Jan Baer
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View article: Drivers of the range expansion of the European catfish (<i>Silurus glanis</i>) within its native distribution
Drivers of the range expansion of the European catfish (<i>Silurus glanis</i>) within its native distribution Open
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 charact…
View article: Proliferative Kidney Disease in Sympatric Naturally Reproducing Populations of Rainbow and Brown Trout in Southern Peri‐Alpine Germany
Proliferative Kidney Disease in Sympatric Naturally Reproducing Populations of Rainbow and Brown Trout in Southern Peri‐Alpine Germany Open
The decline of central European salmonid populations is exacerbated by global warming impacts on disease and interspecific competition. In this context, sympatric naturally reproducing populations of rainbow trout Oncorhynchus mykiss and b…
View article: New insights into the collapse of Upper Lake Constance whitefish (<i>Coregonus wartmanni</i>) and the impact of commercial fisheries management
New insights into the collapse of Upper Lake Constance whitefish (<i>Coregonus wartmanni</i>) and the impact of commercial fisheries management Open
The whitefish Coregonus wartmanni is the key fishery resource in Upper Lake Constance (ULC), one of Central Europe’s largest lakes. A significant stock decline resulted in the closure of the commercial whitefish fishery in 2024. Reasons fo…
View article: Characterization of specialist European catfish anglers in southern Germany: Implications for future management
Characterization of specialist European catfish anglers in southern Germany: Implications for future management Open
The European catfish (Silurus glanis) is a large apex predator native to Eastern Europe. Increasing populations within and outside the species' native range in recent years, and its popularity with recreational anglers are fueling discussi…
View article: How diverse is the toolbox? A review of management actions to conserve or restore coregonines
How diverse is the toolbox? A review of management actions to conserve or restore coregonines Open
Over the past centuries, coregonines have been exposed to a range of stressors that have led to extinctions, extirpations, and speciation reversals. Given that some populations remain at risk and fishery managers have begun restoring coreg…
View article: Response of European whitefish embryos to thermal conditions diverges between peri-alpine populations
Response of European whitefish embryos to thermal conditions diverges between peri-alpine populations Open
Peri-alpine lakes are vulnerable to climate warming. Water temperature in these lakes has increased and will likely continue in the coming decades, questioning the fate of inhabiting aquatic populations. Understanding how coregonine fishes…
View article: Escaping malnutrition by shifting habitats: A driver of three‐spined stickleback invasion in Lake Constance
Escaping malnutrition by shifting habitats: A driver of three‐spined stickleback invasion in Lake Constance Open
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 …
View article: Massive Fish Kill After the Discharge of Artificial Fertilizer into a Species Rich River in Southwestern Germany: a Conservation Case Study
Massive Fish Kill After the Discharge of Artificial Fertilizer into a Species Rich River in Southwestern Germany: a Conservation Case Study Open
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 fir…
View article: Stable isotope values and trophic analysis of invasive three-spined stickleback in Upper Lake Constance points to significant piscivory
Stable isotope values and trophic analysis of invasive three-spined stickleback in Upper Lake Constance points to significant piscivory Open
The three-spined stickleback Gasterosteus aculeatus was introduced into Lake Constance in the 1940s and occupied a limited range until late 2012. Since then the species has expanded from a solely littoral habitat in Upper Lake Constance, b…
View article: Does treatment of brown trout with the parasite causing <scp>PKD</scp> increase stocking success and boost resilience against the disease?
Does treatment of brown trout with the parasite causing <span>PKD</span> increase stocking success and boost resilience against the disease? Open
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 t…
View article: A matter of time—Efficacy of whitefish stocking in a large pre‐alpine lake
A matter of time—Efficacy of whitefish stocking in a large pre‐alpine lake Open
The tradition of stocking whitefish ( Coregonus spec.) is widespread throughout Europe and dates back more than a century in some lakes. Despite its broad acceptance as a management action, stocking success is less often studied and might …
View article: Endangered spined loach <i>Cobitis</i> species in Southwest Germany: A complex network of native, hybrid and newly emerged populations
Endangered spined loach <i>Cobitis</i> species in Southwest Germany: A complex network of native, hybrid and newly emerged populations Open
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 critica…
View article: raw data
raw data Open
uploaded are raw data of eDNA and microsatellite analyses and landmarks used in morphometric analyses. For detailed information see XXX.
View article: Cryptic persistence and loss of local endemism in <scp>L</scp>ake <scp>C</scp>onstance charr subject to anthropogenic disturbance
Cryptic persistence and loss of local endemism in <span>L</span>ake <span>C</span>onstance charr subject to anthropogenic disturbance Open
In the welcome circumstance that species believed extinct are rediscovered, it is often the case that biological knowledge acquired before the presumed extinction is limited. Efforts to address these knowledge gaps, in particular to assess…
View article: Turning summer into winter: nutrient dynamics, temperature, density dependence and invasive species drive bioenergetic processes and growth of a keystone coldwater fish
Turning summer into winter: nutrient dynamics, temperature, density dependence and invasive species drive bioenergetic processes and growth of a keystone coldwater fish Open
A combination of global changes such as species invasions, climate change and nutrient pollution have altered ecosystems, food webs and the bioenergetic processes that control growth. These changes are especially pronounced in freshwater e…
View article: Stickleback mass occurrence driven by spatially uneven parasite pressure? Insights into infection dynamics, host mortality, and epizootic variability
Stickleback mass occurrence driven by spatially uneven parasite pressure? Insights into infection dynamics, host mortality, and epizootic variability Open
Since 2012, a massive invasion of the three-spined stickleback ( Gasterosteus aculeatus ) has taken place into the pelagic area of Lake Constance. This species, which had previously been restricted to the littoral zone, is now the dominant…
View article: Signs of the times: Isotopic signature changes in several fish species following invasion of Lake Constance by quagga mussels
Signs of the times: Isotopic signature changes in several fish species following invasion of Lake Constance by quagga mussels Open
Since the arrival of the invasive quagga mussels Dreissena rostriformis bugensis in Lake Constance, significant changes in the zooplankton and benthic invertebrate community were observed. Five years later the quagga mussel has become the …
View article: Size matters? Species‐ and size‐specific fish predation on recently established invasive quagga mussels <i>Dreissena rostriformis bugensis</i> Andrusov 1897 in a large, deep oligotrophic lake
Size matters? Species‐ and size‐specific fish predation on recently established invasive quagga mussels <i>Dreissena rostriformis bugensis</i> Andrusov 1897 in a large, deep oligotrophic lake Open
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 fie…
View article: Morphometric data: Cryptic persistence and loss of local endemism in Lake Constance charr subject to anthropogenic disturbance
Morphometric data: Cryptic persistence and loss of local endemism in Lake Constance charr subject to anthropogenic disturbance Open
In the welcome circumstance that species believed extinct are rediscovered, it is often the case that biological knowledge acquired before the presumed extinction is limited. Efforts to address these knowledge gaps in particular to assess …
View article: All day-long: Sticklebacks effectively forage on whitefish eggs during all light conditions
All day-long: Sticklebacks effectively forage on whitefish eggs during all light conditions Open
The three-spined stickleback Gasterosteus aculeatus invaded Lake Contance in the 1940s and expanded in large numbers from an exclusively shoreline habitat into the pelagic zone in 2012. Stickleback abundance is very high in the pelagic zon…
View article: Feeding Ecology of Invasive Three-Spined Stickleback (Gasterosteus aculeatus) in Relation to Native Juvenile Eurasian Perch (Perca fluviatilis) in the Pelagic Zone of Upper Lake Constance
Feeding Ecology of Invasive Three-Spined Stickleback (Gasterosteus aculeatus) in Relation to Native Juvenile Eurasian Perch (Perca fluviatilis) in the Pelagic Zone of Upper Lake Constance Open
The fish community of Lake Constance, a large, deep, oligotrophic lake has undergone drastic changes in recent years, with the sudden rise to dominance of invasive three-spined stickleback ( Gasterosteus aculeatus ) in the pelagic zone, a …
View article: Current and projected impacts of the parasite <i>Tetracapsuloides bryosalmonae</i> (causative to proliferative kidney disease) on Central European salmonid populations under predicted climate change
Current and projected impacts of the parasite <i>Tetracapsuloides bryosalmonae</i> (causative to proliferative kidney disease) on Central European salmonid populations under predicted climate change Open
Proliferative kidney disease (PKD) caused by the myxozoan parasite Tetracapsuloides bryosalmonae is an emerging salmonid disease implicated in recent declines in salmonid populations. Laboratory experiments have shown that the clinical sym…
View article: Long-term changes in body condition and gillnet selectivity in Lake Constance pelagic spawning whitefish (<i>Coregonus wartmanni</i>)
Long-term changes in body condition and gillnet selectivity in Lake Constance pelagic spawning whitefish (<i>Coregonus wartmanni</i>) Open
The body condition of Lake Constance pelagic spawning whitefish (Coregonus wartmanni) has changed substantially during the past century and altered the length-based selectivity of gillnets. Linked hierarchical models using Bayesian inferen…
View article: Quantification of alizarin red S uptake in coregonid eggs after mass‐marking
Quantification of alizarin red S uptake in coregonid eggs after mass‐marking Open
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 mar…
View article: Intersectorality in the governance of inland fisheries
Intersectorality in the governance of inland fisheries Open
One of the defining characteristics of inland fisheries is that they are closely impacted by other essential human activities that rely on the same fresh or brackish water ecosystems, such as hydroelectricity generation and irrigated agric…
View article: Invasion strategy and abiotic activity triggers for non-native gobiids of the River Rhine
Invasion strategy and abiotic activity triggers for non-native gobiids of the River Rhine Open
The 24 hour activity patterns of three non-native gobiids (round goby Neogobius melanostomus, Western tubenose goby Proterorhinus semilunaris and bighead goby Ponticola kessleri) were assessed over 46 consecutive months between 2011 and 20…