The blue shark Prionace glauca is an important fishery resource in Ecuador. A total of 577 organisms between 130-307 cm of total length (TL) was recorded. The sex ratio was 1.06 males: 1 females. In males, the clasper length was between 4 to 21.2 cm and the inflection point was estimated at 189.7 cm TL. The mean size at maturity (TL50) for male blue sharks was 187.1 cm TL.