Caudal fin malformation in Saurida lessepsianus Russell, Golani & Tikochinski, 2015 collected from Gökova Bay, Aegean Sea, Türkiye

Abstract

One specimen of S. lessepsianus Russell, Golani and Tikochinski, 2015, with 296 mm TL showing caudal fin anomaly, was collected using a gill net from the Gökova Bay, Aegean Sea, at 52 meters of depth. The lower three fin rays were deformed in the caudal fin's lower lobe. The length of the lower lobe of the tail of the abnormal fish is 75.6% of the length of the upper lobe of the abnormal fish, while it is 76.5% in the normal specimen. Possible reasons that could cause this abnormality, such as viral or bacterial infection or environmental pollution, are discussed. Since the anomaly was observed in a single specimen and not a frequent state in other fish within the studied area, spontaneous genetic mutation was also considered. The present finding represents the first record of caudal fin-deformed wild fish, S. lessepsianus, from the southeastern Aegean Sea ever reported and highlighted the need for closer monitoring of the marine environment for the identification of the specific factor that caused this abnormality.