Case study of the diet and parasite fauna of and extremely rare fish species Lumpenus lampraeteformis (Perciformes, Stichaeidae) from the Gulf of Gdañsk (south Baltic Proper)

Abstract The snakeblenny, Lumpenus lampretaeformis, is a post glacial relict from the last ice age in the Baltic Sea. Reliable data on its diet, parasite fauna, distribution, population size, and population trends in the Baltic Sea are lacking. In the Polish zone it has been observed only in ICES subdivisions 25 (Slupsk Furrow) and 26 (Puck Bay, Krynica Morska, Władysławowo and Vistula mouth fishing grounds) at depths of 30-70 m; however, in recent decades only one finding of snakeblenny in Polish waters has been reported. This paper reports the record of one female specimen from the Gulf of Gdañsk. The individual’s morphological characters, stomach contents, parasitic fauna, age and gonadosomatic index were examined. The parasitological examination, which was undertaken for the first time on a specimen from the Baltic Sea since the 1930s, revealed that L. lampretaeformis was the host of one parasite species, namely a juvenile acanthocephalan Echinorhynchus gadi. Additionally, Pontoporeia fermorata and Halicryptus spinulosus were recorded in the stomach of snakeblenny for the first time in the Baltic Sea.