scholarly journals The influence of preceding dive cycles on the foraging decisions of Antarctic fur seals

2015 ◽  
Vol 11 (7) ◽  
pp. 20150227 ◽  
Author(s):  
T. Iwata ◽  
K. Q. Sakamoto ◽  
E. W. J. Edwards ◽  
I. J. Staniland ◽  
P. N. Trathan ◽  
...  
Keyword(s):  
Empirical Studies ◽  
Three Dimensional ◽  
Mouth Opening ◽  
Foraging Strategy ◽  
Horizontal Distance ◽  
Fur Seals ◽  
Linear Distance ◽  
Foraging Experience ◽  
Past Experiences ◽  
Antarctic Fur Seals

The foraging strategy of many animals is thought to be determined by their past experiences. However, few empirical studies have investigated whether this is true in diving animals. We recorded three-dimensional movements and mouth-opening events from three Antarctic fur seals during their foraging trips to examine how they adapt their behaviour based on past experience—continuing to search for prey in the same area or moving to search in a different place. Each dive cycle was divided into a transit phase and a feeding phase. The linear horizontal distance travelled after feeding phases in each dive was affected by the mouth-opening rate during the previous 244 s, which typically covered two to three dive cycles. The linear distance travelled tended to be shorter when the mouth-opening rate in the previous 244 s was higher, i.e. seals tended to stay in the same areas with high prey-encounter rates. These results indicate that Antarctic fur seals follow decision-making strategies based on the past foraging experience over time periods longer than the immediately preceding dive.

Diving behaviour of lactating Antarctic fur seals

1992 ◽  
Vol 70 (5) ◽  
pp. 919-928 ◽  
Author(s):  
I. L. Boyd ◽  
J. P. Croxall
Keyword(s):  
Mixed Layer ◽  
Foraging Strategy ◽  
Dive Depth ◽  
Diving Behaviour ◽  
Cumulative Probability ◽  
Surface Mixed Layer ◽  
Sea Temperature ◽  
Fur Seals ◽  
Fur Seal ◽  
Antarctic Fur Seals

The diving behaviour of 11 lactating female Antarctic fur seals (Arctocephalus gazella) was recorded for a total of 254 animal-days at sea. Median and maximum dive depths for individuals varied from 8 to 19 m and from 82 to 181 m, respectively, and median and maximum dive durations from 0.75 to 1.17 min and from 2.8–10.0 min, respectively. Theoretical aerobic diving limits were exceeded on < 1% of dives. Dives were mainly V-shaped. Sixty percent of dives were to less than 20 m depth, and these dives were distinguished from deep dives (> 20 m) by having slower rates of descent and ascent and by being confined to the mixed layer at the ocean surface, as judged by records of sea temperature obtained concurrently with records of depth. Dives were grouped into bouts, defined by inflexion points observed in the cumulative probability distribution of surface interval after probit transformation. Bouts (defined by preceding and succeeding surface intervals lasting 13–24 min) occurred within a diel pattern of diving activity, with 74–85% of dives occurring at night. The pattern of diving, in terms of division into bouts, showed greater differences between individual seals than did dive depth and duration. Dives tended to be shorter and shallower later in lactation. Most variation in diving behaviour between individuals was in terms of the proportion of available time spent foraging, bout frequency, and bout duration. The foraging strategy in the Antarctic fur seal is geared to exploiting prey within the surface mixed layer.

scholarly journals Three Dimensional Approaches to Personality Disorders: a Review on Personality Functioning, Personality Structure, and Personality Organization

2021 ◽  
Vol 23 (7) ◽  
Author(s):  
Susanne Hörz-Sagstetter ◽  
Ludwig Ohse ◽  
Leonie Kampe
Keyword(s):  
Personality Disorders ◽  
Empirical Studies ◽  
Three Dimensional ◽  
Personality Pathology ◽  
Personality Structure ◽  
Assessment Instruments ◽  
Personality Organization ◽  
Personality Functioning ◽  
Clinical Observations ◽  
Categorical Classification

Abstract Purpose of Review The concept of personality functioning (Alternative DSM-5 Model of Personality Disorders) has led to increased interest in dimensional personality disorder diagnosis. While differing markedly from the current categorical classification, it is closely related to the psychodynamic concepts of personality structure and personality organization. In this review, the three dimensional approaches, their underlying models, and common instruments are introduced, and empirical studies on similarities and differences between the concepts and the categorical classification are summarized. Additionally, a case example illustrates the clinical application. Recent Findings Numerous studies demonstrate the broad empirical basis, validated assessment instruments and clinical usefulness of the dimensional concepts. Their advantages compared to the categorical approach, but also the respective differences, have been demonstrated empirically, in line with clinical observations. Summary Evidence supports the three dimensional concepts, which share conceptual overlap, but also entail unique aspects of personality pathology, respectively.

scholarly journals A developmentally descriptive method for quantifying shape in gastropod shells

2020 ◽  
Vol 17 (163) ◽  
pp. 20190721
Author(s):  
J. Larsson ◽  
A. M. Westram ◽  
S. Bengmark ◽  
T. Lundh ◽  
R. K. Butlin
Keyword(s):  
Empirical Studies ◽  
Three Dimensional ◽  
Shell Shape ◽  
Large Set ◽  
Littorina Saxatilis ◽  
Shape Variation ◽  
Gastropod Shell ◽  
Geometric Morphometric ◽  
Wide Range ◽  
Descriptive Method

The growth of snail shells can be described by simple mathematical rules. Variation in a few parameters can explain much of the diversity of shell shapes seen in nature. However, empirical studies of gastropod shell shape variation typically use geometric morphometric approaches, which do not capture this growth pattern. We have developed a way to infer a set of developmentally descriptive shape parameters based on three-dimensional logarithmic helicospiral growth and using landmarks from two-dimensional shell images as input. We demonstrate the utility of this approach, and compare it to the geometric morphometric approach, using a large set of Littorina saxatilis shells in which locally adapted populations differ in shape. Our method can be modified easily to make it applicable to a wide range of shell forms, which would allow for investigations of the similarities and differences between and within many different species of gastropods.

scholarly journals Adjustment of an Integrated Geodetic Network Composed of GNSS Vectors and Classical Terrestrial Linear Pseudo-Observations

2021 ◽  
Vol 11 (10) ◽  
pp. 4352
Author(s):  
Tadeusz Gargula
Keyword(s):  
Three Dimensional ◽  
Geodetic Network ◽  
Global Navigation Satellite Systems ◽  
Adjustment Process ◽  
Dimensional System ◽  
Integrated Network ◽  
Satellite Systems ◽  
Linear Distance ◽  
Easy Integration ◽  
Global Navigation Satellite

The paper proposes a new method for adjusting classical terrestrial observations (total station) together with satellite (GNSS-Global Navigation Satellite Systems) vectors. All the observations are adjusted in a single common three-dimensional system of reference. The proposed method does not require the observations to be projected onto an ellipsoid or converted between reference systems. The adjustment process follows the transformation of a classical geodetic network (distances and horizontal and vertical angles) into a spatial linear (distance) network. This step facilitates easy integration with GNSS vectors when results are numerically processed. The paper offers detailed formulas for calculating pseudo-observations (spatial distances) from input terrestrial observations (horizontal and vertical angles, horizontal distances, height of instrument and height of target). The next stage was to set observation equations and transform them into a linear form (functional adjustment model of geodetic observations). A method was provided as well for determining the mean errors of the pseudo-observations, necessary to assess the accuracy of the values following the adjustment (point coordinates). The proposed algorithm was verified in practice whereby an integrated network made up of a GNSS vector network and a classical linear-angular network was adjusted.

Fur seals, whales and tourists: a commercial history of Deception Island, Antarctica

Polar Record ◽  
2009 ◽  
Vol 46 (3) ◽  
pp. 210-221 ◽  
Author(s):  
J. Stephen Dibbern
Keyword(s):  
South Shetland Islands ◽  
Deception Island ◽  
Commercial Activity ◽  
Early 19Th Century ◽  
Cruise Industry ◽  
Shetland Islands ◽  
Fur Seals ◽  
History Of ◽  
The Antarctic ◽  
Antarctic Fur Seals

ABSTRACTDeception Island in the South Shetland Islands was the site of some of the earliest commercial activity to be carried out in the Antarctic with the early 19th century hunting of Antarctic fur seals. Nearly a century later it was the site of the most extensive anchorage for the reconstructed ships and ocean liners used as non-pelagic whale processing factories. Deception was also the site of what is the only successful land based commercial activity in Antarctic history. The Hektor whaling station operated in Whalers Bay from 1912 until 1931. Most of the remains of the station have now been obliterated by the volcanic activity that occurred in the late 1960s and 1970. By the later part of the twentieth century Deception Island had become a regular stop for the growing Antarctic tourist cruise industry. No other place in Antarctica has been so thoroughly identified with commercial activity.

scholarly journals Diving deep into trouble: the role of foraging strategy and morphology in adapting to a changing environment

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Monique Ladds ◽  
David Rosen ◽  
Carling Gerlinsky ◽  
David Slip ◽  
Robert Harcourt
Keyword(s):  
Foraging Strategy ◽  
Central Place ◽  
Dive Duration ◽  
Foraging Strategies ◽  
Body Morphology ◽  
Sea Lions ◽  
Fur Seals ◽  
Adequate Food ◽  
Physiological Capacity ◽  
Total Body Oxygen

Abstract Physiology places constraints on an animal’s ability to forage and those unable to adapt to changing conditions may face increased challenges to reproduce and survive. As the global marine environment continues to change, small, air-breathing, endothermic marine predators such as otariids (fur seals and sea lions) and particularly females, who are constrained by central place foraging during breeding, may experience increased difficulties in successfully obtaining adequate food resources. We explored whether physiological limits of female otariids may be innately related to body morphology (fur seals vs sea lions) and/or dictate foraging strategies (epipelagic vs mesopelagic or benthic). We conducted a systematic review of the increased body of literature since the original reviews of Costa et al. (When does physiology limit the foraging behaviour of freely diving mammals? Int Congr Ser 2004;1275:359–366) and Arnould and Costa (Sea lions in drag, fur seals incognito: insights from the otariid deviants. In Sea Lions of the World Fairbanks. Alaska Sea Grant College Program, Alaska, USA, pp. 309–324, 2006) on behavioural (dive duration and depth) and physiological (total body oxygen stores and diving metabolic rates) parameters. We estimated calculated aerobic dive limit (cADL—estimated duration of aerobic dives) for species and used simulations to predict the proportion of dives that exceeded the cADL. We tested whether body morphology or foraging strategy was the primary predictor of these behavioural and physiological characteristics. We found that the foraging strategy compared to morphology was a better predictor of most parameters, including whether a species was more likely to exceed their cADL during a dive and the ratio of dive time to cADL. This suggests that benthic and mesopelagic divers are more likely to be foraging at their physiological capacity. For species operating near their physiological capacity (regularly exceeding their cADL), the ability to switch strategies is limited as the cost of foraging deeper and longer is disproportionally high, unless it is accompanied by physiological adaptations. It is proposed that some otariids may not have the ability to switch foraging strategies and so be unable adapt to a changing oceanic ecosystem.

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