Blood chemistry and hematologic reference ranges are useful for population health assessment and establishing a baseline for future comparisons in the event of ecosystem changes due to natural or anthropogenic factors. The objectives of this study were to determine if there was any population spatial structure for blood variables of Steller sea lion (Eumetopias jubatus), an established sentinel species, and to report reference ranges for appropriate populations using standardized analyses. In addition to comparing reference ranges between populations with contrasting abundance trends, data were examined for evidence of disease or nutritional stress. From 1998 to 2011, blood samples were collected from 1,231 pups captured on 37 rookeries across their Alaskan range. Reference ranges are reported separately for the western and eastern distinct population segments (DPS) of Steller sea lion after cluster analysis and discriminant function analysis (DFA) supported underlying stock structure. Variables with greater loading scores for the DFA (creatinine, total protein, calcium, albumin, cholesterol, and alkaline phosphatase) also were greater for sea lions from the endangered western DPS, supporting previous studies that indicated pup condition in the west was not compromised during the first month postpartum. Differences between population segments were likely a result of ecological, physiological, or age related differences.
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We thank the entire staff of the Alaska Ecosystems Program at the National Marine Mammal Laboratory (NMML), including P. Brown, V. Burkanov, K. Call, B. Caruso, B. Dickerson, S. Finneseth, L. Fritz, C. Gudmundson, C. Kuhn, R. Ream, J. Sease, J. Sterling, W. Testa, J. Thomason, R. Towell, and T. Zeppelin for all of their assistance with capturing and handling sea lions and for sample collection and processing. We also thank all members of the ADF&G field collections team including A. Baylis, K. Beckmen, R. Braun, K. Burek, J. Crye, C. Eischens, D. Faquier, C. Flatten, T. Haase, M. Haulena, C. Jewett, S. Johnson, C. Kaplan, M. Lambert, J. King, M. Litzow, S. Moore, B. Murphy, G. O’Corry-Crowe, K. Pitcher, M. Rehberg, J. Richmond, E. Schoen, R. Small, G. Snedgen, G. Spencer, V. Stegall, C. Stinchcomb, W. Taylor, D. Tollit, J. Westlund, E. Wilson, K. White, and J. Womble. We further thank J. Baily, E. Boerner, A. Burdin, B. DeLong, F. Gulland, H. Harris, D. Hennen, R. Jenkinson, T. Hobbs, J. Mellish, Y. Miyake, P. Nicklen, S. Norman, J. Scordino, D. Thompson, S. Trumble, V. Vanek, L. Wheeler, B. Wright, and crews of the M/V TIGLAX, M/V PACIFIC STAR, M/V Morning Star, R/V NORSEMAN, R/V MEDEIA, and the AEP field camps for their field support. D. Johnson and H. Smith provided valuable assistance with data analysis, D. Greig (per L. Schwacke) provided some code and advice, and G. Duker, B. Dickerson, S. Norman, and two anonymous reviewers provided constructive comments on the manuscript. This work was supported by the NMML and by NOAA cooperative agreement funding to ADF&G. Sample collections were conducted under the authority of Federal MMPA/ESA Permits 782-1447, 782-1532, 782-1768, 782-1889, and 14326 issued to NMML and permits 358-1564 and 358-1769 issued to ADF&G. The findings and conclusions in the paper are those of the authors and do not necessarily represent the views of the NMFS, NOAA. Reference to trade names does not imply endorsement by the NMFS, NOAA.
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Lander, M.E., Fadely, B.S., Gelatt, T.S. et al. Serum Chemistry Reference Ranges for Steller Sea Lion (Eumetopias jubatus) Pups from Alaska: Stock Differentiation and Comparisons Within a North Pacific Sentinel Species. EcoHealth 10, 376–393 (2013). https://doi.org/10.1007/s10393-013-0891-x
- Eumetopias jubatus
- health status
- nutritional stress
- reference ranges
- serum chemistry
- Steller sea lion