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.

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.

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.

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.

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 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.

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.

[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 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.

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.

Nematofauna of ducks of the genus Melanitta (Mergini, Anseriformes) from the south Baltic Sea.

A total of 10 individuals each of the common scoter (Melanitta nigra) and the velvet scoter (M. fusca) were examined for parasites. The scoters are marine ducks wintering at the south-western coast of the Baltic Sea. The scoters were found to be infected with 5 nematode species. While the common scoter supported Amidostomoides monodon, Epomidiostomum uncinatum, Tetrameres sp. and Echinuria hypognatha, the velvet scoter were hosts to A. monodon, E. hypognatha, and Streptocara crassicauda. This is the first record of Echinuria hypognatha in Poland.

[Biological and ecological background of nematode fauna structure formation in the alimentary tracts of wild Anatinae ducks in north-western Poland]. / Biologiczne i ekologiczne uwarunkowania ksztaltowania sie struktury nematofauny przewodu pokarmowego dzikich kaczek (Anatinae) w pólnocno-zachodniej Polsce.

The study involved a total of 250 wild ducks representing 17 species of three ecologically different tribes: the Anatini (113 individuals), the Aythyini (71), and the Mergini (66). The ducks, obtained mainly from fishermen and hunters, were examined for the presence of parasites, using the generally accepted methods. Analyses of nematode assemblage structure were conducted with methods described in the literature. In addition, significance of differences in intensity of infestation was determined in relation to the hosts' age and sex as grouping variables. Significance of differences in infestation prevalence was tested with the Pearson Chi2 test or its modifications (V-square test, Chi2 test with Yates' correction, and the exact Fisher's test), while the Mann-Whitney U test was applied to infestation intensity and relative density. Similarity coefficients were ordered using the cluster analysis module of the STATISTICA 6.0 computer software; Ward's algorithm was used for grouping, Euclidean distance being applied as the similarity measure. The ducks examined were found to host a highly diverse nematode assemblage, consisting of a total of 22 species representing the following 7 families: Amidostomatidae, Anisakidae, Ascarididae, Tetrameridae, Acuariidae, Dioctophymatidae, and Capillariidae, the core of the assemblage being formed by the following 7 species: Amidostomoides acutum, A. monodon, A. petrovi, Tetrameres fissispina, Echinuria uncinata, Eucoleus contortus, and Capillaria anatis. The assemblage of parasitic nematodes in the ducks examined was found to be characterized by a high organ specificity, as the parasites selected mainly the gizzard and proventriculus as their microhabitats (10 and 8 typical species, respectively) and firmly avoided the duodenum and cloaca. Individual parasite species were observed to show a clear preference with respect to location in the host's alimentary tract, which means that, for a distinct majority of the parasitic species, typical sites could be identified. No significant effects of host's age and sex on nematode infestation parameters could be revealed, although - in certain species - those variables proved of a key importance for their specificity. The nematodes showing a distinct preference towards young birds include E. uncinata and Ingliseria cirrohamata, a still higher specificity being displayed by T fissispina and A. petrovi (selectively parasitising young females) and C. anatis (selective with respect to young males). The species which were more frequently recorded in the ducks aged two years and more, particularly in the adult males, include A. monodon and A. acutum. A clear relationship between the ecology of a host and the structure of its parasitic nematode assemblage was observed. Each of the tribes was distinct in the specific nematofauna of its members, each nematofauna possessing its own well-expressed core. The nematofauna of swimming ducks (Anatini) consisted of 11 species, the core being formed by A. acutum, E. uncinata, T fissispina, and E. contortus. The diving ducks (Aythyini) were found to host 8 nematode species, the core being formed by A. petrovi, T. fissispina, and C. anatis. The nematofauna of the predacious Mergini was found to consist of as many as 17 species, although one of them (A. monodon) was a distinct dominant. The nematode fauna of those birds showed also a relatively high proportion of T. fissispina, the most polyxenic nematode, recorded in 10 host species of all the tribes studied. Although the problem of habitat partitioning between various components of a nematode assemblage could not be unambiguously resolved, it was evident that cases of co-occurrence involved mainly co-invasions at different sections of the alimentary tract of the same host, the strongest relations being found for those species that formed the core of a nematode assemblage. Co-invasions affecting a host's organ concerned almost exclusively representatives of the families Amidostomatidae and Acuariidae in the gizzard and those of the Tetrameridae and Acuariidae in the proventriculus. The similarities between nematofaunas of the ducks studied are only weakly related to the systematic position of the respective ducks; much stronger relationships with ecological characteristics (mainly food type and feeding habits) were revealed. It seems that this is why the nematofauna of Common Goldeneye is much more similar to that of the Aythyini than to that of the Mergini to which the species is taxonomically assigned.

[Intestinal digeneans of Gavia stellata (Pontoppidan, 1763) and Gavia arctica (Linnaeus, 1758) from West Pomerania, Poland]. / Digenea ukladu pokarmowego Gavia stellata (Pontoppidan, 1763) i Gavia arctica (Linnaeus, 1758) z Pomorza Zachodniego.

In 2000 and 2006 a total of 20 divers including 15 Gavia stellata and 5 Gavia artica from Pomeranian Bay and Szczecin Lagoon were examined. G. stellata were found to be infected with 3 digenean species: Stephanoprora pseudoechinata (Olsson, 1876), Cryptocotyle concava (Creplin, 1825) and Diplostomum gavium (Guberlet, 1922). G. arctica were host to Echinochasmus spinulosus (Rudolphi, 1809). This is the first record of Stephanoprora pseudoechinata in G. stellata and Echinochasmus spinulosus in G. arctica in Poland. The prevalence of S. pseudoechinata infection (46.7%) was higher than that of other digeneans.

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).

[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.

[Aythya fuligula--new host for Retinometra pittalugai Lopez-Neyra, 1932 (Cestoda, Hymenolepididae) recorded in Poland for the first time]. / Aythya fuligula--nowy zywiciel dla tasiemca Retinometra pittalugai Lopez-Neyra, 1932 (Cestoda, Hymenolepididae) po raz pierwszy notowanego w Polsce.

During standard parasitological studies of the tufted duck Aythya fuligula (Linnaeus, 1758), obtained from fishermen from West Pomerania, three cestode specimens were found in the jejunum of hosts. They were determined as Retinometra pittalugai (Lopez-Neyra, 1932) on the basis of the cirrus's size, shape of stylet and rostellar hooks. This is the first record of this species in Poland, since this parasite was earlier recorded only in Anas platyrhynchos f. dom., Aythya marila, A. ferina and Bucephala clangula in Spain, in Kamchatka and in Novosibirsk.

[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).

[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.

[Helminthofauna of the goosander Mergus merganser L., 1758 from the north-western Poland]. / Helmintofauna nurogesi Mergus merganser L., 1758 z pólnocno-zachodniej Polski.

The goosander, Mergus merganser, is a rare in Poland water bird (Anseriformes: Mergini). It eats fish and small invertebrates. The purpose of this study was a preliminary parasitological examination of the digestive tract of the goosander wintering on the Szczecin Lagoon. The research material were the parasites recovered from digestive tracts of 6 birds (two males and four females), which died during feeding in fishing nets in winter 2001. The birds were subject to standard parasitological examinations using commonly adopted methods. The trematodes and the cestodes found were preserved in 70% ethyl alcohol and subsequently stained using iron carmine (Cestoda) and borax alcohol carmine (Digenea) and then they were closed in Canada balsam. Nematodes were kept in 70% alcohol and cleared with 80% lactic acid or lactophenol. The parasite assemblages were analysed through calculating prevalence, intensity of infection, relative density and domination index. Also, the topic structure of the parasite assemblages or their habitat preferences in a host animal digestive tract were determined. The presently reported study detected a total of 1596 parasitic worms: digeneans (1086), tapeworms (410) and nematodes (100). Acanthocephalans were not found. Even though only a few goosanders were examined, the results show a high species richness of parasite assemblages consisting of 22 species, representing 21 genera. The following were deemed as definite dominants (superdominants): Diplostomum mergi Dubois, 1932; D. pusillum (Dubois, 1928); Microsomacanthus abortiva (von Linstow, 1904) and Schistocephalus solidus (Müller, 1776). Helminths were found in all birds with their great relative density and intensity of occurrence (266 parasites on average). As expected, the parasite assemblages were characterized by considerable topical specificity, probably resulting from the feeding preferences of the worms. The majority of helminths, including predominant part of flatworms, were found in duodenum and jejunum of ducks. Nematodes, on the other hand, colonized mainly the gizzard and proventriculus.