Fluctuating asymmetry as a measure of ecological stress in Trachurus trachurus (Linnaeus, 1758)

Abstract

Fluctuating asymmetry (FA), the small and random deviations from perfect symmetry in an organism’s bilateral traits, has been used as a measure of developmental stability and an indicator of stress in Trachurus trachurus populations. This study assessed the variations in FA levels between samples. An increase in FA values was observed as the fish grew. Mature males and females, respectively, showed higher stress levels than the immature fish in the study of sexual variations of FA. The study also revealed that individuals collected in the Mediterranean were more stressed than those collected in La Ria de Vigo, and that individuals harvested in winter and summer were more stressed than those caught in spring. Temperature is a key environmental factor for T. trachurus. This fish functions optimally within a very narrow temperature range, and deviations from this range could induce stress during development.