Observations on diet composition of Neogobius melanostomus Pallas 1811 (Gobiidae, Pisces) in the Gulf of Gdansk (Baltic Sea)

This study documents the diet of Neogobius melanostomus (round goby) from t hree different habitats within the Gulf of Gdansk. Diet composition of the round goby in the Gulf of Gdansk appears similar to that in its natural env ironment within the Ponto-Caspian Basin. In its native habitat, the round g oby feeds mainly on epibenthic organisms and opportunistically forages on s easonally abundant components of the benthic community. A natural mollusk-f eeder, the round goby feeds mainly on the mussel Mytilus trossulus in the G ulf of Gdansk. This food preference most likely, is due to the fact that M. trossulus is commonly distributed throughout most of the gulf and dominate s the benthic biomass. The adult round goby prefers an environment full of hiding places that also can be used for nests. Thus, submerged stones or co ncrete structures covered with colonies of M. trossulus are its preferred h abitat. Younger gobies are more abundant in the frontal areas of underwater concrete structures where the substrate is characterized by loose stones a nd the presence of Mya arenaria. These habitats have different faunal struc tures and, therefore, different trophic relations. The round goby, which is well suited for ecological expansion, has great potential to dominate the majority of the coastal zone of the Baltic Sea. Puck Lagoon, devoid of pred atory fish and rich in mussel beds, is an ideal habitat for this gobiid spe cies.