Filtration and clearance rates of Anadara grandis juveniles (Pelecypoda, arcidae) with different temperatures and suspended matter concentrations

Abstract

The mangrove cockle Anadara grandis (Broderip and Sowerby, 1829) is a potential candidate for aquaculture and for bioremediation of aquaculture effluents in the tropical and subtropical coastal areas of the eastern Pacific Ocean. Laboratory-produced spat are available, but there is no information on their responses to the range of environmental conditions to which they might be subject during the growth cycle. The aim of this study was to evaluate the filtration and clearance rates of A. grandis spat (shell length 9. 50±0. 37 mm) with a food concentration (7. 5 mg∙l-1) at four different temperatures (22, 25, 28 and 31 ºC, with pH=7. 5±0. 2 and O2concentration of 6. 4±0. 5 mg·l-1; experiment one); and with a temperature (25 °C) and five concentrations of suspended matter (from 7. 5 to 29 mg·l-1and pHand O2values of 7. 9±0. 2 and 6. 8± 0. 4 mg·l-1; experiment two). Filtration and clearance rates were highest at 25 ºC and significantly different (p. 05). In the second experiment filtration increased according to the amount of food available, but there were no significant differences (p>. 05) between 7. 5 and 11 mg·l-1and from 22. 4 to 29 mg·l-1. The trend was similar for clearance, and in this case significant differences were found (p