Habitat usage by postlarval and juvenile prawns in Moreton Bay, Queensland, Australia

Abstract

The postlarval (2mm) and juvenile (3-10mm) stages of three commercially important species of prawn (Metapenaeus bennettae, Penaeus plebejus and Penaeus esculentus) were sampled fortnightly for four months by beam trawl from five different habitats in Moreton Bay (27o12'S, 153o05'E). The habitats sampled represented two disturbed areas: a residential canal estate and a Zostera capricorni/Halophila ovalis seagrass bed adjacent to the canal estate revetment wall; and three undisturbed areas: a Z. capricorni seagrass bed located adjacent to a mangrove (Avicennia marina) area, a Z. capricorni/H. ovalis seagrass bed located adjacent to a mangrove (A. marina) area and a bare (mud) substratum. Postlarval and juvenile M. bennettae, P. plebejus and P. esculentus prawns were caught in highest densities on seagrass areas, with M. bennettae and P. plebejus densities highest on the two undisturbed seagrass areas. Although relatively low in density, P. esculentus was restricted to the three vegetated habitats, in particular the Z. capricorni seagrass bed and the Zostera capricorni/Halophila ovalis seagrass bed adjacent to the canal estate revetment wall. M. bennettae was the only species caught in any number from the canal, while P. plebejus was the only species caught in any number at the bare site. Laboratory studies were also conducted which indicated that seagrass was found to offer protection from predators for juvenile M. bennettae.