A novel and versatile flash-freezing approach for evaluating the health of Delta Smelt

Swee J. Teh, Dolores V. Baxa, Bruce G. Hammock, Saikrithika A. Gandhi, Tomofumi Kurobe

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


A common approach used to assess environmental impacts in aquatic environments is to measure indicators of stress (biomarkers) and condition of fish within ecosystems. Particularly in estuarine ecosystems with multiple stressors, it is often desirable to quantify a suite of biological endpoints that (1) reflect fish condition at several levels of biological organization and time scales and (2) are sensitive to a range of environmental stressors. However, established methods of preservation and processing of fish for specific endpoints are often incompatible. Here, we developed a novel flash-freezing approach for assessing the health of a small, sensitive fish, the endangered Delta Smelt ( Hypomesus transpacificus) after collections from the San Francisco Estuary (SFE). We assess whether flash-freezing the entire fish ensures effective preservation of multiple tissues for subsequent biomarker analyses by comparing measurements of fresh to frozen tissue. Tissues included brain, gill, and liver for enzyme activity, kidney and spleen for pathogens, and gills, liver, and gonads for histopathology and reproduction. Although flash-freezing in liquid nitrogen altered the length, weight, and condition factor of Delta Smelt, the percent changes were small (

Original languageEnglish (US)
Pages (from-to)152-161
Number of pages10
JournalAquatic Toxicology
StatePublished - Jan 1 2016


  • Biomarker
  • Delta Smelt
  • Flash-freezing
  • Necropsy
  • San Francisco Estuary

ASJC Scopus subject areas

  • Aquatic Science
  • Health, Toxicology and Mutagenesis


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