Comparison of trip duration, activity pattern and diving behaviour by Red-tailed Tropicbirds (Phaethon rubricauda) during incubation and chick-rearing

2010 ◽  
Vol 110 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Julia Sommerfeld ◽  
Janos C. Hennicke
1998 ◽  
Vol 76 (6) ◽  
pp. 1044-1053 ◽  
Author(s):  
Paul M Thompson ◽  
Ann Mackay ◽  
Dominic J Tollit ◽  
Simon Enderby ◽  
Philip S Hammond

Most pinnipeds disperse from centralised terrestrial sites to forage at sea, but the factors that result in variation inforaging-trip characteristics remain unclear. We investigated the influence of sex and body size on the summer foraging activityof radio-tagged harbour seals (Phoca vitulina) from Scotland. Mean foraging-trip duration (range 17–257 h) was stronglycorrelated with mean foraging range (range 4.3–55.0 km), but both were significantly shorter for females. The proportion oftime spent at sea, mean trip duration, and mean foraging range were all positively related to body size. Comparison with datafrom other study areas suggests that both environmental and endogenous factors shape foraging characteristics in this species.These sex and body size related differences in activity pattern and foraging range have important implications for themethodologies currently used to assess the population size, population energy requirements, and diet composition of coastalpinnipeds.


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Elizabeth A McHuron ◽  
Jeremy T Sterling ◽  
Daniel P Costa ◽  
Michael E Goebel

Abstract Quantifying metabolic rates and the factors that influence them is key to wildlife conservation efforts because anthropogenic activities and habitat alteration can disrupt energy balance, which is critical for reproduction and survival. We investigated the effect of diving behaviour, diet and season on field metabolic rates (FMR) and foraging success of lactating northern fur seals (Callorhinus ursinus) from the Pribilof Islands during a period of population decline. Variation in at-sea FMR was in part explained by season and trip duration, with values that ranged from 5.18 to 9.68 W kg−1 (n = 48). Fur seals experienced a 7.2% increase in at-sea FMR from summer to fall and a 1.9% decrease in at-sea FMR for each additional day spent at sea. There was no effect of foraging effort, dive depth or diet on at-sea FMR. Mass gains increased with trip duration and were greater in the fall compared with summer, but were unrelated to at-sea FMR, diving behaviour and diet. Seasonal increases in at-sea FMR may have been due to costs associated with the annual molt but did not appear to adversely impact the ability of females to gain mass on foraging trips. The overall high metabolic rates in conjunction with the lack of any diet-related effects on at-sea FMR suggests that northern fur seals may have reached a metabolic ceiling early in the population decline. This provides indirect evidence that food limitation may be contributing to the low pup growth rates observed in the Pribilof Islands, as a high metabolic overhead likely results in less available energy for lactation. The limited ability of female fur seals to cope with changes in prey availability through physiological mechanisms is particularly concerning given the recent and unprecedented environmental changes in the Bering Sea that are predicted to have ecosystem-level impacts.


2009 ◽  
Author(s):  
Betty A. Schreiber ◽  
R. W. Schreiber
Keyword(s):  

1987 ◽  
Vol 14 (2) ◽  
pp. 143-149 ◽  
Author(s):  
L. René Durán ◽  
Juan Carlos Castilla ◽  
Doris Oliva

The rocky shore of central Chile is heavily harvested by mariscadores de orilla and skin-divers, but their catches are not considered in the fishery statistics. The aim of the present paper is to estimate the intensity of human predation and annual catch of each of the species taken at Las Cruces, Central Chile. The activity pattern of both categories of collectors demonstrate a temporal grouping. The observation of mariscadores de orilla and skin-divers in 3 sectors of fringe totalling 1,500 m of rocky shore during 12 months allowed us to estimate the annual catch per species caught (kg per year).


2021 ◽  
Vol 11 (4) ◽  
pp. 1492-1500
Author(s):  
Yoori Cho ◽  
Sujong Jeong ◽  
Dowon Lee ◽  
Sang‐Woo Kim ◽  
Rokjin J. Park ◽  
...  
Keyword(s):  

Author(s):  
Sascha von Behren ◽  
Tim Hilgert ◽  
Sophia Kirchner ◽  
Bastian Chlond ◽  
Peter Vortisch

Author(s):  
Junli Liu ◽  
Panli Cai ◽  
Jin Dong ◽  
Junshun Wang ◽  
Runkui Li ◽  
...  

The spatiotemporal locations of large populations are difficult to clearly characterize using traditional exposure assessment, mainly due to their complicated daily intraurban activities. This study aimed to extract hourly locations for the total population of Beijing based on cell phone data and assess their dynamic exposure to ambient PM2.5. The locations of residents were located by the cellular base stations that were keeping in contact with their cell phones. The diurnal activity pattern of the total population was investigated through the dynamic spatial distribution of all of the cell phones. The outdoor PM2.5 concentration was predicted in detail using a land use regression (LUR) model. The hourly PM2.5 map was overlapped with the hourly distribution of people for dynamic PM2.5 exposure estimation. For the mobile-derived total population, the mean level of PM2.5 exposure was 89.5 μg/m3 during the period from 2013 to 2015, which was higher than that reported for the census population (87.9 μg/m3). The hourly activity pattern showed that more than 10% of the total population commuted into the center of Beijing (e.g., the 5th ring road) during the daytime. On average, the PM2.5 concentration at workplaces was generally higher than in residential areas. The dynamic PM2.5 exposure pattern also varied with seasons. This study exhibited the strengths of mobile location in deriving the daily spatiotemporal activity patterns of the population in a megacity. This technology would refine future exposure assessment, including either small group cohort studies or city-level large population assessments.


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