Danilo T. Dy, Frederick A. Uy, Christine M. Coralles
The rates of ingestion, egestion, ammonium excretion, and CO2 respiration of Tripneustes gratilla (Echinodermata: Echinoidea) from a shallow water embayment at eastern Mactan Island, central Philippines were examined. There was no significant diffcrence in weight-specific feeding rate with the three macrophytes (Sargassum polycystum, Thalassia hemprichii, and Kappaphycus alvarezii). The power function equation, M=KWb fitted well with the weight-specific egestion rates ((r2=0.93), weight-specific CO2 respiration rates (r2=0.92) and ammonium excretion rates (r2=0.86). Weight-specific egestion rates, CO2 respiration and ammonium excretion were indirectly proportional to body weight. For weight-specific egestion rate (in μg DW faeces/g DW urchin-h), the regression coefficient, b and constant, K were -2.31 ±0.68 (mean ±SE) (P=0.02) and 6359.55±5394.31 (P=0.29), respectively. The b and K for CO2 respiration were -1.28±0.48 (P=0.04) and 39.72±10.59 (P=0.01), respectively. For ammonium excretion, the b and K were -1.03±0.46 (P=0.11) and 262.51±56.89 (P=0.02), respectively.
Marine Biology Section, Department of Biology, University of San Carlos, Cebu City 6000, Philippines
