Modelling pinniped abundance and distribution by combining counts at terrestrial sites and in-water sightings

摘要: Abstract Pinnipeds are commonly monitored using aerial photographic surveys at land- or ice-based sites, where animals come ashore for resting, pupping, molting, and to avoid predators. Although these counts form the basis monitoring population change over time, they do not provide information regarding occur in water, which is often of management conservation interest. In this study, we developed a hierarchical model that links pinnipeds terrestrial sites sightings-at-sea estimates abundance, spatial distribution, proportion time spent on land (attendance probability). The structure also allows inclusion predictors may explain variation ecological observation processes. We applied Steller sea lions (Eumetopias jubatus) Glacier Bay, Alaska from opportunistic in-water sightings vessel surveys. Bay provided an ideal test application because data available attendance probability based long-term monitoring. found occurrence water was positively related proximity as would be expected species engages central-place foraging. overall abundance were consistent with reports literature programs. describe has benefit utility park managers who wish better understand overlap between visitors, framework present potential across variety study systems taxa.