# Boating Tourism and Fishing Interactions: A Social Network Analysis Using AIS Data
## 3 Methodology
### Conceptual Approach  
It is ascertained whether there is any type of communication or cooperation between the social entities (i.e., the different vessels and the firms that operate them) with regard to the sharing of common resources (Figure 1). To this end, the terrestrial and satellite AIS records of the different vessels operating in the area under analysis are used to categorise the type of vessels according to the distance from the coast and the type of resources sought after.  
From the collection of these AIS data, it will be possible to explore ways of analysing them so that information can be obtained that may be useful for decision-makers to improve coastal management of maritime traffic in the areas under analysis [19; 20; 21; 27]. Thus, in the present study, it was defined that it would be possible to explore AIS data in three complementary ways, as described below. In short, namely, trying to understand the interaction between vessels of different activities (i.e., with the help of an SNA), understanding whether there are seasonal differences in terms of resource exploration and number of vessels (i.e., through Sankey diagrams), and summarising the hierarchy of the type of activities found in AIS pings according to resource exploration (i.e., through a dendrogram).  
Social network analysis (SNA): from the categorisation of these data, in order to better understand the complex interdependencies--similar to what has been conducted in other research contexts [10; 17; 45]--a social network was built, where the social network was composed of the categories/types of vessels, i.e., recreational and fishing, and the different activities that can be related. Social interaction (between these vessels) included the total number of AIS records and the pattern of proximity of other vessels.  
Sankey Diagram: To obtain another perspective of visualising the analysed SNA data, including the features, following the suggestions given by [PERSON] et al. (2016), a Sankey diagram was plotted. The Sankey diagram was constructed from the different proportions of the variables under analysis, i.e., anchoring port/marina, number of AIS pings relating to vessels according to their type (fishing or recreational), and the type of resource exploited. In this comparative analysis it is important to distinguish between the 3 months with a propensity for worse sea conditions and the other 3 months with more pleasant sea conditions, so the Sankey diagram was divided into two parts (the coldest period defined here for simplicity as January to March, corresponding approximately to winter, and the warmest period from July to September, adjusting to summer).  
Dendrogram: In addition to the above, in order to better understand the interaction of maritime vessel activities, a dendrogram--from the suggested approaches by [PERSON] (2017)--that uses a top-down hierarchical categorisation that incorporates the characteristics of all the vessels involved and groups them by clusters is defined. The similarities between the different activities are analysed. This type of analysis also gives clues about cooperative aspects or friction between different activities.