Effects of Temperature and Body Size on the Clearance Rates of a Tidal Flat Bivalve, Coecella chinensis (Deshayes)

Abstract

To know the effects on temperature and body size on the clearance rate (CR) of a small tidal flat bivalve, Coecella chinensis, laboratory experiments were performed with 20 individuals of different sizes (ranging from 7 to 25 mm) at 3 different temperatures (10, 15, 20℃). The relationship between body size and CR was determined by an allometric equation. The CR of C. chinensis varied greatly ranging from 0.003 to 0.103 L/individual/hr. Both temperature and body size affected significantly on the CR of C. chinensis. The CR at 20℃was 1.5 times higher than that at 15℃ and 2.8 times than 10℃. The temperature coefficient (Q10) between 10 and 15℃ was higher than that between 15 and 20℃, which indicates that C. chinensis changes its CR more rapidly in lower temperature range. As body size increased, the CR increased more than 10-fold at all temperatures. The CR relative to flesh dry weight (FDW) were fitted well to the power function: CR = a × (FDW)b . The exponent value (b) of the fitted equation ranged from 0.64 to 0.70, which are similar to those of other bivalves. The weight-specific CR (CRw) was still affected by body size (p < 0.05). This implies that smaller individuals require more energy per unit biomass for growth, and the energy requirement for growth decreases as body size increases.