Histological and Behavioral Toxicity of Tributyltin in the Tropical Guppy Poecilia vivipara

The tropical estuarine guppy Poecilia vivipara was used to address fish early life stage toxicity caused by the antifouling contaminant tributyltin. Six‐day‐old P. vivipara were exposed for 7 d to control water and waterborne tributyltin at 15.8, 83.8, 716, and 818 ng tin (Sn) L–1. After exposure, swimming, feeding, growth, and eye histological endpoints were evaluated. Histopathological analysis of the retinal pigment epithelium (RPE) indicated alterations in pigment positioning at all tributyltin concentrations. A dose‐dependent increase in photoreceptor layer disorganization and iris melanin hyperpigmentation was verified, and high frequencies of RPE invaginations and iris epithelial cell atrophy were observed even at the lowest exposure concentration of 15.8 ng Sn L–1. At the highest exposure level (818 ng Sn L–1) fish also presented reductions in swimming speed, swimming resistance, daily capture of Artemia nauplii, and growth in weight of 85, 60, 33, and 56% relative to controls, respectively. This association between retinal histopathology and reduced swimming and foraging behavior can reduce recruitment to the adult population. Environ Toxicol Chem 2020;39:1953–1963. © 2020 SETAC