A morphometric study of the otoliths of a population of Pacific hakeMerluccius productuswas conducted to detect developmental instability (DI) related to parasitism by Myxosporeans,Kudoaspp. We report a link between parasitism and DI, which we measured as fluctuating asymmetry by comparing the right–left differences in otolith shape, width, and weight in the same fish. Otolith shape provided the most sensitive measurement of DI asymmetry. Results suggest thatKudoaspp. could be a strong agent of selection in the Pacific hake.