Duck body condition affects the number of parasites in the gastrointestinal tract, as evaluated with the Akaike information criterion.

The aim of the study was to determine the relationship between the body condition, and the number of parasites in the gastrointestinal tract of the tufted duck (Aythya fuligula), using the Akaike information criterion. Absolute and relative measurements of 197 ducks were taken. Liver mass was positively associated with the number of parasites in the duodenum (ß = 0.5). Heart mass affected positively the number of parasites in the rectum (ß = 2.3), the number of nematodes in the jejunum (ß = 7.45), the total number of trematodes (ß = 1.7), their number in the ceca (ß = 7.3) and rectum (ß = 4.2), and the number of cestodes in the ceca (ß = 8.2). Beak length influenced the number of nematodes in the rectum (ß = 1.7). Left tarsometatarsus length (ß = 1.4) and relative head height (ß = -2.0) affected the number of trematodes in the ceca. Tail length influenced negatively the number of cestodes in the ileum (ß = -0.2). Similarly, a ratio of body mass to body length was negatively associated with the total number of parasites (ß = -0.1), their number in the ceca (ß = -0.2) and rectum (ß = -0.3), the total number of trematodes (ß = -0.3), and their number in the ceca (ß = -0.5) and rectum (ß = -0.4). A ratio of keel-skin length to keel length affected differently the total number of parasites in the ceca (ß = 9.1), the number of nematodes in the jejunum (ß = -17.9) and the number of trematodes in the duodenum (ß = -5.8). A ratio of fat mass to body length affected the number of cestodes in the jejunum (ß = 1.8). The present study indicates some morphological and anatomical parameters that may be useful for determining the correlation between the body condition and the level of parasitic infection.

Redescription of Quasiamidostomum Fulicae (Rudolphi, 1819) Lomakin, 1991 (Nematoda: Amidostomatidae), a Parasite of Fulica Atra (Gruiformes).

INTRODUCTION: Quasiamidostomum fulicae (Rudolphi, 1819) Lomakin, 1991, is a species of which the systematic position is still unclear, and it is reported in the literature under many synonyms. In the present study, an attempt has been made at establishing the ultimate systematic position of Quasiamidostomum fulicae against the backdrop of selected Amidostomatinae species. MATERIAL AND METHODS: The parasites were identified based on measurements of external and internal structures. Ecological analysis of Q. fulicae was carried out using the quantitative indices (frequency, prevalence, mean intensity, relative abundance, and dominance index). Statistical analyses (discriminant analysis) were performed on measurement data. RESULTS: The intestines of 77 coots were examined. They yielded a total of 398 parasites, including 67 identified as Q. fulicae. Both males and females were located in the muscular gizzard. The morphometric analysis of Q. fulicae in this study showed the dimensions of all the internal organs to be in agreement with measurements reported by other authors. The discriminant analysis, used to find the differences between the examined nematode species (Amidostomoides acutum, A. petrovi, A. monodon, Amidostomum anseris, and Quasiamidostomum fulicae), gave highly significant results (P < 0.0001) with respect to both males and females. CONCLUSION: The results justify the separation of Q. fulicae from the genus Amidostomum.

Morphological and ecological characteristic of Dicranotaenia stenosacculata Macko, 1988 (Cestoda, Hymenolepididae) recorded in Poland

During the parasitological examination of 288 wild ducks from north-western Poland, 18 tapeworms were found in the intestines (jejunum, ileum and rectum) of six birds, which, based on the structure of the scolex, internal organs and the presence of cirrus with an internal additional sac, were determinated as Dicranotaenia stenosacculata Macko, 1988. Tapeworms were found in two young females Bucephala clangula, one young female Aythya marila as well as two adult males Aythya fuligula. The aim of the study was to present the morphological and ecological characteristics of the species, recently discovered for the first time in the fauna of Poland.

Taxonomic structure of cestodofauna of two species of diving ducks Aythya fuligula and A. marila (Anseriformes: Aythyini) in north-western Poland

Diving ducks Aythyini Delacour et Mayr, 1945 are an interesting object of the parasitological studies because due to living in two environments (aquatic and terrestrial) and migrating over long distances, they can come into contact with many potential hosts for parasites. In the recent years, a decrease in the population of diving ducks has been observed, especially of the tufted duck and the scaup. Both of them remain the most common species found in the region of West Pomerania, so the presented research is limited to the parasitological studies of these two species of ducks. The aim of this study was to determine the taxonomic structure of the cestodofauna of two species of diving ducks, the tufted duck and the scaup, wintering in north-west Poland. The research material consisted of 14,734 tapeworms collected from digestive tracts of 256 birds, 174 tufted ducks Aythya fuligula (Linnaeus, 1758) and 82 scaups A. marila (Linnaeus, 1761). All identified tapeworms obtained from digestive tracts of the hosts belonged to the Hymenolepididae family (order Cyclophyllidea). A total of 25 species of 9 genera were identified in the cestodofauna of the tufted duck, while in the cestodofauna of the scaup: 12 species of 7 genera. During 10 years of studies out of all of the 26 recorded species, 6 have been found in Poland for the first time. Moreover, 13 new, unlisted parasite-host relationships have been identified: 7 in the digestive tract of the tufted duck and 6 in the scaup.

Tetrameres globosa (Linstow, 1879) (Nematoda, Tetrameridae) ­ a nematode of the Eurasian coot Fulica atra (Linnaeus, 1758) recorded for the first time in Poland

During parasitological studies of 23 Eurasian coot Fulica atra (Linnaeus, 1758), 91 nematodes were isolated. Three of them, found in the proventriculus, were identified as Tetrameres globosa (Linstow, 1879). This paper presents the morphological characteristics of the discovered males of T. globosa.

The use of selected statistical methods and Kohonen networks in the revision and redescription of parasites

Revisions and redescriptions of species and higher taxa have been known in parasitology since the first description of a parasite. Usually, they are based on standard morphometric methods or more modern genetic analysis. The former are not always sufficiently reliable, while the latter often require expensive equipment, pre-defined genetic markers, and appropriately prepared research material. They may be replaced by multivariate statistical methods, in particular discriminant analysis and cluster analysis, and Kohonen artificial neural networks included in data mining. This paper presents the examples of specific applications of these methods for the verification of the affinity of nematodes. The discriminant analysis showed that it was possible to statistically significantly discriminate individual nematode species, both for males and females, based on morphometric variables. This confirmed the previously assumed division of the species complex Amidostomum acutum into three distinct species. Similarly, hierarchical cluster analysis, used for the determination of coherent groups of nematode parasites, allowed the identification of relatively homogeneous clusters of nematode species depending on their circle of hosts, and groups of hosts.

Revision of the species complex Amidostomum acutum (Lundahl, 1848) (Nematoda: Amidostomatidae) by use of molecular techniques.

The aim of the work is to confirm the species differentiation of the nematodes of the Amidostomatidae family: Amidostomoides acutum (Lundahl, 1848) Lomakin, 1991; Amidostomoides monodon (Linstow, 1882) Lomakin, 1991, and Amidostomoides petrovi (Shakhtahtinskaya, 1956) Lomakin, 1991, which still are used in the parasitological literature as synonyms of Amidostomum acutum (Lundahl, 1848). The research material consisted of nematodes isolated from gizzards of dabbling ducks from the north-west of Poland. To confirm the species differentiation, DNA from the nematodes was isolated and approximately 630bp of the 28S rRNA gene were sequenced. The obtained DNA sequences were tabulated and then phylogenetic analysis were conducted using the UPGMA method. The results of the research distinctly diversify the nematodes of the genus Amidostomoides at the DNA level, which together with morphological and ecological differences among them (hosts from different systematic groups) enables to classify them into the separate species.

Mercury and selenium in the muscle of piscivorous common mergansers (Mergus merganser) from a selenium-deficient European country.

Although the relationship between mercury (Hg) and selenium (Se) has been studied in wild birds in areas with sufficient or excessive Se levels, little is known about this relationship in areas where the supply of Se is limited. As Hg detoxification is based on the production of biologically inactive Hg-Se complexes, the aim of this study was to investigate the relationships between the concentrations of total mercury (THg), methylmercury (MeHg), inorganic mercury (InHg=THg-MeHg), percent MeHg of THg, Se and molar ratios (THg:Se, MeHg:Se, InHg:Se) in the breast muscle (n=16) of the piscivorous common mergansers (Mergus merganser) from a Se-deficient and moderately Hg-polluted area in Poland. Mergansers were divided into two groups differing in condition (A-very good condition; C-moderate condition). Concentrations of THg, MeHg and Se were determined by atomic absorption spectrometry, modified gas chromatography atomic fluorescence spectroscopy, and spectrofluorometric methods, respectively. In all studied mergansers, mean concentrations of THg, MeHg, InHg, and Se in muscle were 2.63, 1.92, 0.46, and 0.54µgg(-1)dw, respectively. THg and MeHg concentrations in the muscle of group A mergansers were greater than in group C. The ratio of THg:Se was higher in group A than in group C (2.32 vs 1.36; p<0.01), as well as the molar ratio of MeHg:Se (A vs C: 1.98 vs 1.03; p<0.05). Comparisons between mergansers from Poland and Canada showed similar THg and percent MeHg in the muscle, but mergansers from Poland had several times lower Se levels and higher THg:Se ratios (>2.0) than the Canadian mergansers and other European and North American waterbirds. We found statistically significant positive correlations (MeHg-THg, percent MeHg/THg-MeHg, percent InHg/THg-InHg, THg:Se-THg, MeHg:Se-THg, THg:Se-MeHg, MeHg:Se-MeHg, InHg:Se-InHg, MeHg:Se-THg:Se) and some negative correlations (percent InHg/THg-MeHg, percent MeHg/THg-InHg, THg:Se-Se, MeHg:Se-Se). As THg and percent MeHg in the studied mergansers were similar to populations living in non-Se-deficient areas, it is likely that different mechanisms of muscle Hg detoxification have evolved in mergansers populations living in Se-deficient areas.

Hepatic and nephric mercury and selenium concentrations in common mergansers, Mergus merganser, from Baltic Region, Europe.

The subject of the present study was the piscivorous common mergansers (Mergus merganser). The total mercury (THg), methylmercury (MeHg), selenium (Se) inorganic mercury (InHg; THg - MeHg), percentage of THg that is MeHg (%MeHg), molar ratios (THg:Se, MeHg:Se, InHg:Se), and their mutual relations in livers and kidneys were determined in ducks from an Se-deficient area in Poland. The authors verified a hypothesis that, as a result of living in an Se-deficient region, mergansers from Poland should have higher THg:Se ratios than other waterbirds with similar THg tissue levels. Although a comparison of healthy mergansers from Poland and Canada showed similar THg tissue contents, the group in the present study had a few times lower Se levels and higher THg:Se ratios (overall means >1.7 in both livers and kidneys in all studied individuals) than the Canadian group and other European and North American waterbirds. The authors found significant correlations between various relations, including MeHg-THg, InHg-THg, Se-THg, %MeHg-THg, InHg/%THg-THg, %MeHg/THg-InHg, %InHg/THg-InHg, MeHg:Se-THg:Se, InHg:Se-THg:Se, InHg:Se-MeHg:Se in liver and InHg-THg, Se-THg, Se-InHg, %MeHg-THg, %MeHg-InHg, %InHg/THg-InHg, THg:Se-THg, InHg:Se-THg, MeHg:Se-MeHg, THg:Se-InHg, InHg:Se-InHg, and InHg:Se-THg:Se in kidney. It is likely that the main factor responsible for the high value of THG:Se ratio (>1) in mergansers from Poland is Se deficiency in central and northern Europe. Therefore, this element is unlikely to participate in the detoxification of Hg in these birds.

Morphometrical and ecological analysis of nematodes of the family Capillariidae (Neveu-Lemaire, 1936) in wild ducks (Anatinae) from the north-western Poland.

West Pomerania is located on the migratory route of many species of birds. Among them are many representatives of wild duck species (subfamily Anatinae), which are often the primary hosts of many helminths due to the fact of living in two different environments: terrestrial and aquatic. However, until the end of the 90s, research conducted in Poland on the helminth fauna of wild birds, including nematodes of the family Capillariidae, did not include the north-western region of the country. These first studies performed in 1999, aimed at the identification of the nematodes of wild ducks from the West Pomerania region, revealed the presence of three species belonging to family Capillariidae, i.e. Capillaria anatis (Schrank, 1790) Travassos, 1915, Eucoleus contortus (Creplin, 1839) Gagarin, 1951 and Pseudocapillaria mergi (Madsen, 1945). The purpose of the current study was to perform a comprehensive ecological analysis of C. anatis, E. contortus and P. mergi, including such factors as intensity, prevalence, relative density, index of fidelity and dominance index. The experimental material comprised 811 nematodes isolated from the gastrointestinal tracts of 953 ducks. These 9 species of ducks belong to three different tribes of the Anatinae subfamily: Anatini (Anas clypeata, A. crecca, A. platyrhynchos), Aythyini (Aythya fuligula, A. marila) and Mergini (Bucephala clangula, Clangula hyemalis, Mergus merganseri, Somateria mollissima) and diverse in terms of their biology and ecology. The morphometric and morphological analyses fail to identify any significant differences in the body structures of nematodes of the species C. anatis, E. contortus and P. mergi of the West Pomerania region in comparison with those found in other regions of Poland and Europe. The ecological analysis of the Capillariidae family in the West Pomerania region revealed that ducks of the tribe Anatini (mainly A. platyrhynchos) are the most common hosts of E. contortus species, C. anatis is most commonly found in ducks of the tribe Aythyini, and P. mergi is relatively frequent in ducks of the tribe Mergini (mainly in M. merganser).

Morphological features of Cloacotaenia megalops (Nitzsch in Creplin, 1829) (Cestoda, Hymenolepididae) from different hosts.

The tapeworm species Cloacotaenia megalops (Nitzsch in Creplin, 1829) is characterized by a very specific morphology. A particularly distinct feature is a large almost square scolex in which four fleshy suction cups are embedded and a rudimentary rostellum. During standard studies of wild duck cestode fauna in northwestern Poland, some morphological differences were observed among specimens, mainly in the shape of scolices and hermaphroditic proglottids of C. megalops isolated from different bird species. This paper attempts to demonstrate the impact of the host species on morphology of the parasite. The study material consisted of 39 individuals of C. megalops (19 from Aythya fuligula, 10 from Anas platyrhynchos, 4 from Bucephala clangula, 4 from Aythya marila and 2 from A. ferina). The isolated parasites were fixed and stored in 70% ethanol and solid preparations were made. Selected external and internal structures of the parasite were measured and photographed using a Zeiss microscope, a microscope camera Opta Tech 2.1 and Opta View 6.0.2.2. It was stated that the sizes of the most important elements of the parasite morphology are generally consistent with those presented in the available literature, nevertheless some differences were observed in both morphology and sizes of some anatomical structures, especially in the form of scolices and hermaphroditic proglottids between specimens isolated from hosts representing three different eco-tribes (Aythyini, Anatini and Mergini).

Cloacotaenia megalops (Nitzsch in Creplin, 1829) (Cestoda, Hymenolepididae) in wild ducks in Western Pomerania, Poland.

Cloacotaenia megalops (Nitzsch in Creplin, 1892) is a polyxenic and cosmopolitan tapeworm from the family Hymenolepididae. Its generic name derives from their typical location (cloaca), and the typical final hosts which are birds typically associated with water and marsh environments: Anseriformes, Galliformes and Gruiformes. In Poland, the presence of C. megalops has been observed so far in 16 species of ducks from the Baltic coast, the Mazurian Lake District, Wielkopolsko-Kujawska Lowland, Mazovian Lowland, and Podlasie Lowland. In Western Pomerania, quantitative structure analyses were only carried out on Anas platyrhynchos, and therefore the aim of this study was the detailed analysis of environmental populations of C. megalops in wild ducks. The examined tapeworms were isolated from the digestive tract of 1005 wild ducks representing 17 species belonging to three different eco-tribes: Anatini (n=225), Aythyini (n=413) and Mergini (n=367), from northwestern Poland. During the Study 187 C. megalops were found in 89 birds (8.8% of examined ducks) belonging to 7 species: Anas crecca (common teal), A. querquedula (garganey), A. platyrhynchos (mallard) (Anatini); Aythyaferina (pochard), A. fuligula (tufted duck), A. marila (greater scaup) (Aythyini) and Bucephala clangula (goldeneye) (Mergini). The results show the differences in the quantitative structure of C. megalops among the examined species of ducks. The highest prevalence was found in mallard (18.6%) and the lowest in greater scaup (3.2%). The highest mean intensity was observed in greater scaup (4.0), and the lowest in garganey and common teal (1.0). Relative density was at a similar level in the tested birds. Based on the ratio of dominance, it was found that C. megalops is a rare species in the cestodofauna in the examined birds.

Revision of the species complex Amidostomum acutum (Lundahl, 1848) (Nematoda: Amidostomatidae).

Most available literature indicates that the most dominant nematode in Anatinae is a cosmopolitan species Amidostomum acutum (Lundahl, 1848). However, studies on wild duck helminthofauna in northwestern Poland suggest that these birds are attacked by not one but three different parasite species, previously described as a single species. Hence the aim of this study was the redescription of the species complex Amidostomum acutum, conducted on a representative sample of parasites and their hosts. The study material consisted of 6,430 nematode individuals, isolated from the digestive tracts of 1,005 wild ducks, representing 17 species. Unsupervised classification was performed using a Kohonen artificial neural network. The analysis confirmed the division of nematodes into three groups corresponding to three species, both for males and females. Taking into account the qualitative characteristics of the parasites, one can 100% accurately identify these species. The three groups of parasites were also significantly different in their ecology, manifested in their distinct host specificity.

[First record of species Dicranotaenia synsacculata Macko, 1988 (Cestoda, Hymenolepididae) of the goldeneye Bucephala clangula (Linneus, 1758) in Poland]. / Dicranotaenia synsacculata Macko, 1988 (Cestoda, Hymenolepididae)--tasiemiec gagola Bucephala clangula (Linneus, 1758) notowany po raz pierwszy w Polsce.

During parasitological studies of 32 specimens of the goldeneye Bucephala clangula L., twenty seven cestode specimens were found. Four of them, isolated from the jejunum of two young female hosts, were determinated as Dicranotaenia synsacculata Macko, 1988. We based on the shape of cirrus fused with sacculus accessorius internus, shape and size of scolex and other organs. This is the first record of this species in Poland.

Body condition and mercury concentration in apparently healthy Goosander (Mergus merganser) wintering in the Odra estuary, Poland.

Goosanders (Mergus merganser, ad, adult n = 42: M, males 33 and F, females 9; im, immature n = 17: M 8, F 9) were collected in 2005 at wintering site in the River Odra estuary (Poland). The body size (BM, body mass; BL, body length; KL, keel length), weights of organs (LM, liver; KM, kidneys; EM, encephalon), and two condition-related indices (BM/BL and BM/KL) were determined. Based on BM/BL and BM/KL indices, the birds were divided into 3 condition groups: A (very good), B (good), and C (moderate). Total mercury (Hg) concentrations (mg kg(-1) dry weight) were determined in liver, kidney, brain, breast muscle, and bone of 17 birds (ad, n = 8: 8 M, 1 F; im, n = 9: 6 M, 3 F). The highest Hg concentrations (in n = 17) were recorded in liver and kidney (14.7 and 9.9 mg kg(-1), respectively); the concentrations found in muscle and brain were lower (2.3 and 1.3 mg kg(-1), respectively), the lowest concentrations being typical of bone (0.08 mg kg(-1)). Mercury concentrations in the same organs of immature and adult goosanders, as well as males and females, did not differ significantly. On the other hand, distinct differences in Hg concentrations in the organs studied (except for the liver) were observed between individuals assigned to Group A (n = 11) and C (n = 6). Mercury levels were higher in the birds characterised by very good condition, which was most probably related to those birds being more efficient hunters, consuming higher amounts of Hg-containing fish. Significant and negative correlations between the muscle Hg concentration and the two condition-related indices (r > -0.70) were recorded in Group A only: the higher the concentration, the lower the BM/LM and BM/KL values.

[First record of Microsomacanthus tuvensis Spasskaya et Spasskii, 1961 (Cestoda, Hymenolepididae) in Poland]. / Microsomacanthus tuvensis Spasskaya et Spasskii, 1961 (Cestoda, Hymenolepididae) po raz pierwszy notowany w Polsce.

During standard parasitological studies of the tufted duck Aythya fuligula, obtained from fishermen from West Pomerania in December 2007, three cestode specimens were found in the jejunum of one male host. They were determinated as Microsomacanthus tuvensis (Spasskaya et Spasskii, 1961) on the basis of the cirrus's and cirrus sac's size and vagina's shape. This is the first record of this species in Poland.

Taxonomic structure of Digenea in wild ducks (Anatinae) from West Pomerania.

Parasitic fauna of birds connected with water environment, including digeneans, is relatively well researched in Poland. The exception, however, is West Pomerania, where those birds were not frequent objects of parasitological research until recently. The purpose of this work is to determine the taxonomic structure of the Digenea, parasitising wild ducks living in West Pomerania. The research material was 124 individuals of wild Anatinae (Anseriformes) belonging to 8 species: Anas strepera, A. crecca, A. platyrhynchos, Aythya marila, A. fuligula, Melanitta nigra, M. fusca and Mergus merganser. The ducks were obtained in the years 2001-2006 from small ponds near Szczecin, Lake Dabie, the Szczecin Lagoon and the Baltic Sea. The research showed the presence of 29 species of digeneans from 11 families: Paracoenogonimus ovatus Katsurada, 1914; Diplostomum mergi Dubois, 1932; D. parviventosum Dubois, 1932; D. phoxini (Faust, 1918); D. pusillum (Dubois, 1928); Ornithodiplostomum scardinii (Shulman in Dubinin, 1952); Echinochasmus spinulosus (Rudolphi, 1808); Echinoparyphium cinctum (Rudolphi, 1802); E. recurvatum (Linstow, 1873); Echinostoma miyagawai Ischii, 1932; E. revolutum (Fröhlich, 1802); Hypoderaeum conoideum (Bloch, 1782); Stephanoprora pseudoechinata (Olsson, 1876); Cryptocotyle concava (Creplin, 1825); C. lingua (Creplin, 1825); Leucochloridiomorpha lutea (von Baer, 1826); Catatropis verrucosa (Fröhlich, 1789); Notocotylus attenuatus (Rudolphi, 1809); Paramonostomum alveatum (Mehlis, 1846); Metorchis xanthostomus (Creplin, 1846); Prosthogonimus ovatus (Rudolphi, 1803); P. rarus Braun, 1901; Psilochasmus oxyurus (Creplin, 1825); Psilostomum brevicolle (Creplin, 1829); Psilotrema simillimum (Mühling, 1898); Bilharziella polonica (Kowalewski, 1895); Apatemon gracilis (Rudolphi, 1819); Australapatemon minor (Yamaguti, 1933); Cotylurus cornutus (Rudolphi, 1808).

[Helminths of Falco peregrinus Tunstall, 1771 from Szczecin area]. / Helminty dzikiego sokola wedrownego Falco peregrinus Tunstall, 1771 pochodzacego ze Szczecina.

In 2006, an emaciated female peregrine falcon Falco peregrinus was found near its nest, and died soon after. Parasitological research involved digestive tract and respiratory system, kidney and liver. In air sacs, nematode Serratospiculum tendo (Nitzsch, 1857), which causes the falcon disease serratospiculiasis, was found, and in the digestive tract trematodes Strigeafalconis Szidat, 1928, Conodiplostomum spathula (Creplin, 1829), and a cestode Cladotaenia cylindracea (Bloch, 1782).

[Preliminary studies on the cestodofauna of goosander Mergus merganser L., 1758 from West Pomerania]. / Wstepne badania cestodofauny nurogesia Mergus merganser L., 1758 z Pomorza Zachodniego.

The research included 54 individuals of the goosander Mergus merganser L., 1758 (Anseriformes, Mergini), wintering on Lake Dabie within the administrative limits of Szczecin. Seven species of cestoda from two families were found in those ducks. Two species from the family Diphyllobothriidae were recorded: Ligula intestinalis (Linnaeus, 1758) and Schistocephalus solidus (Müller, 1776), and five species from family Hymenolepididae: Dicranotaenia mergi Yamaguti, 1940, Fimbriaria mergi Grytner-Ziecina et Cielecka, 1995, Microsomacanthus vistulae (Czaplinski, 1960), Retinometra macracanthos (von Linstow, 1877) oraz Tschertkovilepis tenuirostris (Rudolphi, 1819). Founding species Dicranotaenia mergi is the first observation of this type in Poland.

[Digenea in Melanitta fusca and M. nigra (Mergini, Anseriformes) from the Baltic Sea]. / Digenea Melanitta fusca i M. nigra (Mergini, Anseriformes) z Morza Baltyckiego.

Ten individuals of Melanitta fusca and M. nigra (Mergini, Anseriformes) each, wintering at the Polish Baltic coast, were examined for the presence of parasites. M. fusca yielded a total of 197 helminths, including 20 digeneans and 177 nematodes. The M. nigra individuals examined were found to support 923 helminths, including 62 digeneans, 860 nematodes, and a single cestode. M. fusca were hosts to the digeneans: Cryptocotyle concava, Notocotylus attenuatus and Psilostomum brevicolle. Digenea found in M. nigra represented: C. concava and Paramonostomum alveatum. The prevalence of P. brevicolle infection (60%) was higher than that of other digeneans; the maximum infection intensity was 40 C. concava individuals in a single M. nigra.