Benthic meiofauna response to mangrove oyster farming (Crassostrea gasar) in an Amazonian estuary

Abstract

Mariculture is expanding rapidly in northern Brazil, where oyster farming is a key economic activity. However, little is known about its effects on estuarine communities. This study assessed the influence of oyster farming (Crassostrea gasar) on the structure of the meiofauna community in the Curuçá Estuary (Pará, Amazon region). Sampling was conducted at two sites: an area beneath the oyster farming tables and a control area located 100 m away. Both areas had fine, well-sorted sediments, with higher organic matter content in the farming area. Twelve meiofauna groups were recorded, dominated by Nematoda and Oligochaeta. Density was lower in the cultivation area, while species richness did not differ between the sites. Gastropoda and Bivalvia were found beneath the cultivation tables, indicating enrichment. Multivariate analyses revealed differences in community structure associated with grain size and organic matter content. Overall, oyster cultivation induced moderate and limited changes, without exceeding ecological limits. The selective responses of meiofauna taxa highlight their potential as early indicators of aquaculture impacts in tropical estuaries and underscore the need for continuous environmental monitoring.