatively high rates were sustained until age 17 yr, following which senescence was detected. Temporal trends in survival among subpopulations suggest regional structuring and connectedness within the archipelago. Survival rates were analysed in relation to a North Pacific oceanographic feature hypothesized to variably deliver relatively productive waters into monk seal foraging habitat. For young monk seals at themost northerly atolls, survival was lower when the front remained further north. The relationship was strongest following a one- or two-year lag. The first surveys of the main Hawaiian Islands (MHI) found a minimum 45 seals in 2000, and 52 in 2001. MHI births have evidently increased since the mid-1990s, and weaned pups in the MHI are larger than those in the species core range, the Northwestern Hawaiian Islands (NWHI). Seals may have recently re-colonised the MHI, which were very likely part of their historic range. Most NWHI are low-lying and therefore potentially vulnerable to increasing global average sea level. The potential for significant habitat loss due to sea-level rise was revealed under a range of passive flooding scenarios. Insights gained from syntheses of long-term Hawaiian monk seal datasets, augmented with new field studies, have altered some perspectives and priorities for conservation of the species.EThOS - Electronic Theses Online ServiceGBUnited Kingdo