Steller sea lion pup plasma metabolites

Geographic differences in population growth trends are well-documented in Steller sea lions (Eumetopias jubatus), a species of North Pacific pinniped listed under the U.S. Endangered Species Act in 1990 following a marked decline in population abundance that began during the 1970s. As population growth is intrinsically linked to pup production and survival, examining factors related to pup physiological condition provides useful information to management authorities regarding potential drivers of regional differences.  During dam foraging trips, pups predictably transition among three fasting phases, distinguished by the changes in the predominant metabolic byproduct. We used standardized ranges of two plasma metabolites (blood urea nitrogen and β–hydroxybutyrate) to assign pups to fasting categories (n=1528, 1990–2016, 12 subpopulations): Recently Fed–Phase I (digestion/assimilation–expected hepatic/muscle glycogen usage), Phase II (expected lipid utilization), transitioning between Ph...,
Steller sea lion pups were captured live on their natal rookeries. They were restrained physically or chemically. Blood samples were drawn from the vein of the caudal gluteal plexus into blood tubes with anticoagulants (ethylenediaminetetraacetic acid or sodium heparin). During field physical examinations, morphometrics (mass, standard length, axillary girth) and sex were recorded for most pups, as well as any observed external abnormalities. Blood samples were kept chilled in the field until centrifuging (3000–3500 rpm for ten minutes), typically within four hours of collection. Plasma aliquots were stored at -20°C during the remainder of the field research trips (3–10 days) and at -80°C thereafter (months to years, maximal interval of 8 years) following return to the laboratory.
Plasma-derived [BUN] and [β-HBA] were measured via spectrophotometer (SpectraMax 340PC384, Molecular Devices, San Jose, CA) using commercially-available endpoint assay kits: [BUN] via StanBio Kit #2050 and Si..., , # Steller sea lion pup plasma metabolites

[https://doi.org/10.5061/dryad.66t1g1k76](https://doi.org/10.5061/dryad.66t1g1k76)
**The data are organized into 10 columns:**
 
PupID                         a unique identifier for each Steller sea lion pup
 
CaptDate                  date of capture and sampling: month/day/year
 
BroadRegion            one of four geographic regions in which the pup was born:  Russia,
Aleutian Islands, Gulf of Alaska, Southeast Alaska
 
Subpopulation         one of 12 subpopulations where the pup was born:  4 within Russia (Sea of Okhotsk, Kuril Islands, Kamchatka Peninsula, Commander Islands); the Aleutian Islands (3) and Gulf of Alaska (3) are each divided into western, central, and eastern sections; and Southeast Alaska is separated into southern (historical rookeries) and northern (relatively newly-established rookeries) sections
 
Sex                              sex of the pup:  male, female
 
Mass\_kg                    mass of the pup recorded at ti...