Investigating the Fluctuating Asymmetry in the Otolith Characters of Mediterranean Horse Mackerel, Trachurus mediterraneus (Steindachner 1868) Inhabiting Edremit Bay, North Aegean Sea

The fluctuating asymmetry values of four different otolith characters such as otolith size, width, area and perimeter of Mediterranean horse mackerel, Trachurus mediterraneus living in Edremit Bay, North Aegean Sea was investigated to determine whether these species are under environmental stress in their habitat. In this study, 180 fish samples captured by local fishermen and 360 sagittal otoliths collected from these samples were used. When left and right otolit characters such as length, width, area and perimeter are examined, a statistical difference (P<0.05) was found only in the otolith area between the left and right otolith pairs, and this difference was reflected in the asymmetry of the otolith area. The fish samples were divided into eight total size groups and the asymmetry of each size group was evaluated separately and without total length groups. Otolith area showed the highest asymmetry with 2.8425 value while otolith perimeter had the lowest asymmetry with 1.5931 value. It was not found that the fluctuating asymmetry of otolith characters studied in the current study was not correlated with sex of the fish (P>0.05). When the fluctuating asymmetry of otolith characters in T. mediterraneus evaluates, the result is that the number of asymmetric individuals is so high that they may be under stress in the living environmen