نتایج جستجو برای: seals
تعداد نتایج: 4450 فیلتر نتایج به سال:
The purpose of this paper is ro summarise and discuss the changes in glaciers, king penguins and fur seals reported by the nine wintering parties and 11 summer expeditions that have visited Heard Island since 1947, with emphasis upon those of the years between 1947 and 1971. These early years were notable for an initial period (1947-55) of minimal change, and a subsequent period (1963-71) of ra...
Prehistoric exploitation of marine mammals in the northeastern Pacific has been a subject of considerable attention since 1992 when Hildebrandt and Jones used an optimal foraging model to argue that when congregated in rookeries, seals and sea lions represent highly attractive resources vulnerable to overpredation. Using archaeofaunal data from sites along the Oregon and California coasts they ...
The movement and dietary history of individuals can be studied using stable isotope records in archival keratinous tissues. Here, we present a chronology of temporally fine-scale data on the trophic niche of otariid seals by measuring the isotopic signature of serially sampled whiskers. Whiskers of male Antarctic fur seals breeding at the Crozet Islands showed synchronous and regular oscillatio...
The polymerase chain reaction (PCR) was used to determine the tissue distribution of phocine herpesvirus-1 (PhHV-1) DNA in 20 stranded Pacific harbour seals (17 pups and three seals older than one year) that died during rehabilitation. The aim was to begin to define stages of infection and to investigate the relation between the presence of PhHV-1 in tissues, histological lesions and serology. ...
Widely ranging marine predators often adopt stereotyped, energy-saving behaviours to minimize the energetic cost of transport while maximizing energy gain. Environmental and anthropogenic disturbances can disrupt energy balance by prompting avoidance behaviours that increase transport costs, thereby decreasing foraging efficiency. We examined the ability of 12 free-ranging, juvenile northern el...
Seals and humans often target the same food resource, leading to competition. This is of mounting concern with fish stocks in global decline. Grey seals were tracked from southeast Ireland, an area of mixed demersal and pelagic fisheries, and overlap with fisheries on the Celtic Shelf and Irish Sea was assessed. Overall, there was low overlap between the tagged seals and fisheries. However, whe...
Elephant seals naturally experience prolonged periods of absolute food and water deprivation (fasting). In humans, rats and mice, prolonged food deprivation activates the renin-angiotensin system (RAS) and increases oxidative damage. In elephant seals, prolonged fasting activates RAS without increasing oxidative damage likely due to an increase in antioxidant defenses. The mechanism leading to ...
Sealing is a crucial factor in most aspects of our daily lives within our homes and vehicles. Among the hundreds of seals in the average vehicle, modern turbocharged engines include at least one seal that is required to carry out a similar duty to those of interest in this paper; that is, separating the engine air flow from bearing oil. Also in the oil and gas industry, or in a petrochemical pr...
Fur seals (pinnipeds of the family Otariidae) display two fundamentally different patterns of sleep: bilaterally symmetrical slow-wave sleep (BSWS) as seen in terrestrial mammals and slow-wave sleep (SWS) with a striking interhemispheric EEG asymmetry (asymmetrical SWS or ASWS) as observed in cetaceans. We examined the effect of preventing fur seals from sleeping in BSWS on their pattern of sle...
The compound effects of changing habitats, ecosystem interactions, and fishing practices have implications for the management of Antarctic krill and conservation of its predators. For Antarctic pack-ice seals, an important group of krill predators, we estimate the density and krill consumption in theWest Antarctic Peninsula (WAP)–WesternWeddell Sea area, the main fishery region; and we consider...
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