Possible chemical causes of skeletal deformities in natural populations of Aphanius fasciatus collected from the Tunisian coast

► Patterns of skeletal deformities were detected in natural population of Aphanius fasciatus. ► The high incidence of spinal deformities was observed in the most polluted site. ► The most polluted site is contaminated mainly by heavy metals and organic compounds. ► Relation between the observed deformities and chemical pollution was suggested.