Feeding habits of the snapper Lutjanus peru in the central Gulf of California

A biological basis for survival and development, the diet of fish represents a baseline for research on ecological aspects related to the structure and function of marine communities. This study focused on the feeding habits of the Pacific red snapper, Lutjanus peru, in Santa Rosalía, Baja California Sur (Mexico), during August 2016 through October 2017. A total of 403 specimens were analyzed and categorized by sex, sexual maturity, and season. The size interval ranged from 21 to 60 cm total length, and the weight ranged from 195 to 1,920 g. A total of 29 prey items were identified, including fish (13 items), crustaceans (11 items), mollusks (4 items), and tunicates (1 item). According to the index of relative importance, the main prey were Sardinops sagax (47.65%), Nycthiphanes simplex (38.50%), Harengula thrissina (11.21%), Myctophidae (0.68%), and Benthosema panamense (0.52%). Prey were consumed in different proportions according to sex (F = 2.01, P < 0.049), sexual maturity (F = 4.99, P < 0.001), and season (F = 45.52, P <0.001). The trophic width was narrow (B_i = 0.16); this was consistent with the Costello graph, which showed the consumption of mainly pelagic-coastal and mesopelagic gregarious prey. The Pacific red snapper in Santa Rosalía functioned as a tertiary consumer. Its opportunistic diet included few highly abundant prey items, and the diet composition differed from that of L. peru in other areas of the Gulf of California and the Pacific coast of Mexico.