Main Article Content
Due to an observed increase in occurrence of alien species in Polish waters, research monitoring of the western region of the Baltic Sea has been conducted, in order to assess the spontaneous fish invasions. The outcome of that work was extraction of tub gurnard, Chelidonichthys lucernus (L., 1758), a fish belonging to ichthyologic rarities of the Baltic Sea. It prefers warmer and more saline waters of the Atlantic Ocean, the Mediterranean Sea and the North Sea. The specimens acquired were used for basic specific studies, describing the shape and size of the body.
Five measurable and twenty-seven countable traits were analyzed. As the result of this research the following formula, concerning the number of hard and soft fin rays, was composed: D1VIII; D2 15-16; A 15-16; V 7; P III, 15; C 19-20.
The results constitute input material necessary for further observations on tub gurnard’s ecology and biology. This research will add some new information to our modest knowledge about this species. It will become a significant source of information, especially if the gurnard as an alien species should have detrimental influence on the Baltic Sea’s biodiversity.
Key words: Chelidonichthys lucernus, tub gurnard, morphometry, invasive species, the Baltic Sea