Biotic communities and feeding habits of Litopenaeus vannamei (Boone 1931) and Litopenaeus stylirostris (Stimpson 1974) in monoculture and polyculture semi-intensive ponds

Zooplankton, macrozoobenthos and feeding habits of Litopenaeus stylirostris and L. vannamei in monoculture and polyculture semi-intensive experimental ponds were evaluated. Zooplankton was more abundant in monoculture of L. stylirostris (1002 +/- 670 organisms (org.) L-1) than in monoculture of L. vannamei (470 +/- 37 org. L-1), and polyculture (321 +/- 188 org. L-1). The main zooplanktonic groups were polychaeta larvae, nauplii, copepods and polychaeta. Macrozoobenthos was more abundant in polyculture (6898 +/- 11 137 org. m(-2)) compared with monoculture of L. stylirostris (3201 +/- 350 org. m(-2)) and L. vannamei (2384 +/- 3752 org. m(-2)). The main benthic groups were copepods, polychaeta, ostracods, nematodes and insects. Differences in feeding habits were found between species and regimes. Litopenaeus vannamei showed to be a more voracious species and fed mostly on organic detritus and benthos in both culture regimes. Litopenaeus stylirostris had a more restricted sources of feed in the ponds. The major component in the stomach content of both species was detritus. Macroalgae, sand, exuvia, formulated feed, prey and microalgae were minor components for both species (< 7%). Ingestion of formulated feed was < 4% for L. stylirostris and was not detected for L. vannamei. The stomach repletion rates were larger for L. vannamei (55.6% and 48.8%) than for L. stylirostris (43.75% and 44.89%). Litopenaeus stylirostris grew better in polyculture (10.3 +/- 3.4 g) that in monoculture (9.0 +/- 3.8 g). Litopenaeus vannamei grew better in monoculture (16.1 +/- 4.8 g) than in polyculture (13.4 +/- 4.5 g). For both species, feed conversion ratio was lower in polyculture.