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Erin Legacki (Fed)

Erin Legacki has been developing quantitative mass spectrometry methods to measure steroid hormones in different matrices in a multitude of mammalian species since 2014. She joins NIST as a National Research Council fellow to measure steroid hormones in the mucus of fish.

Advanced measurement science provides tools to fully characterize fish reproductive endocrinology which can improve the selection of brood stock and increase aquaculture production. The major marine aquaculture product, Atlantic salmon, has had a decline in production since 2000 due, in part, to a decrease in embryo survival rates. This drop in production contributes to the current United States seafood trade deficit of $14 billion dollars in 2016. Reduced embryo survival is directly linked to gamete quality which is influenced by the endocrine status of adult salmon.  Selecting salmon brood stock for improved fertility is difficult as adults are harvested after gamete collection and are not maintained for multiple breeding seasons. Creating a methodology to measure the endocrine profile of salmon before harvesting gametes would ensure only salmon with superior fertility are used for breeding.

In addition to measuring fish fertility, mucus can be used to measure steroid changes after exposure to endocrine disruptors, providing a non-lethal biomonitoring assay. 

Historic measurements of fish steroids are based on potentially lethal blood or tissue sampling and analyzed using immunoassays, an indirect measurement method, designed to only detect a single hormone. The complexity of endocrine pathways requires the measurement of multiple steroid hormones to impart a complete understanding of how changes in the endocrine profile affect fish fertility. The combined advancement of -omics technologies and use of a unique non-lethal matrix can provide a detailed picture of the endocrine pathways unique to reproductively fit fish.

Other Publications

  • Legacki, E.L, et al., Comparative analysis of steroids in cyclic and pregnant killer whales, beluga whales and bottlenose dolphins by liquid chromatography tandem mass spectrometry.  General and Comparative Endocrinology, Submitted 2019
  • Legacki, E.L., et al., Concentrations of sulphated estrone, estradiol and dehydroepiandrosterone measured by mass spectrometry in pregnant mares. Equine Veterinary Journal, 2019.  DOI:10.1111/evj.13109
  • Legacki, E.L., et al., Steroidogenic enzyme activities in the pre- and post-parturient equine placenta. Reproduction, 2018. DOI: 10.1530/REP-17-0472
  • Legacki, E.L., et al., Equine fetal adrenal, gonadal and placental steroidogenesis. Reproduction, 2017. DOI: 10.1530/REP-17-0239e
  • Legacki, E.L., et al., Progestin withdrawal at parturition in the mare. Reproduction, 2016. DOI: 10.1530/REP-16-0227
  • Legacki, E.L., et al., The dynamic steroid landscape of equine pregnancy mapped by mass spectrometry. Reproduction, 2016. DOI: 10.1530/REP-15-0547
  • Legacki, E., et al., Porcine Sertoli cell proliferation after androgen receptor inactivation. Biology of Reproduction, 2015, DOI: 10.1095/biolreprod.114.125716


  • Professors of the Future, Office of Graduate Studies, University of California, Davis, 2012- 2013
  • Outstanding Graduate Student Teaching Award, Office of Graduate Studies, University of California, Davis, 2011
  • Austin Eugene Lyons Fellowship, Department of Animal Science, University of California, Davis, 2011-2013
Created March 26, 2019, Updated June 15, 2021