## 2 Materials and Methods
### Calculation of Traffic Density and Distance Cruise Ships Pass from the Island Shores  
The calculation of traffic density and the distance cruise ships pass from the island shores is based on traffic analysis during the busiest five-month period (August-October 2014 and June-July 2015). In order to identify density and determine the distance cruise ships traffic pass from the island shores and marine protected areas, regions of high navigational and environmental risk were selected. Regions of high navigational and environmental risk were selected based on the traffic monitoring results, geographical particularities, and environmental sensitivities of the selected area. Regions of high interest were Svetac, Bisevo and Susac and Lastovo islands, as well as the Bisevo-Vis passage, Vis channel, Hvar channel and the Susac-Lastovo and Lastovo-Mljet passages. On the chart, around the selected islands, 3 M diameter black circles are set. A distance of 3 M was set as a safe navigational reference and was in reference to International Convention for the Prevention of Pollution from Ships Annex IV (MARPOL), which stipulatesa 3 M limit for ships' sanitary water (grey water) discharge. The second reference was the 12 M territorial water limit marked with a light blue line. The distance of 12 M was also chosen in reference to International Convention for the Prevention of Pollution from Ships Annex IV (MARPOL), which stipulates a 12 M limit for ships' untreated wastewater (black water) discharge. Protected areas on the chart are marked with a green line (Figure 8a-c). Figure 8a-c are routing samples in the central and south Adriatic east coast, selected among all monitored cruise ship routes. Each of them represents the movement of one cruise ship in the researched period of time. Areas of interest are numbered and named, the blue lines show the cruise ship routes, the black circles indicate 3 M distance from the shore, dates and times indicate when a ship entered and left a 3 M or 12 M limit and the light blue lines show the Croatian territorial waters border (12 M limit). Analyzing Figure 8a-c and observing the times and dates of ships' arrivals and departures from 3 M or 12 M limits, it is evident that cruise routes are repetitive and have become navigational routine in the central and south part of the Adriatic east coast.Cruise ships' density in the researched areas was calculated following each cruise ship's route. In the process, the time of each ship's entrance and exit to 3 M and 12 M limits was recorded. Pre-set 3 M diameter circles and 12 M territorial waters limits were used as the main references in Figure 8a-c. Cruise ships that crossed the 3 M circle limit were considered to pass inside 3 M from the shore, cruise ship routes which passed close to the 3 M circle limit were considered to pass with a distance 3 M to 6 M from the shore, and open sea routes closer to the 12 M territorial water  
Figure 8: (**a**) Presentation of cruise traffic distance from the islands’ shores and display of >12 M retention calculation in the central and south Adriatic east coast; (**b**) presentation of cruise traffic distance from the islands’ shore and display of >3 M retention calculation with focus on the islands of Svetac and Bisevo; (**c**) presentation of cruise traffic distance from the islands’ shores and display of >3 M retention calculation with focus on the islands of Susac and Lastovo. border were considered to pass more than 6 M from the shore. Each cruise ship was counted and put into one of three categories according to the distance they passed from the islands shore: (1) <3 M from shore, (2) 3 M to 6 M from shore and (3) >6 M from shore. Cruise ships retention period inside 3 M from shore is also calculated. The time difference between the entrance and exit from the 3 M diameter was taken into consideration, and it was calculated and expressed in minutes. The collected data related to the distance cruise ships pass from the islands' shores and traffic density are grouped in four tables (Tables A1-A4).