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Meager, J.J.; Williamson, I.; Loneragan, N.R. and Vance, D.J. (2005). Habitat selection of juvenile banana prawns, Penaeus merguiensis (de Man): testing the roles of habitat structure, predators, light phase and prawn size Penaeus merguiensis. Journal of Experimental Marine Biology and Ecology 324 (2): 89-98. The effects of fish predators, light phase, habitat structure and prawn size on the habitat preferences of juvenile Penaeus (Fenneropenaeus) merguiensis de Man were examined with laboratory experiments. The behaviour of juvenile P. merguiensis within habitats of different structural complexity was also examined. Experiments were carried out in a tank (1.8 m diameter) divided into four habitats representing: bare substratum, leaf litter (little vertical structure), mangrove pneumatophores (regular vertical structure) and mangrove woody debris (heterogeneous vertical structure). The location of 10 prawns was monitored over 270 minutes (135 minutes light and 135 minutes dark), with different prawns five times for each combination of prawn size class, and predator (no predator; Arius graeffei Kner and Steindachner and Lates calcarifer Bloch). In the absence of predators and during the light phase, when observations
on prawn behaviour were made, swimming was the most common behaviour (of
seven mutually exclusive behavioural categories) with few differences
in behaviour between sizes. All size classes of juvenile P. merguiensis selected vertical structure (mangrove debris and pneumatophores) over
low vertical structure (leaf litter and bare substratum) in both light
and dark conditions, and in the presence or absence of predators. When
L. calcarifer was present, the selection by prawns of the mangrove-debris
habitat increased significantly. This was attributed to an increase in
predation risk in the other habitats. L. calcarifer rarely pursued prey
amongst the mangrove debris structure, compared to habitats with less
heterogeneous vertical structure (pneumatophores, leaf litter and bare
substratum).
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