The emergence of cercariae from infected mollusks is considered one of the most important adaptive strategies for maintaining the trematode life cycle. Short transmission opportunities of cercariae are often compensated by periodic daily rhythms in the cercarial release. However, there are virtually no data on the cercarial emergence of bird schistosomes from freshwater ecosystems in northern ...

Subarctic populations of brown trout (Salmo trutta) are often heavily infected with cestodes of the genus Diphyllobothrium, assumedly because of their piscivorous behavior. This study explores possible associations between availability of fish prey and Diphyllobothrium spp. infections in lacustrine trout populations. Trout in i) allopatry (group T); ii) sympatry with Arctic charr (Salvelinus alpinus) ...

We review three long‐term research programs performed over the last four decades on the ecology and management of oligotrophic lake systems with different fish communities at 69&deg; N in Norway. Through whole‐lake perturbation experiments, intensive culling of stunted fish removed 35 tons (1984–1991) of Arctic charr <i>Salvelinus alpinus</i> in Takvatn (15 km²) and 153 tons (1981–1983, ...

The trophic niches of Arctic charr and brown trout differ when the species occur in sympatry . Their trophically transmitted parasit es are expected to reflect these differences. Here , we investigate how the infections of Diphyllobothrium dendriticum and Diphyllobothrium ditremum differ between charr and trout. These tapeworms use copepods ...

Results from 2004 showed that the lice infection pressure varied between the different monitoring stations in time and space and that the overall pattern was moderate to high infection in all areas. This is in spite of the fact that the fish farmers have improved their implementation of delousing strategies in fish farms. The density of fish farms is high all along the coast. The total biomass may ...

Some fish parasites constitute severe management problems as they may cause mortality of their fish host or are important zoonoses of humans. Parasite assessments are therefore critical to keep track of infections. If conventional sampling techniques can be simplified, parasite assessments might be easier to obtain, less time-consuming and more extensive. In this study, we compare the ...

Overbefolka fiskebestander er et stort problem i mange av våre innsjøer. Det typiske kjennetegnet er en stor tetthet av gammel, småvokst og mager fisk, gjerne med en høy infeksjon av parasitter. Hardt uttynningsfiske har vært foreslått som et mulig botemiddel, men selv om det har vært gjort mange forsøk på å komme problemet til livs, er det få som har lyktes. Denne rapporten ...

Direct consumption on free-living cercariae stages of trematodes by non-host organisms interferes with trematode transmission and leads to reduced infections in the next suitable hosts. Consumer functional responses provide a useful tool to examine relationships between consumption rates and ecologically relevant prey densities, whilst also accounting for abiotic factors that likely influence ...

Tracking individual variation in the dynamics of parasite infections in wild populations is often complicated by lack of knowledge of the epidemiological history of hosts. Whereas the dynamics and development of Gyrodactylus salaris Malmberg, 1957, on Atlantic salmon, Salmo salar L., are known from laboratory studies, knowledge about infection development on individual wild fishes is currently sparse. ...