Differentiation of Spatial Units of Genus Euthynnus from the Eastern Atlantic and the Mediterranean Using Otolith Shape Analysis

The shape of sagitta otoliths was used to compare individuals little tunny (Euthynnus alleteratus) harvested on board commercial fishing vessels from the coastal areas along Eastern Atlantic, including Mediterranean Sea. Fish sampling and selection designed cover possible seasonal changes tuna size. research encompassed both morphometric analyses left sagittal extracted 504 fish specimens. Four indices (Circularity, Roundness, Rectangularity, Form-Factor) were significantly different between two groups, showing a statistical differentiation clear spatial units. degree divergence even more pronounced rostrum, postrostrum, excisura generated otolith outlines these groups. One group corresponds samples in Northeast Temperate Atlantic Sea (NETAM Area) second off Tropical coast Africa (ETA Area). This study is first use differentiate tunas separate These results could be re-classify previously collected correct time series data collected.