Multicriteria GIS-based analysis for the evaluation of the vulnerability of the marine environment in the Gulf of Trieste (north-eastern Adriatic Sea) for sustainable blue economy and maritime spatial planning

The Gulf of Trieste, is a shallow semi-enclosed sea of about 500 km2 in the north-eastern part of the Adriatic Sea. The coastal and marine areas of the Italian region Friuli Venezia Giulia, which borders most of the Gulf of Trieste, are subject to significant pressure from human activities, especially in terms of maritime traffic, ports, industry, fishing and tourism. But they are also characterised by natural areas of high environmental value. We wanted to understand the human impact on these coastal and marine areas in order to better inform sustainable management.To carry out the analysis, we collected a range of anthropogenic (human) and environmental data, from which we produced a series of indicator maps. By combining the various indicators, we created two subsequent maps: the seabed vulnerability map and the marine environment vulnerability map in the area as a whole. The analysis has highlighted areas with different degrees of environmental vulnerability due to human development and identified the most critical areas in the Gulf of Trieste with high anthropogenic pressure. Both maps show that human impacts affect large areas of the seabed and marine environment, while those with minimal or non-existent impacts are very limited and are related mainly to areas with high levels of existing protection and conservation.The seabed vulnerability map shows that the biggest problems are related to discharge of dredging sludge, mollusc fishing with dredgers and turbo blowers, and anchoring boats. Furthermore, the presence of anthropogenic elements on the seabed can damage the natural environment and even permanently alter the natural shape and structure of the seabed. The marine environment vulnerability map shows that ports, urbanisation, industrial activities, maritime traffic and fishing pressure affect the entire study area.The vulnerability maps are a useful analytical tool to identify the most critical areas where possible actions can be planned to maintain a healthy and sustainable productive marine environment and to manage and resolve the conflicts between economic development and environmental health.