Fish hematology diagnosis as a protocol to evaluate aquatic pollution: Ariopsis felis catfish the Gulf of Mexico, study case.

Abstract

Aquatic pollution is a problem that has increased over time, affecting organisms of biological and commercial importance. Fish are valuable pollution bioindicators, lacking minimal invasive protocols to assess their health. Fish blood is sensitive to environmental stressors and is easy to obtain using minimally invasive and low-cost techniques, making it a powerful tool for monitoring pollution using fish. For this reason, the morphological and cytogenetic changes in erythrocytes serve as pollution indicators in different aquatic bodies, such as coastal areas like the Gulf of Mexico. Accordingly, we generated a protocol to evaluate aquatic contamination through fish hematological diagnosis. Briefly, the protocol consists of the collection of fish and the extraction of their blood. These samples serve to characterize erythrocyte counts and morphology through Giemsa-stained smears. Additionally, comet assays determine the degree of genotoxic damage. Altogether, we generated a hematological status summing the parameters indexes to determine the fish health diagnosis, giving an overall idea of the environmental health status. Particularly, the catfish (Ariopsis felis) from Tecolutla estuarine system presented morphological changes such as poikilocytosis, echinocytosis, hypochromia, variations in nuclear morphology, as well as a moderate-to-high genotoxicity level. These results indicated a moderate and high genotoxic degree and slightly contamination. To sum up, this study endorses the use of minimally invasive protocols, compared to others that require the death of organisms, to assess the health status of aquatic bodies bioindicators. Overall, the protocol developed in this study establishes a health diagnosis based on morphological alterations and genotoxic damage in the erythrocytes of catfish (A. felis) from Tecolutla, Veracruz, Mexico.