An ecosystem sentinel for the northeast Pacific Ocean twilight zone
Data files
Nov 13, 2024 version files 164.84 MB
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DemYrWide.csv
7.46 KB
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GainIndWide.csv
4.57 KB
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MarkRecap.csv
33.86 KB
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NESE_ALL_DiveStatType_5.txt
164.79 MB
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OceYrWide.csv
3.70 KB
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PupMomMassIndWide.csv
1.63 KB
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README.md
3.22 KB
Abstract
Despite holding most of the global fish biomass, the open ocean twilight zone (200-1,000 m) is poorly understood due to the difficulty of measuring subsurface ecosystem processes at scale. We demonstrate that a wide-ranging carnivore - the northern elephant seal - serves as an ecosystem sentinel for the open ocean. We linked ocean-basin-scale foraging success with oceanographic indices to estimate twilight zone fish abundance five decades into the past, and into the future. We discovered that small variation in seal foraging success amplifies into large demographic changes in offspring body mass, first-year survival, and recruitment. Further, worsening oceanographic conditions could shift predator population trajectories from current growth to sharp declines. As ocean integrators, wide-ranging predators can reveal the impacts of past and future anthropogenic change on open ocean ecosystems.
Four .csv files contain processed data necessary to reproduce figures and analysis as written in the R code “Cohort Code Analysis 2024_06_17.r”. Note that NA values indicate a missing measurement (e.g., weanling mass was not measured in a certain year).
Description of the Data and file structure
Headers in the .csv files are as follows:
DemYrWide
each row is a cohort
Year = Year of birth for a cohort
FirstYrSurv = Average first year survival (%) for the cohort
FirstYrSurvN = Number of seals from which survival values were calculated
N = Number of seals used to calculate proportion recruited
PropRecruit = The estimated proportion of seals in a cohort that produce their first pup.
PropRecruitLower = Lower credible interval of the estimated proportion of seals in a cohort that produce their first pup.
PropRecruitUpper = Upper credible interval of the estimated proportion of seals in a cohort that produce their first pup.
MeanLRS = Cohort-averaged lifetime reproductive success (# pups born to each recruited female)
LowerLRS = Lower credible interval of lifetime reproductive success (# pups born to each recruited female)
UpperLRS = Upper credible interval of lifetime reproductive success (# pups born to each recruited female)
MassMean = Cohort-averaged mass (kilograms) of weaned female pups born to three-year-old moms
MassLower = Lower credible interval of mass (kilograms) of weaned female pups born to three-year-old moms
MassUpper = Upper credible interval of mass (kilograms) of weaned female pups born to three-year-old moms
MassVar = Variance of mass (kilograms) of weaned female pups born to three-year-old moms
GainIndWide
each row is an individual seal mom
MassGain = Body mass gained during foraging trip (kilograms)
YearWhenTracked = Year that seal moms were instrumented
momID = Unique identifier for seals that were moms
OceYrWide
each row is a year
Year = Year of oceanographic measurements (annual averages)
NPGO = Annual average of North Pacific Gyre Oscillation index
PDO = Annual average of Pacific Decadal Oscillation index
SOI = Annual average of Southern Oscillation Index
PupMomMassIndWide
each row is a mother-pup pair
Weight = Weight of pup measured after weaning from mom (kilograms)
MassGain = Body mass gained during foraging trip (kilograms)
momID = Unique identifier for seals that were moms
animalID = Unique identifier for pups born to individual identified seal moms
Please note that “NA” in cells mean that no data were observed.
MarkRecap
cohort = Cohort number
age = Age for survival metric
Phi = Survival rate from age x to age x+1
years = Year of demographic metric
Lifetime-return
Lifetime-return.PDF is an appendix that contains variation in lifetime detection probability.
NESE_ALL_DiveStatType_5
each row is a dive
TOPPID = Individual identifier for each deployment
Year = Year of the dive
JulDate = Julian date of the dive, in MATLAB format
DiveNumber = Sequential number of each dive for each TOPPID
Maxdepth = Maximum depth of each dive, in meters
DiveTypeName = Name of the dive type (Transit, Foraging, etc)