scholarly journals Multi-state mark-recapture models as a novel approach to estimate factors affecting attendance patterns of lactating subantarctic fur seals from Marion Island

2014 ◽  
Vol 27 (3) ◽  
pp. 252-262 ◽  
Author(s):  
M. Wege ◽  
M. Nevoux ◽  
P.J.N. de Bruyn ◽  
M.N. Bester
Keyword(s):  
Capture Probability ◽  
Marion Island ◽  
Mark Recapture ◽  
Factors Affecting ◽  
Attendance Patterns ◽  
Fur Seals ◽  
Novel Approach ◽  
Winter Foraging ◽  
Ecological Parameters ◽  
Subantarctic Fur Seals

AbstractObserver-based studies often underestimate key ecological parameters. Here a fresh approach was used to analyse six years (2006–11) of attendance cycles to estimate foraging trip lengths of a lactating flipper-tagged otariid: subantarctic fur seals at Marion Island. Multi-state mark-recapture models were used to calculate detection failures of females, correct estimates accordingly, and investigate the effects of year, season, pup sex and the presence of a telemetry device on attendance cycle parameters. There were no differences between corrected and uncorrected attendance data. This is attributed to the high capture probability across all seasons (range: 83–98%). This illustrates that observer-based studies are useful to augment telemetry studies. Only season and pup sex had a significant impact on female provisioning rates. In winter, foraging trip durations were longer (t-value=25.22,P<0.0001) and attendance durations shorter (t-value=-2.15,P=0.01) than during summer. Females with female pups spent a higher proportion of their time on land (χ2=6.6,P<0.05). Male pups have higher growth demands and are larger which suggests they can deplete female milk-stores faster.

Pup growth and maternal attendance patterns in Subantarctic fur seals

2002 ◽  
Vol 37 (1) ◽  
pp. 13-19 ◽  
Author(s):  
S.P Kirkman ◽  
M.N. Bester ◽  
G.J.G. Hofmeyr ◽  
P.A. Pistorius ◽  
A.B. Makhado
Keyword(s):  
Attendance Patterns ◽  
Fur Seals ◽  
Pup Growth ◽  
Subantarctic Fur Seals

Attendance behaviour of Antarctic and subantarctic fur seal females at Marion Island

1990 ◽  
Vol 2 (4) ◽  
pp. 309-312 ◽  
Author(s):  
Marthán N. Bester ◽  
Peter A. Bartlett
Keyword(s):  
Arctocephalus Gazella ◽  
Marion Island ◽  
Fur Seals ◽  
Fur Seal ◽  
Lactating Females ◽  
The Mean ◽  
Temperate Environment ◽  
The Difference ◽  
Antarctic Fur Seals ◽  
Subantarctic Fur Seals

The female attendance behaviour of Antarctic fur seals (Arctocephalus gazella) and subantarctic fur seals (A.tropicalis), which breed sympatrically on subantarctic Marion Island, was investigated. Over the same period after the breeding season, the mean duration of feeding trips to sea, and percentage of time spent at sea, did not differ significantly between lactating females of the two species. The difference in mean duration of shore visits was significant and the longer onshore attendance of A. tropicalis probably related to the lower demand by their pups which grow at a slower rate. The subpolar maternal adaptations of A. gazella were unchanged under the more temperate environment at Marion Island, and it remains to be established unequivocally whether conditions there are limiting to the species.

scholarly journals Overlap and temporal variation in the diets of sympatric Antarctic and Subantarctic fur seals (Arctocephalus spp.) at Marion Island, Prince Edward Islands

2018 ◽  
Vol 37 (1) ◽  
pp. 1451142 ◽  
Author(s):  
Ryan R. Reisinger ◽  
Marietjie Landman ◽  
Nonkoliso Mgibantaka ◽  
Malcolm J. Smale ◽  
Marthán N. Bester ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Marion Island ◽  
Prince Edward Islands ◽  
Fur Seals ◽  
Subantarctic Fur Seals

Vagrant Subantarctic fur seals at Bouvetøya

2006 ◽  
Vol 41 (1) ◽  
pp. 145-146 ◽  
Author(s):  
G. J. G. Hofmeyr ◽  
M. N. Bester ◽  
S. P. Kirkman
Keyword(s):  
Fur Seals ◽  
Subantarctic Fur Seals

Age structure, growth, and demographic parameters in breeding-age female subantarctic fur seals, Arctocephalus tropicalis

2004 ◽  
Vol 82 (7) ◽  
pp. 1043-1050 ◽  
Author(s):  
Willy Dabin ◽  
Gwénaël Beauplet ◽  
Enrique A Crespo ◽  
Christophe Guinet
Keyword(s):  
Age Distribution ◽  
Reproductive Rate ◽  
Reproductive Period ◽  
Demographic Parameters ◽  
Island Population ◽  
Female Population ◽  
Regulatory Processes ◽  
Fur Seals ◽  
Subantarctic Fur Seals ◽  
Arctocephalus Tropicalis

Age distribution was estimated for 108 breeding-age female subantarctic fur seals, Arctocephalus tropicalis (Gray, 1872), sampled during the 1999–2000 breeding season on Amsterdam Island, southern Indian Ocean. The growth features were described and demographic parameters assessed from transversal life tables constructed for this female population. The breeding females had a longer mean body length than was observed for other breeding populations of the same species. These females also showed a later start to reproduction (6 years old), a lower overall age-specific reproductive rate (R6–16 = 48.0%), and a lower survival in older age classes (>13 years). Females reproduced up to a maximum age of 16 years, with none older than 19 years observed in the colony, suggesting an apparent senescence in the population. This consequently reduced the theoretical reproductive period of the females, which has led to a lower number of reproductive outputs per individual (i.e., 3.65 weaned pups per female throughout its reproductive life). Although such differences between islands may be related to genotypic traits, these results are consistent with low food availability and suggest that density-dependent regulatory processes operate on the Amsterdam Island population.

Factors Affecting Mobile Advertising

2010 ◽  
pp. 58-76 ◽  
Author(s):  
Ramin Vatanparast
Keyword(s):  
Conceptual Model ◽  
Influencing Factors ◽  
Direct Marketing ◽  
Point Of View ◽  
Mobile Advertising ◽  
Comprehensive Understanding ◽  
Holistic View ◽  
Factors Affecting ◽  
Targeted Advertising ◽  
Novel Approach

Mobile advertising holds strong promises to become the most highly targeted advertising medium offering new ways to target messages to users. By utilizing mobile advertising, companies can run marketing campaigns targeted to tens of thousands of people with a fraction of the costs and time in comparison to other direct marketing mediums. However, as mobile advertising is a novel approach, many aspects of it still need further investigation. Little is known regarding the effectiveness of mobile advertising campaigns and the factors contributing to their success. This chapter aims to provide a comprehensive understanding of the advertising space and its influencing factors. First, the study investigates factors that influence mobile advertising from both the industry’s and consumer’s point of view. Second, based on a review of previous studies in the field, the author proposes a conceptual model for mobile advertising, which categorizes the factors in different groups and provides a holistic view of their impact in the mobile advertising space.

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