CARNIVORY VS HERBIVORY IN JUVENILE PENAEUS-SETIFERUS (LINNAEUS) AND PENAEUS-AZTECUS (IVES)

Postlarval Penaeus setiferus (Linnaeus), the white shrimp, and Penaeus aztecus (Ives), the brown shrimp, were reared for 24 days on vegetal, animal, and combination diets. Incremental weight change was used to compare shrimp growth rates among dietary treatments. Both species grew most quickly when fed a combination diet. Shrimp fed an animal diet also grew, but those fed vegetal diets either did not survive or grew very little. There were significantly differences between the relative responses of the two species. Brown shrimp fed an animal diet of Artemia grew significantly more than did the white shrimp. Furthermore, the diatom Skeletonema was capable of producing growth in white shrimp that was similar to that produced by an Artemia diet until Day 20, but shrimp fed this vegetal diet did not survive until Day 24. There was no difference in the growth between white and brown shrimp fed a combination diet. The differences between the two species in their ability to utilize plant and animal material can be related to the resources available at their times of immigration.