• Blood analysis is a valuable tool to assess fish health. • Baseline levels in Tilapia are relevant for environmental biomonitoring programs. • Baseline parameters can facilitate data comparison after experimental conditions. • Alternative pathways can be used as a biomarker after pollutant exposure. • Acute and chronic exposure to pollutants alter blood analysis parameters.

The biodiversity of marine and coastal ecosystems is constantly threatened by pollutants from a diversity of human activities. The polycyclic aromatic hydrocarbons (PAHs) are a class of pollutants widely released and deposited in these environments, leading to several impacts on the community of organisms that integrate these ecosystems. As lipophilic compounds, PAHs become bioavailable to organisms and can enter the trophic chain, leading to physiological changes and affecting different levels of biological organization. Several studies demonstrate that PAHs act as endocrine disruptors in marine fish, interfering with endocrine signaling through hormonal disturbances and, consequently, causing inhibition or overexpression of genes, enzymes, and proteins that are essential for reproduction success. These changes, in turn, can lead to population decline and cause immeasurable ecosystem damage. This review synthesizes studies published mainly between 2015 and 2025, aiming to critically present research that identifies different endocrine-reproductive changes in marine fish species exposed to PAHs in contaminated sites, highlighting the involved cellular mechanisms. Finally, we provide a survey of patents developed to identify PAHs in aquatic environments and how these techniques can be used in marine biomonitoring to evaluate water quality and the risk of exposure to biota and human populations.