The existence of three different stocks is assumed in the Atlantic Ocean by ICCAT: northern and southern Atlantic stocks and a Mediterranean stock, and it is used for assessment purposes (Winker et al. 2021) (ICCAT 2021). Such division is based on results from different studies highlighting the heterogeneity that may exist within both stocks (northern Atlantic and Mediterranean), such as the independent spawning area existing in the western Mediterranean, different morphometric characteristics, different growth rates and age of maturity, and serological differences (Arrizabalaga et al. 2002).

A significant population structuring seems to be occurring for this species in this particular region (northern Atlantic and Mediterranean), with potential high gene flow within populations (Davies et al. 2011), corroborating previous studies reporting a genetic differentiation (Viñas et al. 2004), which might support possible stock discrimination amongst regions. Here it is assumed a single biological stock for the Mediterranean Albacore.