Skeletal deformities in the invasive pumpkinseed sunfish (Lepomis gibbosus) inhabiting Turkish inland waters

This investigation provides the first documented evidence of spinal pathologies in a wild population of the teleost Lepomis gibbosus from a freshwater habitat in Türkiye. The primary objective was the comprehensive diagnosis and characterization of skeletal deformities to establish a reference baseline for future ecotoxicological and biomonitoring studies. High-resolution mammography enabled the identification and classification of anomalies into two distinct groups. Major abnormalities included vertebral coalescence, hypural deformation, and abdominal rib deformation. Minor deformities comprised caudal fin ray, hemal spine, and parhypural bone deformities. The consistent ‘containment’ pattern of vertebral fusion, among other anomalies, suggests developmental disruption and supports the utility of this species as a bioindicator. This work provides a critical reference for identifying specific environmental stressors in freshwater ecosystems and for monitoring ecosystem health.