Effect of Nile tilapia, Oreochromis niloticus (L.), size on
phytoplankton filtration rate
H.
Turker, A.G. Eversole, D.E. Brune-2003
Aquaculture
Research, 34(12):
1087
Abstract:
Four
different-sized (390±3, 140±2, 40±2, 16±1 g) Nile tilapia, Oreochromis
niloticus (L.), stocked at the same biomass in timed pulse feeding
chambers were provided 27-29°C water dominated by Microcystis (82%)
and Scenedesmus (18%) to determine the effect of fish size on
filtration rates. The number of Microcystis and Scenedesmus
units filtered from the water decreased significantly with increasing
tilapia size. The shaping constants and maximum filtration rates for Ivlev's
feeding model used to describe the relation between filtration rates and the
suspended particulate organic carbon (POC) concentrations were significantly
different among the four sizes. Filtration rates of 763, 671, 512 and 300 mg
C kg-1 h-1,
which correspond to 70%, 82%, 86% and 90% saturation levels, were achieved
at POC levels of 30, 32, 32 and 33 mg C L-1
for 16, 40, 140 and 390 g Nile tilapia respectively. Smaller tilapia
achieved these rates at lower POC concentrations than larger tilapia.
(Department of Aquaculture, Fisheries and
Wildlife, Clemson University, Clemson, SC 29634-0362, USA. E-mail of A.G.
Eversole: aevrsl@clemson.edu)