Data were collected from 227 ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus) killed by polar bears (Ursus maritimus) in the western arctic and the eastern high arctic. During periods of high ringed seal productivity, pups constituted at least half of the seals killed in both areas during the spring. Bearded seals were taken less often than ringed seals in both areas but were more important as prey to polar bears in the western arctic. Carcass utilization was significantly higher in the eastern high arctic than in the western arctic although the reason was not apparent. Scavenging of unutilized seal remains is probably of great importance to the survival of large numbers of arctic foxes (Alopex lagopus) through the winter. Key words: Ursus maritimus, Phoca hispida, Erignathus barbatus, predation, interspecific relationships, Arctic Ocean mammals

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Mites from the family Halarachnidae Oudemans 1906 are obligate endoparasites that colonize the respiratory tracts of free-living and captive marine mammals. Infestations can range from mild to severe and result in respiratory tract irritation or impairment. Nasopulmonary acariasis was determined to be a contributing cause of death among several southern sea otters Enhydra lutris nereis Merriam 1904 in a longitudinal study of otter mortality, and proximity to Pacific harbor seals Phoca vitulina richardii Gray 1864 was a significant risk factor for sea otter infestation. Beyond scattered opportunistic reports, each halarachnid mite species' affinity for particular hosts and the extent of mite transmission between host species is poorly understood. We investigated the identity and prevalence of nasopulmonary mites from Pacific harbor seals, California sea lions Zalophus californianus Lesson 1828, northern elephant seals Mirounga angustirostris Gill 1866, northern fur seals Callorhinus ursinus Linnaeus 1758, and Guadalupe fur seals Arctocephalus philippii townsendi Merriam 1897 to complement published nasopulmonary mite findings from sympatric southern sea otters during a comparable timeframe. Halarachnid mite infestation was common among California sea lions (74.1%), northern fur seals (73.3%), and northern elephant seals (46.6%), but was less common among harbor seals (18.7%) and Guadalupe fur seals (8.8%). Observed host-mite relationships suggest a distinct host specificity, with genus Orthohalarachne infesting otariids, and genus Halarachne infesting phocids and lutrinids along the California coast. Harbor seals and southern sea otters were the primary hosts of H. halichoeri , but one nothern elephant seal was infested with both H. miroungae and a single H. halichoeri. We also present the first high-resolution SEM images for H. miroungae and O. attenuata and possible evidence for a new host record for H. halichoeri .

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