Coralligenous habitat represents one of the most important biodiversity hotspots in the Mediterranean Sea. Structured by calcareous encrusting algae and hosting a wide array of sessile and mobile marine species, it provides key ecosystem services such as coastal protection, carbon sequestration, and nursery areas. However, increasing anthropogenic pressures, particularly from fishing activities, pose serious threats to its integrity.

This study aimed to assess the loss of natural capital associated with the degradation of coralligenous habitat due to fishing activities in the Tremiti Islands Marine Protected Area (MPA), Southern Italy. A multidisciplinary approach was adopted, integrating sampling activities, field observations, environmental accounting and spatial analysis.

The biophysical and economic value of the natural capital stock was first estimated using an environmental accounting model. To assess fishing impacts, structured questionnaires were administered to divers and tourists, identifying areas where lost or abandoned fishing gear is frequently observed. Underwater surveys and image analysis were then conducted to quantify physical damage to benthic communities. Spatial data were integrated into GIS to generate thematic maps of fishing pressure and habitat vulnerability.

The results revealed a 15% loss of coralligenous natural capital, corresponding to an economic disvalue of approximately €840,000. This degradation was primarily due to the presence of entangled nets, fishing lines, and other abandoned gears causing structural damage to the habitat.

The study provides a replicable method to evaluate the impacts of fishing on vulnerable habitats in the Mediterranean Sea. Its outputs are relevant for informing conservation priorities, supporting the sustainable management of MPAs. Promoting such interdisciplinary assessments is essential to safeguard biodiversity while ensuring the generation of ecosystem services in response to growing anthropogenic threats