Validating a proxy to carrying capacity for finfish offshore aquaculture in the western Mediterranean

Abstract

After developing a proxy for carrying capacity (CC) for marine finfish aquaculture integrating physical, ecological, social, and economic factors (Romero et al.,2023), this study presents an in situ validation of the proxy. To achieve this, we applied the harmonized Environmental Monitoring Program (EMP) developed by Aguado-Giménez et al. (2012) for finfish aquaculture farms in the Mediterranean Sea. We hypothesised that if the proxy indicated CC had been exceeded, some variables would surpass acceptable thresholds. Our findings confirmed that two of the three facilities exceeded thresholds for one or more indicator variables. However, this study focused on environmental CC, lacking defined thresholds for socio-economic indicators. This gap underscores the necessity for developing social and economic indicators to identify exceeded CC in these dimensions. Including these ensures success, reflecting that aquaculture operates within a socio-ecological system and promoting a holistic, participatory process involving stakeholders. Our study emphasizes integrating CC proxies into regulatory frameworks for aquaculture spatial planning and management. This, combined with the GIS-based application of CC calculations to AZAs identified in the Spanish Mediterranean (Fourdain et al., this issue), demonstrates these tools' applicability. For the first time, a CC proxy has been incorporated into a holistic and innovative framework balancing ecological, social, and economic considerations. Its simplicity and effectiveness make it a valuable tool for integrating into marine spatial planning and redefining AZAs with CC in mind. However, broader application necessitates adapting these proxies to various aquaculture systems. The socio-ecological heterogeneity across regions requires tailoring models to local conditions to harmonize spatial planning with environmental and socio-economic objectives effectively.