Removal of seston by crassostrea rhizophorae (guilding, 1828) in the vitoria bay estuarine system, brazil

ABSTRACT The clearance of organic suspended particles by bivalve mollusks in estuarine ecosystems has been considered a key regulating service. In Neotropical estuaries and associated mangrove ecosystems, the mangrove oyster, Crassostrea rhizophorae, is a key species in such process. To evaluate C. rhizophorae clearance rates (CRbd), biodeposit experiments were carried out at dry (2015) and wet (2016) seasons, in three sites of the Vitoria Bay Estuarine System (VBES), southeastern Brazil. The average CRbd was 0.67 L.g−1.h−1, which can be regarded as low CR. Although organic fraction predominate in the particulate matter (>60%), estuarine high salinity caused by low river discharge during prolonged regional drought, impaired oyster feeder rates. When the CRbd take in account the estimate entire mangrove oyster biomass at the VBES (3.77 × 105 kg.km−2) it yields a rate of 6.51 × 106 m3.kg−1.day−1, corresponding to a mean daily capacity of organic seston removal of 26% of the total estuarine volume. Even conservative, this result highlight the importance of mangrove oyster for the estuarine regulation, emphasizing its ecological importance and the needs to sustain the key ecosystem services of regulating estuarine environmental quality.