The seasonal diet composition of otters (Lutra lutra) living by an eutrophic fish pond system, a wetland alder forest, and a slow-flowing stream located in south-west Hungary was investigated by spraint analysis (n = 801, 116 and 234 samples respectively). Both percentage relative frequency of occurrence (O%) and biomass (B%) of food items (calculated by coefficients of digestibility) were estimated. The food composition of the otters living by the three areas differed significantly (PAstacus spp.) was dominant (54 O% and 62 B%). Close correlation was found between relative frequency of occurrence and biomass of food items.
In this study we examine differences in the occurrence of life history stages of the destructive fish ectoparasite Argulus foliaceus (L., 1758) on eight fish species (stickleback, rudd, roach, gudgeon, bream, tench, crucian carp and common carp) sampled from a mixed-species recreational fishing lake on nine occasions during late spring and summer. Total numbers of A. foliaceus, as well as the number of larval, juvenile and adult parasite stages, from each fish were recorded along with the fish species. Lice generally exhibited an aggregated distribution approximating a negative binomial distribution. Significant differences in the prevalence, intensity and intensity frequency distribution were observed between life history stages and between host species. In general, all life history stages of A. foliaceus exhibited an over-dispersed distribution. However, larval lice did show some degree of aggregation particularly within the stickleback samples. Infection data for parasite larval stages suggested that sticklebacks are more likely to be infected than other host species. For adult lice, however, carp appeared to be the main host. We propose that A. foliaceus infection characteristics are predominantly determined by the level of host exposure to the parasite and its life history stages (larval, juvenile and adult) rather than by an innate difference in host susceptibility related to individual host factors such as immune responses. We conclude that host exposure is determined by the parasite-host behavioural interplay related to species-specific ecology and behavioural traits such as microhabitat preference and normal swimming speed.
Recently, based on a limited morphological characterisation and partial 18S rRNA gene sequence, Jiang et al. (2019) described Trypanosoma micropteri Jiang, Lu, Du, Wang, Hu, Su et Li, 2019 as a new pathogen of farmed fish. Here we provide evidence based on the expanded sequence dataset, morphology and experimental infections that this trypanosome does not warrant the establishment as a new species, because it is conspecific with the long-term known Trypanosoma carassii Mitrophanow, 1883, a common haemoflagellate parasite of freshwater fish. The former taxon thus becomes a new junior synonym of T. carassii.
Bronzová plastika: nahá Ceres (koruna z klasů) sedí na rybě, v levici srp, v pravici klasy. and V Ovidiově Kalendáři (4, 401-402) se vysvětluje, proč antické sochy Ceres držely obilné klasy.
Kašna (Danubius-kút), původně roku 1883 instalována na Kálvin tér (u Národního muzea), roku 1944 těžce poškozena a rozebrána, 1955 - 1959 restaurována (Dezső Győri). Jediná originální dochovaná plastika z původní kompozice je dnes ve dvoře domu č. 9 na Kálvin tér. Kašna je třípatrová, na vrcholu postava vousatého muže, jedna noha spočívá na delfínovi, v ruce drží veslo (personifikace Dunaje), na bázi pod mísou fontány tři sedící ženy - personifikace řek:Žena s překříženýma nohama držící síť s rybami - Tisza; žena s nohou spočívající na nádobě, v náručí a ve vlasech mušle - Dráva; žena s vavřínovým věncem na hlavě - Száva., Budapest köztéri 1987, č. 93; Déry 1991, s. 35; Buza 1994, s. 35 - 38., and Kašna (Danubius-kút) je sochařskou alegorií největších maďarských vodních toků. Dunaj může být chápán jako symbol otce města, stejně jako Tiber v Římě (Vergil, Aen., VIII, 31 -67), socha je zde obdobně zpracována do podoby starého muže. Personifikace říčních božstev je antickým přínosem, tato božstva jsou však v řecké mythologii vždy mužského rodu, později byla zobrazována na římských mincích, od renesance jsou alegorie řek nejčastějším výzdobným prvkem fontán.
The larval development of the nematode Contracaecum rudolphii (Rudolphi, 1819), a common parasite of the proventriculus of cormorants, was experimentally studied. Within the eggs cultivated in freshwater under laboratory temperatures of 20-22 °C, the developing larva undergoes two moults on days 4-5, attaining the third larval stage. Most of the ensheathed third-stage larvae, 291-457 µm long, hatch spontaneously from egg shells on days 5-6. Experiments have indicated that hatched ensheated third-stage larvae and those still inside egg capsules are already infective to copepods and fishes, which both can be considered paratenic (metaparatenic) hosts. Five copepod species, Acanthocyclops vernalis, Cyclops strenuus, Ectocyclops phaleratus, Eucyclops serrulatus and Megacyclops viridis, the isopod Asellus aquaticus and small carps Cyprinus carpio were infected by feeding them these larvae. In addition, 9 fish species, Alburnoides bipunctatus, Anguilla anguilla, Barbatula barbatula, Cyprinus carpio, Gobio gobio, Perca fluviatilis, Phoxinus phoxinus, Poecilia reticulata and Tinca tinca, were successfully infected by feeding them copepods previously infected with C. rudolphii third-stage larvae. In fishes, larvae from copepods penetrate through the intestinal wall to the body cavity, where, in a few weeks, they become encapsulated; the larvae substantially grow in fish, attaining the body length up to 4.87 mm. In carp fry, the nematode third-stage larvae survived for about 15 months (up to 18 months in fish infected directly, i.e., without copepods). One small cormorant (Phalacrocorax carbo sinensis) was successfully infected by feeding it with copepods harbouring C. rudolphii third-stage larvae.
Diet composition and feeding habits of Eurasian otters (Lutra lutra) living on three moors (Baláta, Nagyberek and Fehérvíz) in Hungary were studied over two years using spraint analysis (n = 199, 503 and 315 samples from the three moors, respectively). The food and presence of otters in the first moderate and second drought year, when the moors dried during the summer period, generally differed. Area-dependent variations in the diet were also found. The primary food source was fish (biomass estimation for the first and second year: Baláta 94.4% and 99.9%; Nagyberek 93.9% and 71.5%; Fehérvíz 66.4% and 82.1%). Most fish (mean: 94.6–99.9%) were small-sized (below 100 g in weight), and the most frequently taken species was Carassius spp. On moors, which are dependent on rainfall and ground-water only, during or after periods of drought otters temporarily changed their diet from optimal prey (fish) to sub-optimal prey (e.g., waterfowl) and they often left the habitat entirely. On moors with small canals, during periods of drought otters kept fish as the dominant food source, and weathered out extreme environmental local conditions.
Henneguya pilosa sp. n., a new species of myxosporean from the gill filaments of the white piranha, Serrasalmus altuvei Ramirez, 1965 (Characidae), a freshwater teleost fish collected in the Zoological Garden of the city of Teresina (Piauí), Brazil, is described from light and transmission electron microscope observations. This myxosporean produced small plasmodia (up to 0.2 mm in diameter), each one containing all life-cycle stages of the parasite, including numerous spores. The spores, laterally compressed, averaged 54.2 (52.3-56.0) µm in total length and consisted of two unequal valves adhering together along the suture line and two caudal processes. The spore body measured 21.1 (20.0-23.1) µm in length, 5.9 (5.5-6.3) µm in width, and 2.2 (1.9-2.6) µm in thickness. The two equal ellipsoidal polar capsules of 7.4 (7.1-7.6) µm long and 1.2 (1.0-1.3) µm wide possessed a polar filament with 11-12 (rarely 13) turns. All surfaces of the spores were covered with a tightly adherent complex network of numerous densely ramified granulo-fibrillar masses, the longest measuring 1.5 µm long, observed around the caudal processes. The prevalence of infection was 30%. The taxonomic affinities of this parasite with other of the same genus in freshwater South American fish species are discussed.
The evaluation of resident fi sh communities is an important component of the ecological status assessment in aquatic habitats. Despite signifi cant water quality improvement in the Czech Republic in the last decade, several important pollution sources in the Elbe River basin remain. The aim of the study was to evaluate fish community in a chronically polluted part of the channelized lowland Elbe River and its potential indicative capability. The effluent from both industrial and municipal sewage treatment plant exhibited low pH, high conductivity and wide set of organic compounds (PAH, PCB, DDT etc.). Ecological characteristics of fi sh communities were obtained by boat electro fishing at selected sites in four inter-weir sections in July 2005 and 2006. Relatively high fish species richness (24 species) was observed in both seasons. Generalists (bleak, roach, chub) form the majority of the fish community in all four sections. There was no significant difference in fish species richness or density among study sections (river segments between weirs) even with a high level of measured organic compounds at the pollution inlet. Signifi cant differences in fish species richness and density were registered among individual sites within study sections. Sites downstream the weirs had signifi cantly higher species richness and density than the other two sites in the middle and upstream weirs. Fish community does not display any indicative remarks concerning water pollution, or in the case of mid-size river, sampling strategy was not effi cient to recognize it. Channelization and regulation of the study stretch of the Elbe River seems to be the most important determinant of fi sh community structure.