Volterra also had a daughter, Luisa Volterra, who married Umberto d'Ancona. D'Ancona piqued his father-in-law's interest in biomathematics when he showed Vito a set of data regarding populations of different species of fish in the Adriatic Sea, where decreased fishing activity from the war had led to an increase in the populations of predatory fish species. Vito published an analysis of the dynamics of interacting species of fish the next year.