Food habits of the yellow snapper Lutjanus argentiventris (Peters, 1869) (Percoidei: Lutjanidae) in La Paz Bay, Mexico

A total of 304 yellow snapper Lutjanus argentiventris stomachs were sampled bimonthly from April 2003 to April 2004, of which 44% contained food. We identified 54 prey species. From the index of relative importance (IRI), fish eggs (62%), Harengula thrissina (23%), Porichthys margaritatus (3.3%), and Abudefduf troschelii (2.3%) were the prey of greatest importance in its trophic spectrum. In juvenile snappers, the most important preys were unidentified organic matter (32%), the crustacean Upogebia pugettensis (29%), penaeid shrimp (6.5%), and fish eggs (5.2%). The Levin index determined that the diet breadth was low (B_i=0.0002), indicating that it is a specialist predator showing preference for fish eggs and H. thrissina. The same result was found in males (Bi=0.0002) and females (Bi = 0.0009). Although juveniles also showed a low trophic breadth, they preferred unidentified organic matter and U. pugettensis. The Morisita-Horn index showed considerable overlap in diet between genders (Cλ>0.6), though diet overlap was low between juveniles and adults (Cλ<0.2) reflecting feeding habitat differences between them.