Scanning electron microscopy comparison of an abnormal and normal otoliths of the Anguilla anguilla collected from the Bafa Lake in Western Anatolia

Abstract

Aberrations in the otolith can harmfully influence the imperative actions of the fish species. The chief drive of the current investigation is to describe the deformities in the otoliths of the European eel Anguilla anguilla. Out of 76 Anguilla anguilla individuals collected from Bafa Lake in Western Anatolia, Türkiye, four female specimens exhibited abnormal otoliths. Scanning electron microscope was used to determine the deformed otoliths examined. The outcomes of the abnormality analyses in A. anguilla otoliths, deformities were noticed such as numerous prominence structures and bumps of different sizes on the surface of the otolith produced by buildup of the different crystal structures in some parts of the otolith. These deformities were found in the left and/or right otoliths of the female individuals of different total lengths. The percentage of individuals with abnormal otoliths of A. anguilla is calculated as 5.3%. The current study presents for the first-time abnormal otolith information on left and right otoliths in female A. anguilla. Deformities in the otoliths of European eels are believed to result from a combination of genetic predisposition and stress caused by various environmental factors, such as water pollution, changes in salinity, temperature fluctuations and nutritional imbalances.