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 (bi=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.