Data on the presence and distribution of alien species recorded by expert observers in the framework of the project "Presence and health aspects of alien fish species in the western Ionian Sea, eastern Sicily" (year 2019) carried out by the MareCamp association as thesis coordinator for students of the University of Messina. The project included surveys from Catania to Siracusa waters during fishing trips using different fishing gears (trammel, trowler, single net), observation, measurement, necroscopy, microscope analisys, and interviews with fishermen.

Data on stranded cetaceans and sea turtles along the Sicilian coast and waters, in the framework of the project "Dolphin watching and conservation in the gulf of Catania" and the "Report a sighting and help the research" initiative promoted by the MareCamp association.

Data on the presence and distribution of marine species during underwater visual census activities in the Gulf of Catania, Eastern Sicily, Ionian Sea. Data were collected on fixed line transects placed from 5 to 12 meters of deep, using scuba diving ARA equipment, and they include: date, time and geographical coordinates of the surveys, recorded species, size and number of individuals. The monitoring was supervised in years 2015 and 2016 by the MareCamp association.

Data collection on population size and distribution of cetaceans in Sicily, Ionian Sea, promoted by the MareCamp association thanks to the citizen science initiative "Report a sighting and help the research" through phone and e-mail communications made by yachtsmen and fishers, and also filling in the following online form https://forms.gle/mAx9ZHZDzrPfs9P59 Data here provided were collected in 2008-2019 period. The project is ongoing; sightings are reported in the database only if the advisories have good photos of reference able to distinguish the species and the area of observation. Presence of boats, fishing activities, other species like birds, fish, jellyfish, meteorological and sea conditions are also collected.

Data on population size, structure, behavior and distribution of cetaceans and sea turtles in eastern Sicily, Ionian Sea, collected by expert observers of the MareCamp association in the framework of the project "Dolphin watching and conservation in the Gulf of Catania" (years 2015-2019).

Data on different mobile species recorded by expert observers in Sicily, Ionian Sea, with a focus in the Gulf of Catania, in the framework of the project "Dolphin watching and conservation in the Gulf of Catania" promoted by the MareCamp association (years 2015-2019), and the "Floating Laboratories" initiative carried out with the supervision of the Low Impact Fishers of Europe (LIFE) platform (year 2019).