Distribution of two post-larvae species of commercial prawns (Fenneropenaeus indicus and Penaeus monodon) in a coastal tropical estuary

Abstract

The white prawn, Fenneropenaeus indicus, and the tiger prawn, Penaeus monodon, are of great commercial importance, and they are extensively farmed along the eastern coast of India. Post-larvae of these species coexist in great abundance in estuaries along the Bay of Bengal. In this investigation, field distribution, habitat selection and stomach contents were analyzed in these two prawn species. Field sampling and laboratory studies revealed significant differences in their habitat and diet selection patterns of experimental populations. Post-larvae were collected bimonthly at two stations: (A) bare rocky flats and (B) sandy bottom bordered by mangrove vegetation. Station A was dominated by P. monodon (78.8%); station B was mostly represented by F. indicus (83.6%). Both species showed little variation in their field percentages during the sampling months between July and November 1996. In a laboratory setting, regardless of whether the species were single or mixed together, P. monodon selected rocky habitats (83%) over sand, and F. indicus showed strong selection for sandy substrate (86%). Stomach content analyses revealed phytoplankton to be the prawns' most abundant dietary item. Microalgal cells formed the major dietary component in F. indicus (60%), while P. monodon was found to consume primarily filamentous algae (65%). Such differential habitat and diet selection behavior may possibly reduce competition between these prawn species in the field.

JOURNAL OF AQUATIC SCIENCES Volume 16, Number 2, October 2001, pp. 99-104




KEY WORDS:

Fenneropenaeus, Penaeus, post-larvae, habitat, diet