Spatiotemporal distribution of foraging in a marine predator: behavioural drivers of hotspot formation

2020 ◽  
Vol 635 ◽  
pp. 187-202
Author(s):  
T Brough ◽  
W Rayment ◽  
E Slooten ◽  
S Dawson
Keyword(s):  
Time Of Day ◽  
Spatiotemporal Distribution ◽  
Temporal Effects ◽  
Marine Predator ◽  
Marine Predators ◽  
Additive Mixed Models ◽  
Density Analysis ◽  
The Times ◽  
Passive Acoustic ◽  
Spatial Locations

Many species of marine predators display defined hotspots in their distribution, although the reasons why this happens are not well understood in some species. Understanding whether hotspots are used for certain behaviours provides insights into the importance of these areas for the predators’ ecology and population viability. In this study, we investigated the spatiotemporal distribution of foraging behaviour in Hector’s dolphin Cephalorhynchus hectori, a small, endangered species from New Zealand. Passive acoustic monitoring of foraging ‘buzzes’ was carried out at 4 hotspots and 6 lower-use, ‘reference areas’, chosen randomly based on a previous density analysis of visual sightings. The distribution of buzzes was modelled among spatial locations and on 3 temporal scales (season, time of day, tidal state) with generalised additive mixed models using 82000 h of monitoring data. Foraging rates were significantly influenced by all 3 temporal effects, with substantial variation in the importance and nature of each effect among locations. The complexity of the temporal effects on foraging is likely due to the patchy nature of prey distributions and shows how foraging is highly variable at fine scales. Foraging rates were highest at the hotspots, suggesting that feeding opportunities shape fine-scale distribution in Hector’s dolphin. Foraging can be disrupted by anthropogenic influences. Thus, information from this study can be used to manage threats to this vital behaviour in the locations and at the times where it is most prevalent.

scholarly journals Analysis of Space Usage on Train Station Platforms Based on Trajectory Data

2020 ◽  
Vol 12 (20) ◽  
pp. 8325
Author(s):  
Mira Küpper ◽  
Armin Seyfried
Keyword(s):  
Waiting Times ◽  
Time Of Day ◽  
Level Of Service ◽  
Trajectory Data ◽  
Specific Level ◽  
Train Station ◽  
Flow Profiles ◽  
Realistic Assessment ◽  
The Times ◽  
Measurement And Evaluation

The functionality of railway platforms could be assessed by level of service concepts. They describe interactions between humans and the built environment and allow one to rate risks due to overcrowding. To improve existing concepts, a detailed analysis of how pedestrians use the space was performed, and new measurement and evaluation methods are introduced. Trajectories of passengers at platforms in Bern and Zurich Hardbrücke (Switzerland) were analysed. Boarding and alighting passengers show different behaviour, considering the travel paths, waiting times and mean speed. Density, speed and flow profiles were exploited and a new measure for the occupation of space is introduced. The analysis has shown that it is necessary to filter the data in order to reach a realistic assessment of the level of service. Three main factors should be considered: the time of day, the times when trains arrive and depart and the platform side. Therefore, density, speed and flow profiles were averaged over one minute and calculated depending on the train arrival. The methodology developed in this article is the basis for enhanced and more specific level of service concepts and offers the possibility to optimise planning of transportation infrastructures with regard to functionality and sustainability.

scholarly journals Test of unmanned surface vehicles to conduct remote focal follow studies of a marine predator

2020 ◽  
Vol 635 ◽  
pp. 1-7
Author(s):  
CE Kuhn ◽  
A De Robertis ◽  
J Sterling ◽  
CW Mordy ◽  
C Meinig ◽  
...  
Keyword(s):  
Animal Behavior ◽  
Depth Distribution ◽  
Separation Distance ◽  
Callorhinus Ursinus ◽  
Unmanned Surface Vehicles ◽  
Marine Predator ◽  
Marine Predators ◽  
Fur Seals ◽  
Fur Seal ◽  
Solar Powered

We tested the feasibility of using Saildrone unmanned wind- and solar-powered surface vehicles to conduct remote focal follow studies of northern fur seals Callorhinus ursinus. Using Argos satellite and transmitted GPS locations, the Saildrones followed a fur seal while recording oceanographic conditions and mapping prey abundance and depth distribution using a scientific echosounder. The Saildrones successfully followed 6 fur seals over 2.4 ± 0.2 d (mean ± SE) and 149.7 ± 16.3 km of the foraging path. Median separation distance between the Saildrone and fur seal path was 0.65 ± 0.1 km and average time separation was 9.9 ± 1.4 h, with minimum time separations ranging from 1.9-4.9 h. Time and distance separation were a function of both animal behavior and study design. Our results show that Saildrones can approach satellite tracked marine predators from long distances and follow them over extended periods while collecting oceanographic and prey data. These successful focal follows demonstrate that unmanned surface vehicles are a valuable tool for collecting data on fine-scale relationships between marine predators, their prey, and the environment.

The Nutritional Ecology of Marine Apex Predators

2020 ◽  
Vol 12 (1) ◽  
pp. 361-387 ◽  
Author(s):  
Gabriel E. Machovsky-Capuska ◽  
David Raubenheimer
Keyword(s):  
Ecological Niche ◽  
Energy Content ◽  
Nutritional Ecology ◽  
Ecological Interactions ◽  
Multidimensional Approach ◽  
Apex Predators ◽  
Marine Predator ◽  
Marine Predators ◽  
Nutritional Geometry ◽  
Niche Concept

Apex predators play pivotal roles in marine ecosystems, mediated principally through diet and nutrition. Yet, compared with terrestrial animals, the nutritional ecology of marine predators is poorly understood. One reason is that the field has adhered to an approach that evaluates diet principally in terms of energy gain. Studies in terrestrial systems, by contrast, increasingly adopt a multidimensional approach, the nutritional geometry framework, that distinguishes specific nutrients and calories. We provide evidence that a nutritional approach is likewise relevant to marine apex predators, then demonstrate how nutritional geometry can characterize the nutrient and energy content of marine prey. Next, we show how this framework can be used to reconceptualize ecological interactions via the ecological niche concept, and close with a consideration of its application to problems in marine predator research.

Abstract 143: Evaluation of Interval Times from Onset to Recanalization in Patients Undergoing Endovascular Therapy in the IMS III Trial

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Mayank Goyal ◽  
Bijoy Menon ◽  
Liqiong Fan ◽  
Andrew Demchuk ◽  
Sharon Yeatts ◽  
...  
Keyword(s):  
Endovascular Therapy ◽  
Multiple Comparisons ◽  
Time Of Day ◽  
Endovascular Techniques ◽  
Trial Duration ◽  
Night Time ◽  
Time Intervals ◽  
After Hours ◽  
The Times ◽  
Iv Tpa

Background: There were significant delays in achieving recanalization observed in the IA arm of IMS III. A detailed analysis of the workflow helps to identify factors contributing to overall delay. Methods: In 418 subjects randomized to the IA arm, the following time intervals were calculated: stroke onset to ED arrival; ED to CT; CT to start of IV tPA; IV tPA to randomization; randomization to groin puncture; groin puncture to thrombus identification; thrombus identification to start of IA therapy; start of IA therapy to reperfusion. The effects of time of day and general anesthesia (GA) on workflow were evaluated. The change of ED to reperfusion and groin puncture to reperfusion over the study period were also evaluated. All times are reported as medians (with IQR).Kruskal-Wallis test was applied. Results: Time intervals are shown in figure 1. Intubation had no significant effect on the overall workflow time. The time from CT to groin puncture during business hours (Mon-Fri; 0800-1700) was 119 min (n=201; IQR 49 min) and after hours was 141 min (n=203; IQR 54 min, p <0.0001). The time from CT to groin puncture during day time (0800-2100) was 127 min (n=341; IQR: 51 min) and during night time was 142 min (n=63; IQR 60 min, p=0.0012). After adjusting for multiple comparisons (Bonferroni method), the times from ED to reperfusion (316 min in 1st quartile to 246 min in last quartile,p<0.0001), and groin puncture to reperfusion (145 min in 1st quartile to 120 min in last quartile;p=0.0005) decreased over the trial duration. Conclusion: In the endovascular arm of the IMS III trial there were significant delays from start of IV tPA to groin puncture. Endovascular techniques used in the trial were quite inefficient in achieving recanalization. Use of GA did not result in additional delays. Endovascular treatment outside of daytime hours did result in slight additional delays. These data may help in designing, optimizing and documenting workflow in current and future endovascular trials.

scholarly journals Dusky sharks (Carcharhinus obscurus) undertake large-scale migrations between tropical and temperate ecosystems

2018 ◽  
Vol 75 (9) ◽  
pp. 1525-1533 ◽  
Author(s):  
Matias Braccini ◽  
Simon de Lestang ◽  
Rory McAuley
Keyword(s):  
Large Scale ◽  
Fork Length ◽  
Austral Summer ◽  
Seasonal Migration ◽  
Marine Predator ◽  
Marine Predators ◽  
The North ◽  
Large Scale Network ◽  
Carcharhinus Obscurus ◽  
Scale Network

Understanding the large-scale migrations of marine predators can allow better representation of their population dynamics. The migration biology of dusky sharks (Carcharhinus obscurus), a cosmopolitan large marine predator with very low resilience to fishing, was quantified using a large-scale network of acoustic receivers deployed across Western Australia. Time-series plotting of individual shark detections and modified logistic modelling were used to determine the timing of acoustically tagged sharks’ seasonal migration, the proportion of the population migrating, and the size at which sharks start to migrate. Large (>200 cm fork length) dusky sharks migrated between areas closed (north) and open (south) to commercial shark fishing. There was limited evidence that smaller sharks occurred in the northern study area, whereas several larger individuals of both sexes undertook repeated north–south displacements, moving between disparate ecosystems within the Indian Ocean (21.7°S–35.4°S) and covering round-trip distances of 2000–3000 km per migratory event. For migrating individuals, the probability of occurring in the north was high in the austral winter–spring and low (males) to moderate (females) during the austral summer–autumn.

scholarly journals Ontogenetic partial migration is associated with environmental drivers and influences fisheries interactions in a marine predator

2018 ◽  
Vol 75 (4) ◽  
pp. 1383-1392 ◽  
Author(s):  
James S E Lea ◽  
Bradley M Wetherbee ◽  
Lara L Sousa ◽  
Choy Aming ◽  
Neil Burnie ◽  
...  
Keyword(s):  
Protected Areas ◽  
Spatial Ecology ◽  
Animal Movement ◽  
Partial Migration ◽  
Environmental Drivers ◽  
Conservation Strategies ◽  
Tiger Shark ◽  
Marine Predator ◽  
Additive Mixed Models ◽  
Fisheries Interactions

Abstract The ability to predict animal movement based on environmental change is essential for understanding the dynamic nature of their spatial ecology, and in turn the effectiveness of conservation strategies. We used a large marine predator that displays partial migration (the tiger shark Galeocerdo cuvier) as a model to test the role of oceanic conditions in predicting the space-use of different size classes. By using generalized additive mixed models (GAMMs), we revealed that environmental variables (sea surface temperature, primary productivity, thermal fronts, and bathymetry) had much greater predictive power for the movements of large, migratory tiger sharks than for small, resident individuals. We also found that coverage of tiger shark movements within “shark sanctuaries” (protected areas specifically for sharks) in the northwest Atlantic could be increased from 12 to 52% through inclusion of Bermuda’s waters. However, as large tiger sharks are migratory, over 80% of potential longline fisheries interactions would still occur outside the boundaries of even the expanded protected areas. This emphasises that management of highly migratory species needs to be dynamic and account for changing interactions with fisheries over time, which in a changing climate may rely on predicting movements based on oceanic conditions to be effective.

scholarly journals Applying Behavioral and Physiological Measures to Assess the Relative Impact of the Prolonged COVID-19 Pandemic Closure on Two Mammal Species at the Oregon Zoo: Cheetah (A. jubatus) and Giraffe (G. c. reticulata and G. c. tippelskirchii)

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3526
Author(s):  
Laurel B. Fink ◽  
Candace D. Scarlata ◽  
Becca VanBeek ◽  
Todd E. Bodner ◽  
Nadja C. Wielebnowski
Keyword(s):  
Transition Period ◽  
Time Of Day ◽  
Individual Behavior ◽  
Initial Time ◽  
Hormonal Changes ◽  
Social Changes ◽  
Mammal Species ◽  
Before And After ◽  
Presence And Absence ◽  
The Times

The effect of visitor presence on zoo animals has been explored in numerous studies over the past two decades. However, the opportunities for observations without visitors have been very limited at most institutions. In 2020, the Oregon Zoo was closed, in response to the global SARS-CoV-2 (COVID-19) pandemic, from 15 March 2020 to 12 July 2020, resulting in approximately four consecutive months without visitor presence. This study aimed to quantify potential behavioral and hormonal changes expressed during two transition periods in zoo visitor attendance: the initial time period before and after closure in March 2020 and time before and after reopening in July 2020. Fecal glucocorticoid metabolite (fGM) concentrations of resident giraffes (n = 2) and cheetahs (n = 2) were tracked using enzyme immunoassay (EIA) analyses. Average fGM concentrations during the two transition periods were compared using a two-way mixed ANOVA. Additionally, twice-weekly scan sampling was used to quantify behavioral observations across the transitions, which were analyzed as individual behavior proportions. Individual behavior proportions were compared across the Zoo’s opening status and time of day using Kruskal–Wallis (H) tests. The results of our analyses showed the following outcomes: (1) significant increases in fGM concentrations for cheetahs and giraffes between the transition periods but not within them; (2) a significant increase in time spent ‘not visible’ in the cheetahs in the second transition period; and (3) increased vigilance behaviors in the giraffes immediately after the Zoo’s closure. However, the changes observed in fGM concentrations may be more strongly correlated with concomitant social changes (giraffes) and some medical events (cheetahs) rather than with the Zoo’s opening status. Nevertheless, this study was able to quantify differences in behavioral frequencies and fGM concentration in cheetahs and giraffes at the Oregon Zoo during the times of transition between visitor’s presence and absence. The results indicate that, while there was a possible, but relatively minor impact of the presence and absence of visitors on some behaviors, the differences observed in fGM concentration may have been more affected by some of the concomitant social changes and medical events that happened during the same period than by the presence or absence of visitors.

scholarly journals Spectral dependency of the human pupillary light reflex. Influences of pre-adaptation and chronotype.

2021 ◽  
Author(s):  
Johannes Zauner ◽  
Herbert Plischke ◽  
Hans Strasburger
Keyword(s):  
Color Vision ◽  
Stimulus Duration ◽  
Light Stimulus ◽  
Monochromatic Light ◽  
Time Of Day ◽  
Controlled Study ◽  
Pupillary Constriction ◽  
Additive Mixed Models ◽  
Light Stimuli ◽  
The Individual

Non-visual photoreceptors (ipRGCs) and rods both exert a strong influence on the human pupil, yet pupil models regularly use cone-derived sensitivity as their basis. This inconsistency is further exacerbated by the fact that circadian effects can modulate the wavelength sensitivity. We assessed the pupillary reaction to monochromatic light stimuli in the mesopic range. Pupil size for eighty-three healthy participants with normal color vision was measured in nine experimental protocols with varying series of continuous or discontinuous light stimuli under Ganzfeld conditions, presented after 90 seconds of dark adaptation. One hundred and fifty series of stimulation were conducted across three experiments, and were analyzed for wavelength-dependency on the pupillary constriction amplitude (PCA), conditional on experimental settings and individual traits. Traits were surveyed by questionnaire; color vision was tested by  Ishihara plates  or the  Lanthony D15  test. Data were analyzed with generalized additive mixed models (GAMM). The pupillary constriction amplitude response is consistent with L+M-cone derived sensitivity when the series of light stimuli is continuous, i.e., is not interrupted by periods of darkness, but not otherwise. The results also show that a mesopic illuminance weighing led to an overall best prediction of pupillary constriction compared to other types of illuminance measures. IpRGC influence on PCA is not readily apparent from the results. When we explored the interaction of chronotype and time of day on the wavelength dependency, differences consistent with ipRGC influence became apparent. The models indicate that subjects of differing chronotype show a heightened or lowered sensitivity to short wavelengths, depending on their time of preference. IpRGC influence is also seen in the post-illumination pupil reflex if the prior light-stimulus duration is one second. However, shorter wavelengths than expected become more important if the light-stimulus duration is fifteen or thirty seconds. The influence of sex on PCA was present, but showed no interaction with wavelength. Our results help to define the conditions, under which the different wavelength sensitivities in literature hold up for monochromatic light settings. The chronotype effect might signify a mechanism for strengthening the individual´s chronotype, but demands replication in a controlled study.

A Temporal Phase Mutation of Chlorophyll Fluorescence in Triazine-Resistant Brassica napus

1987 ◽  
Vol 42 (6) ◽  
pp. 775-778
Author(s):  
Jack Dekker ◽  
Barbara Westfall
Keyword(s):  
Chlorophyll Fluorescence ◽  
Brassica Napus ◽  
Field Experiments ◽  
Leaf Disc ◽  
Time Of Day ◽  
Temporal Organization ◽  
Intensity Measurements ◽  
Differential Pattern ◽  
Phase Mutation ◽  
The Times

The objectives of this study were to determine if there were variations in triazine-resistant and -susceptible Brassica napus leaf disc chlorophyll fluorescence (LCF) intensity in terms of: age of leaf on the plant and time of day. In growth room and field experiments triazine-susceptible B. napus cv. “Tower”, and triazine-resistant B. napus cv. OAC Triton” were used. Chlorophyll fluorescence intensity measurements were made 30 min after disc removal. In both environments, two periods of reduced photosynthetic efficiency occurred in the diurnal. The times that these periods occurred during the diurnal differed between biotvpes. A phase shift in LCF maxima between resistant and susceptible biotypes resulted in two periods, early and late in the light period of the diurnal, of increased LCF in resistant tissue. This differential pattern in LCF is support for the hypothesis that triazine resistance chloroplast alterations could imply an alteration in the temporal organization of chloroplast physiological function.

Broilers’ behavioural adjustments when submitted to natural heat stress and fed different maize particle sizes in the diet

2019 ◽  
Vol 157 (9-10) ◽  
pp. 743-748 ◽  
Author(s):  
M. M. Santos ◽  
J. B. F. Souza-Junior ◽  
J. P. A. F. Queiroz ◽  
M. K. O. Costa ◽  
H. F. F. Lima ◽  
...  
Keyword(s):  
Heat Stress ◽  
Feed Intake ◽  
Thermal Environment ◽  
Geometric Mean ◽  
Thermal Conditions ◽  
Time Of Day ◽  
Particle Sizes ◽  
Behavioural Adjustment ◽  
The Times ◽  
Body Heat

AbstractSince behavioural adjustments are an important line of defence against thermal stress, either due to their energy efficiency or to efficiency at preventing overheating, we aimed to evaluate whether broilers fed different maize particle sizes adjusted their behaviour to deal with heat stress challenges. At several times a day, the behaviour of 220 naked neck broilers was evaluated. These broilers were fed with isonutritive diets containing maize with different geometric mean diameters (GMD): 605 and 2280 μm. The thermal environment was monitored during the experiment. Panting and open wings were the only behaviours that showed differences between the times of day (P < 0.05). However, GMD showed a significant effect on feed intake and panting (P < 0.05). The interaction between GMD and time of day was significant only on panting (P < 0.05). Although no daily variation was observed, the highest feed intake was observed in broilers fed the diet containing maize with a GMD of 2280 μm. Less than 5% of the broilers were observed drinking water during the day. Open wings was the behavioural adjustment most used by broilers from 10:00 h, and remained elevated until 14:00 h for both GMDs. The birds panted more when fed the diet containing maize with a GMD of 2280 μm. In conclusion, broilers adjust their behaviour to dissipate excess body heat from the environment and as a result of feed intake. Coarse particles of maize in the diet increase the thermal challenge of broilers since the environment also provides stressful thermal conditions.

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