Histopathological indicators in fish for assessing environmental stress

We present the usefulness of histological and histopathological techniques as tools for evaluation of fish health. Stress at the individual level is frequently presented in the form of tissue damage and we are interested in the study of this level as a health indicator, since it is intermediate between the biochemical and reproductive levels. In addition, we analyzed two case studies conducted using the viviparous fish Goodea atripinnis, the first about the health status by size class of the fish species in the Yuriria Lake, which is affected by a complex mixture of xenobiotics from agriculture, industry, and wastewater, and the second about chronic exposure to a herbicide based on glyphosate. In both cases, various anomalies were found in the liver (fibrosis, cellular disorganization, hemorrhages and vacuoles, pyknosis, and cell lysis), and gills (lamellar fusion, sloughing, hypertrophy, hyperplasia, and leukocyte infiltration). Both studies demonstrated the utility of fish as sentinel organisms and histopathological analysis as a useful tool in environmental biomonitoring to detect early warning signals in aquatic environments.