Lightscapes of fear: How mesopredators balance starvation and predation in the open ocean

Like landscapes of fear, animals are hypothesized to strategically use lightscapes based on intrinsic motivations. However, longitudinal evidence of state-dependent risk aversion has been difficult to obtain in wild animals. Using high-resolution biologgers, we continuously measured body condition, time partitioning, three-dimensional movement, and risk exposure of 71 elephant seals throughout their 7-month foraging migrations (N = 16,000 seal days). As body condition improved from 21 to 32% fat and daylength declined from 16 to 10 hours, seals rested progressively earlier with respect to sunrise, sacrificing valuable nocturnal foraging hours to rest in the safety of darkness. Seals in superior body condition prioritized safety over energy conservation by resting >100 meters deeper where it was 300× darker. Together, these results provide empirical evidence that marine mammals actively use the three-dimensional lightscape to optimize risk-reward trade-offs based on ecological and physiological factors.

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Spatial variation in female southern elephant seal mass change assessed by an accurate non-invasive photogrammetry method

Antarctic Science ◽

10.1017/s0954102013000059 ◽

2013 ◽

Vol 25 (6) ◽

pp. 731-740 ◽

Cited By ~ 13

Author(s):

Martin Postma ◽

Marthán N. Bester ◽

P.J. Nico De Bruyn

Keyword(s):

Life Cycle ◽

Mass Loss ◽

Marine Mammals ◽

Three Dimensional ◽

Elephant Seal ◽

Southern Elephant Seal ◽

Marion Island ◽

Elephant Seals ◽

Marine Predator ◽

Three Dimensional Models

AbstractPhysically weighing large marine mammals sequentially over time has presented researchers with a logistical challenge and has severely limited sample sizes. Using a well-established photogrammetry method we developed a simple mathematical method to calculate accurate mass measurements at specific stages in the life cycle of a top marine predator. Female southern elephant seals (n = 23) at Marion Island were sampled sequentially using photogrammetry and three-dimensional models (based on each photogrammetry project) were built for estimation of body mass. Simple equations were applied to obtain mass at critical instances in their life cycle. Marion Island elephant seal mass data was compared to data obtained from physically weighed elephant seals from King George, South Georgia and Macquarie islands. Females from Marion Island are smaller, but their percentage lactation mass loss is similar to females from these other populations. The similarity of percentage mass loss during lactation between different female populations illustrates the accuracy and practicality of the photogrammetric method over a temporal scale. Photogrammetric mass estimation can be used alongside datasets of physically weighed animals and can greatly benefit ecology and life history studies.

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Using ecosystem‐services assessments to determine trade‐offs in ecosystem‐based management of marine mammals

Conservation Biology ◽

10.1111/cobi.13512 ◽

2020 ◽

Vol 34 (5) ◽

pp. 1152-1164 ◽

Cited By ~ 1

Author(s):

Christian Riisager‐Simonsen ◽

Olivia Rendon ◽

Anders Galatius ◽

Morten Tange Olsen ◽

Nicola Beaumont

Keyword(s):

Ecosystem Services ◽

Marine Mammals ◽

Ecosystem Based Management ◽

Trade Offs

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Ecological and Physiological Factors Affecting Brood Patch Area and Prolactin Levels in Arctic-Nesting Geese

The Auk ◽

10.1093/auk/123.2.405 ◽

2006 ◽

Vol 123 (2) ◽

pp. 405-418 ◽

Cited By ~ 3

Author(s):

Jón Einar Jónsson ◽

Alan D. Afton ◽

Ray T. Alisauskas ◽

Cynthia K. Bluhm ◽

Mohamed E. El Halawani

Keyword(s):

Body Condition ◽

The Body ◽

Nest Size ◽

Patch Area ◽

Physiological Factors ◽

Factors Affecting ◽

Chen Caerulescens ◽

Brood Patch ◽

Snow Geese ◽

Ross's Geese

AbstractWe investigated effects of ecological and physiological factors on brood patch area and prolactin levels in free-ranging Lesser Snow Geese (Chen caerulescens caerulescens; hereafter “Snow Geese”) and Ross's Geese (C. rossii). On the basis of the body-size hypothesis, we predicted that the relationships between prolactin levels, brood patch area, and body condition would be stronger in Ross's Geese than in the larger Snow Geese. We found that brood patch area was positively related to clutch volume and inversely related to prolactin levels in Ross's Geese, but not in Snow Geese. Nest size, nest habitat, and first egg date did not affect brood patch area in either species. Prolactin levels increased as incubation progressed in female Snow Geese, but this relationship was not significant in Ross's Geese. Prolactin levels and body condition (as indexed by size-adjusted body mass) were inversely related in Ross's Geese, but not in Snow Geese. Our findings are consistent with the prediction that relationships between prolactin levels, brood patch area, and body condition are relatively stronger in Ross's Geese, because they mobilize endogenous reserves at faster rates than Snow Geese.Factores Ecológicos y Fisiológicos que Afectan el Área del Parche de Incubación y los Niveles de Prolactina en Gansos Nidificantes del Ártico

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Information content of SNR/resolution trade-offs in three-dimensional magnetic resonance imaging

Medical Physics ◽

10.1118/1.3098124 ◽

2009 ◽

Vol 36 (4) ◽

pp. 1442-1451 ◽

Cited By ~ 2

Author(s):

S. Portnoy ◽

S. C. Kale ◽

A. Feintuch ◽

C. Tardif ◽

G. B. Pike ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Information Content ◽

Three Dimensional ◽

Resonance Imaging ◽

Trade Offs

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Inverse Design of 3D Multi-Stage Transonic Fans at Dual Operating Points

Volume 6B: Turbomachinery ◽

10.1115/gt2013-95062 ◽

2013 ◽

Cited By ~ 2

Author(s):

James H. Page ◽

Paul Hield ◽

Paul G. Tucker

Keyword(s):

Design Method ◽

Pressure Ratio ◽

Three Dimensional ◽

Inverse Design ◽

Flow Angle ◽

Trade Offs ◽

Multi Stage ◽

Full Speed ◽

Computational Fluid Dynamics Cfd ◽

Operating Points

Semi-inverse design is the automatic re-cambering of an aerofoil, during a computational fluid dynamics (CFD) calculation, in order to achieve a target lift distribution while maintaining thickness, hence “semi-inverse”. In this design method, the streamwise distribution of curvature is replaced by a stream-wise distribution of lift. The authors have developed an inverse design code based on the method of Hield (2008) which can rapidly design three-dimensional fan blades in a multi-stage environment. The algorithm uses an inner loop to design to radially varying target lift distributions, an outer loop to achieve radial distributions of stage pressure ratio and exit flow angle, and a choked nozzle to set design mass flow. The code is easily wrapped around any CFD solver. In this paper, we describe a novel algorithm for designing simultaneously for specified performance at full speed and peak efficiency at part speed, without trade-offs between the targets at each of the two operating points. We also introduce a novel adaptive target lift distribution which automatically develops discontinuous changes of calculated magnitude, based on the passage shock, eliminating erroneous lift demands in the shock vicinity and maintaining a smooth aerofoil.

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Enzymatic antioxidants but not baseline glucocorticoids mediate the reproduction–survival trade-off in a wild bird

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.2141 ◽

2018 ◽

Vol 285 (1892) ◽

pp. 20182141 ◽

Cited By ~ 7

Author(s):

Stefania Casagrande ◽

Michaela Hau

Keyword(s):

Life History ◽

Body Condition ◽

Redox State ◽

Reproductive Investment ◽

Redox System ◽

Reactive Oxygen Metabolites ◽

Enzymatic Antioxidants ◽

Trade Off ◽

Trade Offs ◽

Nest Provisioning

The trade-off between reproductive investment and survival is central to life-history theory, but the relative importance and the complex interactions among the physiological mechanisms mediating it are still debated. Here we experimentally tested whether baseline glucocorticoid hormones, the redox system or their interaction mediate reproductive investment–survival trade-offs in wild great tits ( Parus major ). We increased the workload of parental males by clipping three feathers on each wing, and 5 days later determined effects on baseline corticosterone concentrations (Cort), redox state (reactive oxygen metabolites, protein carbonyls, glutathione peroxidase [GPx], total non-enzymatic antioxidants), body mass, body condition, reproductive success and survival. Feather-clipping did not affect fledgling numbers, chick body condition, nest provisioning rates or survival compared with controls. However, feather-clipped males lost mass and increased both Cort and GPx concentrations. Within feather-clipped individuals, GPx increases were positively associated with reproductive investment (i.e. male nest provisioning). Furthermore, within all individuals, males that increased GPx suffered reduced survival rates. Baseline Cort increases were related to mass loss but not to redox state, nest provisioning or male survival. Our findings provide experimental evidence that changes in the redox system are associated with the trade-off between reproductive investment and survival, while baseline Cort may support this trade-off indirectly through a link with body condition. These results also emphasize that plastic changes in individuals, rather than static levels of physiological signals, may mediate life-history trade-offs.

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Non-Markovian Quantum Optics with Three-Dimensional State-Dependent Optical Lattices

Quantum ◽

10.22331/q-2018-10-01-97 ◽

2018 ◽

Vol 2 ◽

pp. 97 ◽

Cited By ~ 12

Author(s):

A. González-Tudela ◽

J. I. Cirac

Keyword(s):

Quantum Optics ◽

Spectral Density ◽

Long Range ◽

Photon Energy ◽

Optical Lattices ◽

Cold Atoms ◽

Three Dimensional ◽

Collective Effects ◽

State Dependent ◽

Anisotropic Interactions

Quantum emitters coupled to structured photonic reservoirs experience unconventional individual and collective dynamics emerging from the interplay between dimensionality and non-trivial photon energy dispersions. In this work, we systematically study several paradigmatic three dimensional structured baths with qualitative differences in their bath spectral density. We discover non-Markovian individual and collective effects absent in simplified descriptions, such as perfect subradiant states or long-range anisotropic interactions. Furthermore, we show how to implement these models using only cold atoms in state-dependent optical lattices and show how this unconventional dynamics can be observed with these systems.

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Passive acoustic methods for tracking the 3D movements of small cetaceans around marine structures

10.1101/2020.01.30.926659 ◽

2020 ◽

Author(s):

Douglas Gillespie ◽

Laura Palmer ◽

Jamie Macaulay ◽

Carol Sparling ◽

Gordon Hastie

Keyword(s):

Marine Mammals ◽

New Technologies ◽

Three Dimensional ◽

Tidal Energy ◽

Time Of Arrival ◽

Marine Animals ◽

Tidal Turbines ◽

Wide Range ◽

Tidal Turbine ◽

Passive Acoustic

AbstractA wide range of anthropogenic structures exist in the marine environment with the extent of these set to increase as the global offshore renewable energy industry grows. Many of these pose acute risks to marine wildlife; for example, tidal energy generators have the potential to injure or kill seals and small cetaceans through collisions with moving turbine parts. Information on fine scale behaviour of animals close to operational turbines is required to understand the likely impact of these new technologies. There are inherent challenges associated with measuring the underwater movements of marine animals which have, so far, limited data collection. Here, we describe the development and application of a system for monitoring the three-dimensional movements of cetaceans in the immediate vicinity of a subsea structure. The system comprises twelve hydrophones and software for the detection and localisation of vocal marine mammals. We present data demonstrating the systems practical performance during a deployment on an operational tidal turbine between October 2017 and October 2019. Three-dimensional locations of cetaceans were derived from the passive acoustic data using time of arrival differences on each hydrophone. Localisation accuracy was assessed with an artificial sound source at known locations and a refined method of error estimation is presented. Calibration trials show that the system can accurately localise sounds to 2m accuracy within 20m of the turbine but that localisations become highly inaccurate at distances greater than 35m. The system is currently being used to provide data on rates of encounters between cetaceans and the turbine and to provide high resolution tracking data for animals close to the turbine. These data can be used to inform stakeholders and regulators on the likely impact of tidal turbines on cetaceans.

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Ocean Zooglider: an autonomous vehicle for optical and acoustic sensing of zooplankton and suspended particles

10.5194/egusphere-egu21-8658 ◽

2021 ◽

Author(s):

Sven Gastauer ◽

Jeffrey S. Ellen ◽

Mark D. Ohman

Keyword(s):

Autonomous Navigation ◽

Adaptive Sampling ◽

Marine Mammals ◽

Imaging System ◽

Autonomous Vehicle ◽

Three Dimensional ◽

Marine Snow ◽

Seafloor Topography ◽

Optical Images ◽

Mission Duration

Zooglider is an autonomous buoyancy-driven ocean glider designed and built by the Instrument Development Group at Scripps. Zooglider includes a low power camera with a telecentric lens for shadowgraph imaging and two custom active acoustics echosounders (operated at 200/1000 kHz).&#160; A passive acoustic hydrophone records vocalizations from marine mammals, fishes, and ambient noise.&#160; The imaging system (Zoocam) quantifies zooplankton and &#8216;marine snow&#8217; as they flow through a sampling tunnel within a well-defined sampling volume. Other sensors include a pumped Conductivity-Temperature-Depth probe and Chl-a fluorometer.&#160; An acoustic altimeter permits autonomous navigation across regions of abrupt seafloor topography, including submarine canyons and seamounts. &#160;Vertical sampling resolution is typically 5 cm, maximum operating depth is ~500 m, and mission duration up to 50 days.&#160; Adaptive sampling is enabled by telemetry of measurements at each surfacing.&#160; Our post-deployment processing methodology classifies the optical images using advanced Deep Learning methods that utilize context metadata.&#160; Zooglider permits in situ measurements of mesozooplankton and marine snow - and their natural, three dimensional orientation - in relation to other biotic and physical properties of the ocean water column. &#160;Zooglider resolves micro-scale patches, which are important for predator-prey interactions and biogeochemical cycling.&#160;&#160;

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