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Se revisaron 108 estómagos del tiburón Heterodontus francisci Girard, 1854, capturados en Laguna San Ignacio, Baja California Sur, en muestreos trimestrales de enero de 1992 a febrero de 1993. Esta especie se encuentra en la laguna durante todo el año, disminuyendo su abundancia durante las estaciones de verano y otoño. De acuerdo con el índice de importancia relativa (IIR), el tiburón se alimenta de los siguientes invertebrados bentónicos: gasterópodos (Lucapinella milleri y Calyptraea spp.), crustáceos (Callinectes bellicosus, Penaeus spp. e isópodos), pelecípodos (no identificados), sipuncúlidos (Sipunculus nudus), cefalópodos (Octopus spp.), así como de peces pequeños (Syngnathus auliscus). Heterodontus francisci es un consumidor de tercer orden, ya que es una especie bentónica, predominantemente carnívora, que se caracteriza por ser un depredador selectivo de hábitos nocturnos y/o crepusculares. A total of 108 stomach contents of horn shark (Heterodontus francisci Girard, 1854) from San Ignacio Lagoon were analyzed. The samples were taken seasonally from January 1992 to February 1993. This species occurred all year round, with low abundance in summer and fall. The index of relative importance (IRI) was used to determine the prey importance. The horn shark feeds mainly on benthic invertebrates, such as gastropods (Lucapinella milleri and Calyptraea spp.), crustaceans (Callinectes bellicosus, Penaeus spp. and isopods), pelecypods (unidentified). sipunculoids (Sipunculus nudus), cephalopods (Octopus spp.), as well as on small fishes (Syngnathus auliscus). This shark is a third-order consumer, because it is a predominantly carnivorous benthic species: it is a selective predator with nocturnal or crepuscular habits.

The analysis of the stomach contents of 500 dolphinfish Coryphaena hippurus is presented. The fish were caught from the shoreline to 25 miles off Cabo San Lucas, Baja California Sur, Mexico. Fifty-one prey were identifíed from the food items of the dolphinfish, which pertain to three categories: fishes, cephalopods and crustaceans and, according to the index of relative importance, represent 56.3%, 23.1% and 20.6%, respectively. Of the 51 prey, 18 represented 97%. Dosidicus gigas, Pleuroncodes planipes, Balistes polylepis. Cypselurus callopterus and Auxis spp. contributed 70% of the food supply. The dolphinfish is characterized as a top predator or a highly voracious organism with a wide trophic spectrum. Its food habits tend to be closely related to the epipelagic environment.