Dynamics of Colonization of Artificial Supports by Mangrove Oysters at Touguissouri (Republic of Guinea)

Oysters from mangroves constitute an important food and economic resource for the coastal populations of Guinea. Unfortunately, traditional harvesting on mangrove roots is threatening these ecosystems, and climate change is exacerbating the risk of decline. This study analyses the colonisation of oysters on artificial supports in the Touguissouri estuary, by assessing interactions with barnacles, competing organisms, and the influence of physico-chemical parameters. Collectors were immersed at various depths. Environmental parameters such as salinity, pH, turbidity, etc. were measured, and the settlement of oysters and barnacles was monitored. The data collected was analysed and statistical tests were used to identify the factors influencing colonisation. High seasonal variability was observed, with high salinity in the dry season and increased turbidity in the wet season. pH and nutrients influence biological productivity. Larval settlement is optimal at a depth of 30 cm, where conditions are favourable. Recruitment peaks occur in the rainy season (July-October), correlated with high turbidity and a basic pH. Intermittent competitive exclusion is observed with barnacles and influenced by salinity and substrate availability. Artificial supports, particularly rough ones, improve the settlement of oysters, reducing pressure on mangroves. These results underline the importance of adapting substrates to local conditions for sustainable oyster farming. This study demonstrates the potential of artificial supports for oyster culture in Guinea, while identifying ecological constraints (competition, seasonal variability).