The Miramare Reserve, in the Gulf of Trieste (North Adriatic‐Italy), is a small marine protected area (121 hectares) for research, education and conservation and is managed by WWF Italy. Different techniques for taking a qualitative and quantitative census of the fish species, for mapping the nests ofGobius cruentatus, Tripterygion delaisiandCbromis chromis, for studying the reproductive behaviour ofC. cbromisand for measuring the sea ambient noise were used. Visual census techniques were applied in the comparison of two areas which were similar from a morphological point of view, but differed in human activity.