Parasites of a saithe, <I>Pollachius virens</I> (L.) captured in the Baltic Sea

resenting the family Gadidae. It naturally occurs in the North Atlantic Ocean and it has been rarely reported from the Baltic Sea (Froese and Pauly 2008). The hitherto conducted parasitic surveys of this fish focused on the Atlantic, particularly the Sea of Norway and the Barents Sea (e.g., Rokicki and Strömberg 1991, Karasev et al. 1996, Strømnes and Andersen 1998, Lom 2002). The Baltic Sea is a brackish inland body of water with salinities ranging from 3.7 PSU (Bothnian Bay) to 8 PSU (Pomeranian Bay) (Łomniewski et al. 1975). Its animaland plant species diversity is much lower than that of fullsalinity seas. It is particularly evident in the composition of its fish fauna and invertebrate fauna. The low species diversity of potential definitive, intermediate, or paratenic hosts may also theoretically affect the species richness of fish parasites (Rhode 2002, Zander and Reimer 2002). Therefore it would be interesting to compare the parasite faunas of saithe from the Baltic Sea and Atlantic Ocean. The results of the presently reported study comprise the first published parasite records of saithe from the Baltic Sea off Polish coast. In March 2007, a single, semi-ripe female saithe, Pollachius virens (99 cm TL, 9.2 kg), was caught in the Gulf of Gdańsk. The fish was promptly subjected to a standard parasitological necropsy. The microsporidians found were smeared on a microscopic slide and mounted in glycerolgelatine. The nematodes and acanthocephalans were fixed in a mixture of acetic acid and formalin. Selected nematodes were cleared in lactophenol and mounted in glycerolgelatine. The acanthocephalans were stained in Gowers carmine, dehydrated in glacial acetic acid, and cleared in benzyl alcohol. The following parasites were recovered from the fish examined MICROSPORA Glugea sp.: 3 spherical cysts, infecting intestine, 0.8 mm in diameter; spore 5.7–5.9 μm (5.7 μm) × 1.5–2.1 μm (1.8 μm). NEMATODA Anisakis simplex (Rudolphi, 1809) L3: 474 specimens, including 1 nematode on the spleen, 17 on the intestine, 32 on the stomach (including 3 penetrating the stomach wall), 65 on the pyloric caecae, and 359 on the liver (134 on the one lobe and 225 on the other). Contracaecum osculatum (Rudolphi, 1802): L3: 1 specimen on the liver. Hysterothylacium aduncumaduncum (Rudolphi, 1802): 1 adult female (with eggs visible in her uterus) in the intestine (Fig. 1, Table 1) Hysterothylacium aduncum gadi (Müller, 1776): 3 specimens in the intestine (2 females, including a mature one; 1 male) (Fig. 2, Table 1). ACANTHOCEPHALA Echinorhynchus gadi Müller, 1776: 3 specimens in the intestine (2 females, 1 male). The presently reported study constitutes the first report on saithe parasites from the Baltic Sea. However, the helmints found have already been recorded from this fos outside the Baltic Sea. In addition, the genus Glugea was represented by Glugea punctifera Thélohan, 1895, infecting the connective tissue of the ACTA ICHTHYOLOGICA ET PISCATORIA (2008) 38 (2): 143–147 DOI: 10.3750/AIP2008.38.2.10