To study variables that may trigger the dispersion of the currently expanding European catfish in its native distribution limits, 42 individuals were captured from Upper Lake Constance (lentic) and 42 from two streaming tributaries (lotic), fitted with pressure and temperature loggers, and released at the site of capture (control: lotic or lentic) or into a new environment (lotic‐to‐lentic or lentic‐to‐lotic). Twenty‐seven fis...

Despite efforts to minimize human impact on rivers, native teleost fish and lamprey species communities in Germany remain threatened. The aim of the study was to quantify current species diversity in the study area, identify the level of deviation from realistic reference conditions, and characterize relevant drivers of diversity loss. Site-specific survey data were consolidated with reference fish community data, and selected...

The European catfish Silurus glanis L. continues to spread as an invasive species in Europe. Meanwhile, increasing abundance and range expansions are also suspected within its native distribution. The objective of this study was to characterize the feeding, growth and abundance of S. glanis in 12 lakes and 12 rivers within its European native range in relation to environmental changes that may explain population trends over ti...

Fatty acids, and especially long‐chain polyunsaturated fatty acids, are biologically important components in the metabolism of vertebrates, including fish. Essential fatty acids (EFA) are those that in a given animal cannot be synthesized or modified from precursors and must therefore be acquired via the diet. Because EFAs are often unevenly distributed in nature, this requirement may drive species to make behavioral or ecolog...

In the summer of 2015, large amounts of artificial fertilizer containing ammonium nitrate were accidentally discharged into the Jagst River along with water used to extinguish a serious fire. The incident caused a massive fish kill the first 25 km downstream of the spill and impacted fish density along a 50 km stretch of this sensitive and important river. In this study, the long-term effects of the accident on the local fish...

In Salmonidae, infections with the parasite Tetracapsuloides bryosalmonae may lead to a temperature‐dependent proliferative disease of the kidney (PKD). Trout that survive infection and recover become resistant to the disease. The use of this approach to improve brown trout ( Salmo trutta ) stocking success was tested in three PKD‐affected streams in southern Germany. Fish were treated using local spores of the parasite and ke...

Successful conservation of cryptic species such as representatives of the genus Cobitis presents a challenge for fishery managers. Only Cobitis taenia L. is currently assumed to occur in southwest Germany, where it is classified as critically endangered. Established genetic markers and eDNA analysis identified three Cobitis species in the study area. Cobitis taenia and Cobitis elongatoides were widely distributed in the Rhine...

Since its first appearance in Lake Constance in 2016 the invasive quagga mussel Dreissena rostriformis bugensis has come to dominate the mussel community and now occurs in hyperabundant densities over the whole lake bottom. A lake‐wide field study was conducted between 2019 and 2020 to obtain a systematic insight into the importance of this novel source of potential prey for the native fish community. In total 664 fish of 20 d...

Over the last two decades, an increasing number of reports have identified a decline in salmonid populations, possibly linked to infection with the parasite Tetracapsuloides bryosalmonae and the corresponding disease, that is, proliferative kidney disease (PKD). The life cycle of this myxozoan parasite includes sessile bryozoan species as invertebrate host, which facilitates the distribution of the parasite in running waters....

An easy method to measure the uptake rate of the persistent dye alizarin red S (ARS) during marking of whitefish eggs was established and used to measure the ARS content in three different whitefish species during and at the end of the marking procedure. Those values show that only 6–10% of the ARS in the marking solution will be absorbed by the eggs (0.0061–0.0119 mg per egg). Additional analyses 6, 15 and 36 months after mar...

The intensive aquaculture of salmonids is a relatively young discipline within the animal husbandry sector. It differs to terrestrial livestock farming in one obvious and fundamental aspect – the aquatic environment. Besides great advantages such as buoyancy, the fluid medium also poses specific challenges for fish and fish farmers. One issue identified as a central problem in aquaculture is the presence of undissolved particu...

Between 1951 and 1979, total phosphorous concentrations in Lake Constance increased from 7 to 87 μg L −1 . Following wastewater treatment, phosphorus levels were brought under control, returning to 7.6 μg L −1 by spring 2007. The biological and chemical data from 1980 to 2004 were first modelled by seasonal time series analyses and then used to create a general model. Excluding collinear variables allowed the data set to be co...