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Data from: Ringed seal (Pusa hispida) seasonal movements, diving, and haul-out behavior in the Beaufort, Chukchi, and Bering seas (2011–2017)

Citation

Von Duyke, Andrew; Douglas, David; Herreman, Jason; Crawford, Justin (2021), Data from: Ringed seal (Pusa hispida) seasonal movements, diving, and haul-out behavior in the Beaufort, Chukchi, and Bering seas (2011–2017), Dryad, Dataset, https://doi.org/10.5061/dryad.zpc866t65

Abstract

Continued Arctic warming and sea-ice loss will have important implications for the conservation of ringed seals, a highly ice-dependent species. A better understanding of their spatial ecology will help characterize emerging ecological trends and inform management decisions. We deployed satellite transmitters on ringed seals in the summers of 2011, 2014, and 2016 near Utqiaġvik (formerly Barrow), Alaska to monitor their movements, diving, and haul-out behavior. We present analyses of tracking and dive data provided by 17 seals that were tracked until at least January of the following year. Seals mostly ranged north of Utqiaġvik in the Beaufort and Chukchi Seas during summer before moving into the southern Chukchi and Bering Seas during winter. In all seasons, ringed seals occupied a diversity of habitats and spatial distributions; from near shore and localized, to far offshore and wide-ranging in drifting sea-ice. Continental shelf waters were occupied for >96% of tracking-days, during which repetitive-diving (suggestive of foraging) primarily to the seafloor was the most frequent activity. From mid-summer to early-fall, 12 seals made ~ one-week forays off-shelf to the deep Arctic Basin, most reaching the retreating pack-ice, where they spent most of their time hauled out. Diel activity patterns suggested greater allocation of foraging efforts to midday hours. Haul-out patterns were complementary, occurring mostly at night until April-May when midday hours were preferred. Ringed seals captured in 2011—concurrent with an unusual mortality event (UME) that affected all ice seal species—differed morphologically and behaviorally from seals captured in other years. Speculations about the physiology of molting and its role in energetics, habitat use, and behavior are discussed; along with possible evidence of purported ringed seal ecotypes.

Methods

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This data package contains tracking, haul-out, and dive data collected by Argos-compatible tags attached to 17 free-ranging ringed seals that were analyzed and presented in:

Von Duyke, A. L., Douglas, D. C., Herreman, J. K., & Crawford, J. A. 2020. Ringed seal (Pusa hispida)  seasonal movements, diving, and haul-out behavior in the Beaufort, Chukchi, and Bering seas (2011-2017). Ecology and Evolution, (accepted April 2020).

All tracking tags in this data package (= 15) were manufactured by Wildlife Computers (Redmond, WA, USA). Data were acquired using the Argos System. Dive and haul-out data were extracted from the sensor fields in the raw Argos DS data using Wildlife Computer's DAP Processor 3.0 (Build 434). Two of the 17 seals carried tags built by the Sea Mammals Research Unit (SMRU), as described in the paper referenced above.

Data from the 2 SMRU tags are not in this data package; those data are planned for release at:  https://portal.atn.ioos.us/#metadata/ae1ea78a-2dbf-4294-908c-77580f92d5fd/project

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Usage Notes

Nine ASCII CSV data sets are included in this data package. Contents of each file are described below.

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ringedSeal_NSB_Alaska_vonDuyke_n17_deploymentAttributes.csv

These data document which tags were attached to which seals, where and when. Attributes about the seals are also
included in this file.
....................................................................................................................

Animal_ID                    unique animal ID
PTT                          Argos tag number
deployment_start_UTC         date-time of tag deployment (UTC)
deployment_end_UTC           date-time following the last data collections from free-ranging animal
deployment_fate              alive: seal thought to be alive when data collections ceased; shed: tag likely detached
deployment_end_type          data end: data collections abruptly ended; voltage drop: battery exhaustion likely 
tag_manufacturer_name        Wildlife Computers, https://wildlifecomputers.com
tag_model                    Wildlife Computers tag model: Splash, Spot, Mk10 (Mk10 is a Splash variant)
location_algorithm           Kalman filter processing was used by CLS (aka Argos) for estimating location
animal_sex                   M, F
animal_life_stage            adult, juvenile (based on size and number of claw bands)
animal_mass_kg               animal weight (kg)
CLAW_BANDS                   number of claw bands
LENGTH_STRAIGHT              head to tail straight line length (cm)
LENGTH_CURVED                head to tail length following spine (cm)
GIRTH_AX                     body circumference behind front flippers
CAPTURE_AREA                 sea ice, open water, or ice water mix 
CAPTURE_METHOD               mono-filament net or dip net
attachment_type              glue or flipper
deploy_on_latitude           deployment location latitude
deploy_on_longitude          deployment location longitude
deploy_location              deployment location name
FLIPPER_ID_TAG               flipper ID tag number
FLIPPER_ID_TAG_COLOR         flipper ID tag color
FLIPPER_ID_TAG_SIDE          flipper ID tag side
UME                          yes/no if seal showed symptomatic signs associated with the 2011 UME
AGENCY                       agency, North Slope Borough (NSB) 
CREW                         names of field biologists involved in the capture and tag deployment
PHOTOS                       were photographs taken during tag deployment
ADDITIONAL_NOTES             notes recorded during tag deployment

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ringedSeal_NSB_Alaska_vonDuyke_n17_diveBehavior_Splash.csv

These data are a chronology of dives and surface events recorded as start and end times. For dive events, the maximum
depth attained and a classification of the dive shape (see below) is included.  Not all tags collected these data.

The tag deployed on animal PH2014BW01 in 2014 used the salt-water sensor to detect the end of a dive, while the
remaining tags (deployed on seals in 2016) used the pressure sensor, which is a superior method because sometimes a seal 
can surface without exposing the salt-water switch to air. 
....................................................................................................................

animal_id                    unique animal ID
ptt                          Argos tag number
behaviorType                 type of event: Dive, Surface, or Missing[data]
start_time_UTC               start date-time of event (UTC)
end_time_UTC                 end date-time of event (UTC)
diveDepth_m                  maximum depth attained during dive event (m)
diveShape                    shape of dive (S square, V, or U) *

* Dive shape definitions from the Wildlife Computers DAP user manual:

Tags that perform behavior processing classify dives into one of three simple shapes
(square, V, and U) by assuming the bottom of a dive is any depth reading >= 80% of the 
maximum reading observed for the dive.  If the total duration for the dive is T and the 
total time between the first bottom reading and the last bottom reading is B:

Shape                        Bottom Time
===============================================
Square                       B > 50% T
V                            B <= 20% T
U                            20% T < B <= 50% T

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ringedSeal_NSB_Alaska_vonDuyke_n17_flagged_filteredLocations.csv

These data are a chronology of Argos satellite-tracking locations for each of 17 ringed seals. Seals were tagged
with 2 transmitters (SPLASH and SPOT). Locations from both tags were pooled to generate one track for each seal.
Locations were calculated by Argos using Kalman Filter processing. Error ellipse data are not available because 
all data were acquired using Telnet.

Plausibility of each location was assessed with the Douglas Argos Filter algorithm (Douglas et al. 2012, doi:
10.1111/j.2041-210X.2012.00245.x). The algorithm's filtering decision is documented in the "Deleted_Location"
variable. Hence, to use only those locations that passed the DAF filtering criteria, all records in which
Deleted_Location=1 should be dropped.

Details about the "Argos" variables can be found in the online Argos User's manual: www.argos-system.org/manual
or in PDF format at doi: 10.5066/P9VYSWEH
....................................................................................................................

Animal_Species               ringed seal
Animal_ID                    unique animal ID
PTT                          Argos tag number
Location_Timestamp_UTC       location date-time, UTC
Latitude                     location latitude (WGS84)
Longitude                    location longitude (WGS84)
Deleted_Location             filter flag, implausible location=1, accepted location=0
Location_Class               Argos location class
Location_NOPC                Argos number of plausibility checks passed
Location_IndexQuality        Argos location index (iqx, iqy)
Location_AssumedAltitude     Argos assumed altitude (for deriving location only)
Pass_Messages_N              Argos number of messages collected during satellite overpass
Pass_Messages_gt120dB        Argos number of messages during pass with signal strength >-120 dB
Pass_Messages_BestLeveldB    Argos best message signal strength received during overpass

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ringedSeal_NSB_Alaska_vonDuyke_n17_percentDry_1hr_bins_Splash.csv
ringedSeal_NSB_Alaska_vonDuyke_n17_percentDry_1hr_bins_Spot.csv

These data are a chronology of haul-out behavior binned into 1-hour intervals. The "percent_time_dry" variable is
the proportion (%) of the respective hour during which the salt-water switch was detected in a dry (open) status. These 
data were transmitted in groups of 24, so successful reception of one transmission conveyed data for 1 full day (UTC).

These data are disseminated in 2 files, one for the SPLASH tags that were attached to a seal's back or head, and one
for the SPOT tags that were attached to a seal's rear flipper.
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species                      ringed seal
Animal_ID                    unique animal ID
PTT                          Argos tag number
oneHrBin_start_UTC           start date-time of the respective 1-hour interval (UTC)
percent_time_dry             percent of the 1-hour during which the salt-water switch was DRY

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Tags deployed in 2011, and some in 2014, were provisioned to report dive information that had been summarized over
6-hour intervals prior to transmission. For Wildlife Computer SPLASH and SPOT tags, these binned-data formats are 
commonly referred to as 'histograms'. There were 4 types of histogram data collected (below): 1) dive depth, which
recorded the number of dives that attained depths within each of 14 depth intervals; 2) dive duration, which recorded
the number of dives having durations within each of 14 duration intervals; 3) time-at-depth, which tallied the 
proportion (%) of dive-time spent within 14 depth intervals; and 4) time-at-temperature, which tallied the proportion
of dive-time spent within 14 temperature bins.
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ringedSeal_NSB_Alaska_vonDuyke_n17_diveDepth_histograms.csv
....................................................................................................................

species                      ringed seal
Animal_ID                    unique animal ID
PTT                          Argos tag number
histogram_6hrBin_start_UTC   start date-time of the respective 6-hour interval (UTC)
maxDiveDepth_bin             dive depth interval (character string description, meters)
number_of_dives              number of dives attaining respective bin-depth, during 6-hour period

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ringedSeal_NSB_Alaska_vonDuyke_n17_diveDuration_histograms.csv
....................................................................................................................

species                      ringed seal
Animal_ID                    unique animal ID
PTT                          Argos tag number
histogram_6hrBin_start_UTC   start date-time of the respective 6-hour interval (UTC)
diveDuration_bin             dive duration interval (character string description, seconds)
number_of_dives              number of dives of respective bin-duration, during 6-hour period

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ringedSeal_NSB_Alaska_vonDuyke_n17_timeAtDepth_histograms.csv
....................................................................................................................

species                      ringed seal
Animal_ID                    unique animal ID
PTT                          Argos tag number
histogram_6hrBin_start_UTC   start date-time of the respective 6-hour interval (UTC)
timeAtDepth_bin              depth-bin interval (character string description, meters)
percent_of_time              percent of 6-hour period spent within respective depth bin

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ringedSeal_NSB_Alaska_vonDuyke_n17_timeAtTemperature_histograms.csv
....................................................................................................................

species                      ringed seal
Animal_ID                    unique animal ID
PTT                          Argos tag number
histogram_6hrBin_start_UTC   start date-time of the respective 6-hour interval (UTC)
timeAtTemperature_bin        temperature-bin (character string, degrees Celsius)
percent_of_time              percent of 6-hour period spent within respective temperature bin


Funding

North Slope Borough / Shell Baseline Studies Program

Office of Naval Research, Award: N00014-16-1-3019

North Slope Borough / Shell Baseline Studies Program