Mariculture: Assessment of environmental variability as a tool for the sustainability of marine ecosystems and food security in Costa Rica.

The sustainability of ocean-based food systems is essential for coastal communities, especially those dependent on fisheries and mariculture, such as the Gulf of Nicoya in Costa Rica. Due to the depletion of fishery resources through overexploitation and climate change, mariculture, and in particular oyster farming, has emerged as a sustainable alternative that offers new economic opportunities for local communities. However, these systems face critical challenges, including pollution and degradation of the marine ecosystem, which affect both the quality of the product and the health of those who depend on this activity. Given the need to ensure the sustainability, equity and security of this food system, a project was developed with the main objective of strengthening mariculture in the Gulf of Nicoya through a study of environmental variation in oyster cluster and shrimp farming sites. The project analyses  water, sediments and oyster soft tissue by standardized methods to identify contaminants such as lead, cadmium, arsenic and mercury, as well as pathogenic microorganisms in both water (Enterococcus faecalis, fecal coliforms and Clostridium perfringens) and soft tissue of these organisms (Escherichia coli, Salmonella spp, Staphylococcus aureus, total aerobic counts, Vibrio parahaemolyticus and Listeria monocytogenes) without safety treatment; demonstrating the influence that anthropogenic activities from the mainland have on the marine ecosystem, for example heavy metals were found in sediment with the following ranges As: 45. 4 -49.9 µg/L; Cd: 0.317 - 1.40 µg/L; Pb: 9.68 - 60.7 µg/L, that may generate bioaccumulation at different trophic levels. At microbiological level, the maximum permitted ranges of the Central American technical regulation RTCA 67.04.50:08 for fresh marine products in mollusks were exceeded, constituting a food safety risk if not treated before consumption. This project provides scientific inputs that allow the communities of the Gulf of Nicoya to make informed and sustainable decisions in their mariculture practices, contributing to the quality of the final product and the protection of their environment. Thus, this effort strengthens food security by providing a system based on up-to-date environmental information that mitigates risks and promotes marine production in balance with the environment. The findings demonstrate the urgency, importance and vigilance of greater regulation in environmental management policies for land-based activities that affect the quality of marine life and, therefore, that of coastal communities, highlighting mariculture as a key activity for sustainable development. The proposal encourages a shift towards more responsible practices, adjusted to the effects of climate change, and offers an essential tool for the monitoring and adaptation of these productive activities.

Keywords: Food security, environmental monitoring, mariculture, sustainability