Ra. Kenyon et al., HABITAT TYPE AND LIGHT AFFECT SHELTERING BEHAVIOR OF JUVENILE TIGER PRAWNS (PENAEUS-ESCULENTUS HASWELL) AND SUCCESS RATES OF THEIR FISH PREDATORS, Journal of experimental marine biology and ecology, 192(1), 1995, pp. 87-105
The burying and sheltering behaviour of two different sizes of juvenil
e tiger prawns (shrimp) Penaeus esculentus Haswell was studied during
light and dark periods, in three habitats: bare silt substratum; short
, thin-leaved seagrass (Halodule uninervis Aschers.); and tall, broad-
leaved seagrass (Cymodocea serrulata Ashers & Magnus). Relative predat
ion rates by the sand bass Psammoperca waigiensis Cuvier were also stu
died in these three habitats and in an additional seagrass with tall,
thin leaves (Syringodium isoetifolium Ashers), Burying behaviour diffe
red with prawn size, seagrass habitat and exposure to light. Small pra
wns (2.5 to 3.5 mm carapace length [CL]) rarely buried, even on bare s
ubstratum, whereas large prawns (11 to 13 mm CL) buried often and in a
ll habitat types. However, large prawns buried in the substratum less
often in tall, broad-leaved seagrass than in short, thin-leaved seagra
ss. Small prawns remained emerged in both the light and dark, whereas
large prawns spent more time above the substratum in the dark than in
the light. Small prawns perched on all types of seagrass leaves, where
as large prawns perched only on the broad-leaved seagrass. Fish detect
ed juvenile P. esculentus (4 to 5 mm CL) more quickly in narrow-leaved
seagrasses than in broad-leaved seagrass, and more quickly and more o
ften, on bare substratum than in narrow-leaved seagrasses. More juveni
le prawns were detected in bare substratum and the thin-leaved seagras
ses, S. isoetifolium and H. uninervis, than in the broader-leaved C. s
errulata. More prawns were caught and eaten on bare substratum than in
the broad-leaved seagrass. These results indicated that small juvenil
e tiger prawns would suffer higher rates of predation in short, thin s
eagrass and unvegetated habitats, and this would lead to a decrease in
abundance in these habitats. In the field, observations of the abunda
nce of prawns in seagrass habitats of different structural complexity
suggests post-settlement processes such as predation may explain prawn
distribution.