For fish in an advanced state of digestion, we used the keys of Clothier (1950) and Miller & Jorgensen (1973). The fish skeleton collection from the Laboratorio de Ecología de Peces del Centro Interdisciplinario de Ciencias Marinas (CICIMAR) at La Paz, Mexico, was useful for prey verification. Crustaceans were identified using Brusca (1980) and Fischer et al. (1995). Worms were identified with Bastida (1991), and cephalopods with Iverson & Pinkas (1971).