DOI: 10.6084/m9.figshare.28517873.v1
title: <b>Penguins Exploit Tidal Currents for Efficient Navigation and Opportunistic Foraging: </b><b>Ocean Currents (U and V Components from ROMS) and Penguin Biologging Data from San Lorenzo Gulf, Argentina (2019). </b>

description: Datasets and R script wrokflow for Penguins Exploit Tidal Currents for Efficient Navigation and Opportunistic Foraging.The two main dataframes from which all analysis was conducted are:<b>Ocean_Currents.csv </b>The matlab equivalent (<b>mat_uv_peng_extarea1.mat</b>), utilised in '<b>Workflow script.R</b>' is also supplied. This is vertically-averaged ocean current U/V components (m/s) from a ROMS simulation of the San Matías Gulf, hourly from 22 Nov 2019 for 240 hours.<br>and <b>Penguins.csv. </b>This is High-resolution movement and behavioral data from GPS- and sensor-equipped Magellanic penguins (Spheniscus magellanicus) foraging in the San Matías Gulf (Peninsula Valdés, Argentina), 22 Nov – 1 Dec 2019.Other data files correspond to data underlying various figures/analysis. More information can be found in 'Workflow script.R'.<br><b>Ocean_Currents.csv</b> --&gt; This dataset contains simulated ocean current data for the San Lorenzo Gulf, derived from the Regional Ocean Modeling System (ROMS). The dataset provides vertically averaged current velocities in the U (East-West) and V (North-South) components over a discretized spatial grid. Time series data are included at hourly intervals, spanning November 22, 2019, across 240 time steps. The dataset is structured to support analyses of current dynamics in relation to movement strategies of tagged Magellanic penguins, foraging in this area during this time.<br><br><b>Data Collection & Model Description:</b><br><b>Model Used:</b> Regional Ocean Modeling System (ROMS)<b>Grid & Coordinates:</b>Horizontally: <b>Orthogonal curvilinear grid (Arakawa C-grid)</b>Vertically: <b>Terrain-following stretched coordinates</b><b>Forcing & Boundary Conditions:</b>Tidal amplitudes and phases interpolated from the <b>TPXO6</b> global tidal model<b>Eight principal tidal constituents</b> (M₂, S₂, N₂, K₂, K₁, O₁, P₁, Q₁), plus additional long-term and higher harmonicsOpen boundaries: <b>South, West, and North</b><b>Vertical Mixing Scheme:</b> Mellor-Yamada parameterization<b>Bathymetry:</b> Derived from <b>digitized nautical charts</b><b>Harmonic Analysis & Data Processing:</b>Instantaneous (3D) current outputs underwent <b>harmonic decomposition</b> to extract <b>dominant tidal constituents</b> (M₂, S₂, N₂).<b>Phase adjustments</b> applied using the <b>XTide model</b> (https://flaterco.com).The U (zonal) and V (meridional) velocity components were <b>vertically averaged</b>, as <b>no significant depth-dependent variation</b> was found within the study area.<b>Spatial & Temporal Coverage:</b><b>Study Region:</b> <b>San Lorenzo Gulf</b>, <b>Patagonia, Argentina</b><b>Time Span:</b> November 22, 2019- December 02, 2019<b>Grid Resolution:</b> Matches ROMS model spatial resolution<b>Depth Consideration:</b> Vertically averaged currentsThe model setup follows <b>Tonini & Palma (2017) </b>for grid, forcing, and validation details.[Tonini, M.H. and E.D. Palma, Tidal dynamics on the North Patagonian Argentinean Gulfs. Estuarine, Coastal and Shelf Science, 2017. 189: p. 115-130.].<br><b>Penguins.csv --&gt;</b> This dataset contains <b>high-resolution movement and behavioral data</b> from <b>Magellanic penguins </b>(<i>Spheniscus magellanicus</i>) tracked in the <b>San Lorenzo Gulf, Patagonia, Argentina, during 2019</b>. The data were processed from <b>bio-logging devices</b>, which recorded GPS, acceleration, magnetometry, and depth information, enabling reconstruction of the penguins' kinematics, behavior, and estimated GPS-corrected dead-reckoned (DR) positions.Fieldwork was conducted between 22 November and 1 December 2019 at the San Lorenzo Magellanic penguin colony, Peninsula Valdés, Argentina (42.08° S, 63.86° W). We selected 27 adult Magellanic penguins (Spheniscus magellanicus) brooding small chicks for this study. Each penguin was equipped with a GPS logger (AxyTrek, Technosmart, Italy) and a Daily Diary (DD) logger. The GPS units recorded positions at 1 Hz, while the DD loggers recorded tri-axial acceleration at 40 Hz and tri-axial magnetometry at 13 Hz, and pressure (indicating depth) at 4 Hz. Both devices were housed in hydrodynamic casings designed to minimize drag. Devices were secured on the dorsal midline with Tesa® tape. Penguins completed a single foraging trip before recapture.Ethical approval for the research was granted by Swansea University's Ethics Committee (SU-Ethics-Student: 260919/1894) and the Animal Welfare and Ethical Review Body (AWERB approval: IP-1819-30). Fieldwork permits were authorized by the Conservation Agency of Chubut Province (Disp N° 047/19-SsCyAP; No. 060/19-DFyFS-MP). All procedures involving penguin handling were reviewed and approved by the Dirección de Fauna y Flora Silvestre and the Ministerio de Turismo y Áreas Protegidas de la Provincia de Chubut.This dataset is sub-sampled to 1 Hz per penguin. All smoothed variables ('_sm') had 2 s centre-aligned rolling means applied (circular mean for heading).The dataset includes <b>timestamped movement variables</b>, behavioral classifications, and GPS-corrected dead-reckoned locations for the tracked individuals. These data were used to analyze <b>penguin foraging behavior</b> and <b>navigation strategies, </b>in relation to ocean currents (see associated dataset "Ocean_Currents.csv"). <b>Dataset Contents & Column Descriptions [Penguins.csv]:</b>The dataset is stored as a <b>CSV file</b> (Penguins.csv), with the following <b>columns</b>:<b>Column Name:</b> Description<b>DateTime</b> UTC timestamp of each record (YYYY-MM-DD HH:MM:SS)<br><b>ID</b> Unique penguin identifier<br><b>VeDBA.smoothed</b> Smoothed Vectorial Dynamic Body Acceleration (VeDBA)<br><b>Mag.heading.smoothed</b> Smoothed magnetic (compass) heading in degrees, corrected for sensor offsets<br><b>smth.depth</b> Smoothed dive depth (m), adjusted for sensor drift<br><b>Behaviour.occurrence</b> Cumulated unique Occurence of each behaviour ("dive", "subsurface", "surface")<br><b>Behaviour.Group</b> 'Behaviour' and 'Behaviour.occurrence' values pasted together<br><b>Behaviour.duration</b> Duration (s) of the current behavioral bout<br><b>Behaviour</b> General behavior classification: "dive", "subsurface", "surface"<br><b>corrected.pitch</b> Smoothed body pitch angle (degrees), corrected for sensor bias<br><b>Dive.profile</b> Sub-phase of dive (“Descent”, “Bottom phase”, “Ascent”), otherwise, 'Surface_Sub-surface'<br><b>speed</b> Estimated swim speed estimates (m/s)<br><b>CS</b> Ocean Current Speed (m/s) at the penguin’s location and time<br><b>CH</b> Ocean Current Heading (direction of flow 'towards' in degrees)<br><b>DR.longitude.corr</b> GPS-corrected Dead-reckoned longitude (decimal degrees)<br><b>DR.latitude.corr</b> GPS-corrected Dead-reckoned latitude (decimal degrees)<br><b>DR.straightline.distance.from.start.2D</b> Planar distance (m) from the trip’s starting point, calculated in 2D<br><b>Row.number</b> Original row index in the processing pipeline<br><b>Prey.persuit</b> Occurence of prey-pursuit event<br><b>DR.longitude.corr.m</b> GPS-corrected Dead-reckoned longitude converted to a planar metric projection (meters)<br><b>DR.latitude.corr.m</b> GPS-corrected Dead-reckoned latitude converted to a planar metric projection (meters)<br><b>trip_status</b> Trip phase indicator (e.g., “Outbound”, “Inbound”)<br><b>turns</b> Occurence of 'significant' turns<br><b>Hour</b> Hour of day (0–23)<br><b>Time</b> Time (YYYY-MM-DD HH) extracted from DateTime<br><b>U_comp</b> Zonal (East-West) current velocity component (m/s)<br><b>V_comp</b> Meridional (North-South) current velocity component (m/s)<br><b>index</b> (same as 'Row.number')<br><b>Distance</b> 2D Distance moved (estimated from GPS-corrected dead-reckoned coords)<br><b>Prop.distance.travelled</b> Proportion of distance moved (scaled 0–1)<br><b>Prop.time.travelled </b>Proportion of time into round trip (scaled 0–1)<br><b>Dataset Contents & Column Descriptions [Ocean_Currents.csv]:</b>The dataset is stored as a <b>CSV file</b> (Ocean_Currents.csv), with the following <b>columns</b>:<b>Column Name</b>Description<b>Lat</b>Latitude (decimal degrees, WGS84)<b>Lon</b>Longitude (decimal degrees, WGS84)<b>Hours</b>Time index in hours from model start<b>U_comp</b>Zonal (East-West) current velocity component (m/s)<b>V_comp</b>Meridional (North-South) current velocity component (m/s)<b>Time/TS</b>Timestamp (YYYY-MM-DD HH:MM:SS, GMT)############################<b>Files pertaining to bathymtery data:</b>gebco_08_-67_-45_-62_-40_pertaining_to_Fig.S8a sgdf_bathy_pertaining_to_Fig.S8a<b>Workflow script.R</b> --&gt; R script showing step-by-step data processing, analysis, and figure generation. Note Fig 2 and S2, are constructed directly from Penguins.csv and Fig S1 from Ocean_Currents.csv.