Seasonal and daily changes in the fish community and variations between commercial and non-commercial fish abundance were monitored in the inshore waters of the western part of the Gulf of Gdask (the Sopot territory). Samples were collected from December 1998 to December 1999, though monthly samplings, and supplemented by 24-hour investigations taken every three months, using a two-meter wide trawl. Among the 16 species collected, 5 were commercial and 11 were non-commercial. Juvenile forms of herring and flounder dominated the commercial fish; the highest catches were in March (89 ind. 100 m-2). Among the non-commercial fish, two species of Gobiidae (sand and common goby), and three-spine stickleback were most frequently caught. During the 24hour observations, commercial fish were noticed mostly at night. The investigated area is an important zone for both juvenile commercial fish and some ecologically important uncomercial species.