Data and code from: You shall not pass, the Pacific oxygen minimum zone creates a boundary to shortfin mako shark distribution in the Eastern North Pacific Ocean
Data files
Sep 10, 2024 version files 4.06 MB
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AtlanticArgos.csv
2.13 MB
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Pacific_TAD.csv
238.32 KB
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PacificArgos.csv
1.69 MB
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README.md
2.47 KB
Abstract
Shoaling of large oxygen minimum zones (OMZs) that form along eastern margins of the world’s oceans can reduce habitat availability for some pelagic fishes. Our aim was to test the hypothesis that habitat compression caused by shoaling of the Pacific OMZ in tropical regions creates a boundary to the southern distribution of shortfin mako sharks (Isurus oxyrinchus) in the Eastern North Pacific Ocean.
README: Data and code from: You shall not pass; the Pacific oxygen minimum zone creates a boundary to shortfin mako shark distribution in the Eastern North Pacific Ocean
https://doi.org/10.5061/dryad.2rbnzs7vm
Satellite tracking data for mako sharks in the Eastern North Pacific and Western North Atlantic Oceans, as well as environmental data and R code for simulating tracks.
Description of the data and file structure
AtlanticArgos.csv; Raw Argos data for mako sharks in the Atlantic, with columns:
id = track id
date = date and time (UTC) of Argos detections
lc = Argos location class (3,2,1,0,A,B)
lon = longitude
lat = latitude
PacificArgos.csv; Raw Argos data for mako sharks in the Pacific, with columns:
id = track id
date = date and time (UTC) of Argos detections
lc = Argos location class (3,2,1,0,A,B)
lon = longitude
lat = latitude
Track_Simulation_Analysis_Code.R = R code for simulating tracks and recreating the analysis of avoidance of the Pacific OMZ
Mako_DATA.RData = an R workspace containing data objects including:
12 Monthly Raster Brick objects with SST, Ocean Heat Content, and Dissolved O2 at 100m (JanR, FebR, etc.)
Atl.SSM = Data frame of daily SSM location estimates for Atlantic Sharks
Pacific.SSM = Data frame of daily SSM location estimates for Pacific Sharks
Atl.samples = Data frame of 100 random daily MCMC samples from SSM locations for Atlantic sharks
PacFemale.samples = Data frame of 100 random daily MCMC samples from SSM locations for female Pacific sharks
PacMale.samples = Data frame of 100 random daily MCMC samples from SSM locations for male Pacific sharks
Simulation.Data = Data frame of daily locations and habitat variables for simulated tracks
simulation.summary = Data frame of summarized count of days over the Pacific OMZ for real and simulated tracks
Pacific_TAD.csv; Time at depth data for make sharks in the Pacific during days with SLRT and PAT available. Columns include:
id = shark id
PAT_PTT = PAT tag id
spot_tt = SLRT id
Date = Date
B_50 = proportion of time between 0 - 50m
B100 = proportion of time >50 - 100m
B150 = proportion of time >100 - 150m
B200 = proportion of time >150 - 200m
B_200 = proportion of time > 200m
lon = longitude
lat = latitude
SST = sea surface temperature (Celsius)
DO_depth = Hypoxic boundary depth (m), where dissolved oxygen concentration is 3.0 ml/l
Code/Software
All analyses were run in R v4.2.2
Methods
Satellite tagging of shortfin mako sharks captured in long line or sportfishing equipment in the northwest Atlantic (2013 - 2020) and northeast Pacific (2003-2016) Oceans. Sharks were tagged with fin-mounted satellite-linked radio tags (SLRT), and a subset of sharks in the Pacific were also tagged with pop-up archival tags (PAT).
Location
Eastern North Pacific and Western North Atlantic oceans.
Methods
We compared environmental conditions between areas used by satellite-tagged mako sharks in the Eastern North Pacific, encompassing the world’s largest OMZ, to those used in the Western North Atlantic where no OMZ is present. In the Pacific we quantified the effects of temperature and dissolved oxygen (DO) on depth use and tested if sharks spent less time in areas with strong habitat compression over the OMZ than expected by chance.
Results
The southern distribution of sharks in the Pacific corresponded with the apex of OMZ shoaling in the North Equatorial Current. Sharks in the Atlantic occupied areas with warm surface temperatures (≥ 26oC) more often than the Pacific, and waters with these temperatures in the Atlantic had greater DO at depth. Sharks in the Pacific reduced time near the surface in warm temperatures and consistently avoided depths with low DO and spent less time in areas with strong habitat compression than expected by chance.
Main Conclusions
The combination of warm surface temperatures and shoaling of the OMZ creates a soft boundary to mako shark movements in the Eastern North Pacific Ocean. The expected expansion of OMZs due to climate change could have considerable impact on future distribution of mako sharks and other pelagic fish. As such, development of species distribution models to predict effects of climate change on pelagic fish distributions should incorporate oxygen availability.