Brown trout (Salmo trutta) eggs with eyed embryos

On Tuesday 8 December Kalle Filipsson, RivEM PhD student, will present his work on how elevated temperatures and predator presence during egg incubation affect development and behaviour of brown trout. The seminar starts at 13:15 and will be streamed live on Zoom. Contact Kalle ( if you are interested in attending the seminar, and he will send you a link.

Jeff Marker and Jeanette Karlsson (research assistant) electrofishing in a small stream.

On Tuesday 1 December Jeffery Marker, RivEM PhD student, will be giving a talk where he presents the plans for his PhD project.

The seminar is held on Zoom and starts at 13:15. Everyone is welcome to attend the seminar. Contact Jeff ( or Olle Calles ( if you want to attend, and they will send you a link.

Rachel Bowes (RivEM PostDoc) and colleagues have studied the downstream passage of several migrating fish species during spring and fall 2020. Here she writes about their work:

Laxeleratorn at Vattenfall’s Research & Development facility in Älvkarleby

“Dams are like giant road blocks for fish in rivers. It is not always feasible or realistic to remove a dam to restore fish movement throughout rivers, so we need to design detours around them.

When going downstream we call this detour past the dam a bypass. The question we are asking is: How can we design a better bypass for multiple fish species to be able to move downstream past a dam more easily and efficiently? To test this, we are using the Laxeleratorn at Vattenfall’s Research & Development facility in Älvkarleby. We are testing Silver Eels, Salmon, and Roach fish species. Changing the design of the bypass and amount of water flowing through it, we hope to find out what combination creates the optimal bypass for these fish species.”

European eel (Anguilla anguilla)

Lutz Eckstein, professor at Karlstad University, is involved in two recently published papers, studying the effects of invasive Garden Lupine (Lupinus polyphyllus) on vegetation and seed bank of mountain meadow plant communities.

The first paper together with Wiebke Hansen (first author), Julia Wollny, Annette Otte and Kristin Ludewig, published in the journal Biological Invasions (, found that the invasion of Garden Lupine homogenizes vegetation composition. The similarity among plots increased with increasing lupine cover in three different vegetation types. L. polyphyllus affected species diversity in terms of richness and effective species number but in rather complex ways, i.e. plots with low to intermediate lupine cover had higher species diversity than control plots. Probably, the invasion though Garden Lupine is linked to significant species turnover. A very clear effect was found for community-weighted means of species trait. In all three vegetation types studied, the canopy height of the community increased with increasing lupine cover, whereas especially in the low-productive Nardus grasslands, leaf dry matter content decreased and specific leaf area increased. Thus, the Garden Lupine shifted the suite of community traits towards more competitive trait values. This may lead to overall more productive plant communities from which rare, low-growing herbs and grasses will disappear.

Germination experiment from the seed bank study in the paper published in Restoration Ecology. Photo: Kristin Ludewig

The second paper with Kristin Ludewig (first author), Wiebke Hansen, Yves Klinger, and Annette Otte, published in the journal Restoration Ecology (, analyzed the effects of increasing cover of Garden Lupineon the seed bank of mountain meadows, and the potential of the seed bank of these stands for active restoration of mountain meadows in terms of species composition and number. The authors conducted a seed bank analysis on 84 plots with increasing cover of L. polyphyllus in three mountain-meadow types of the Rhön Biosphere Reserve, Germany. Seedlings from 119 species germinated from the seed bank samples, including 17 Red List species but only a few seedlings of L. polyphyllus. While the influence of L. polyphyllus on the current vegetation was visible, no effects on the seed bank were apparent. L. polyphyllus had no influence on total seed density, seed density of typical mountain-meadow species, or species numbers in the seed bank. Only the seeds of the Red List species were significantly related to the cover of L. polyphyllus. The authors conclude that the seed bank offers potential for active restoration of species-rich mountain meadows, but species absent from the seed bank have to be added by other measures.

Kristin Ludewig, Wiebke Hansen and Yves Klinger will presents these and other results from a large restoration project in the UNESCO Rhön Biosphere Reserve at the RivEM week.

Coming up: RivEM week

Posted by Jacqueline Hoppenreijs | RivEM week

RivEM (NRRV) invites you to the first annual RivEM week, where KAU researchers and international guests will present and discuss some of the exciting projects we have been working on! From 17 to 20 November, you are welcome to attend presentations and participate in discussions and workshops. Every session covers a different ecological research theme during the week.

Find more info on and sign up for one or more sessions via!

Biologi på Karlstads universitet anordnar en karriärdag för biologistudenter onsdagen 25 november, fylld med presentationer och diskussioner med potentiella arbetsgivare, helt online. Läs mer nedan, välkommen och glöm inte att anmäla dig!

Henry recently started his PhD at Karlstad University. Here, he writes about his previous work and what he intends to do as a PhD student at Karlstad University:

Hi! I’m one of the new additions to the RivEM group at Karlstad University. I’ll be working with the RIBES project, where the bulk of my position focuses on habitat alterations of rivers and fish community responses. Academically, I had excellent experiences studying at the University of Wisconsin-Stout for my undergraduate and the University of Nebraska-Lincoln for my masters. Outside of the academic environment I had many incredible experiences, often dealing with natural resources or geographic information systems. Up until now, I have performed research in seven states, four countries among two continents, and worked for three U.S. government agencies (e.g., NPS, USFWS, USGS), a state government, and a local government as well as a handful of universities. 

Research-wise, my work has primarily dealt with freshwater ecology and fisheries, more often from a field perspective. Still, there were undoubtedly plenty of lab experiences too (but I do find the field more fun!). I would say my view of my research goals has changed drastically over the last ten years. I originally got started doing micro-satellite work with brook trout trying to optimize PCR reactions, ultimately answering population genetics questions. During my undergrad, the summers were a full immersion in the diversity of applied research in freshwater systems. These include dealing with invasive and non-native species throughout the Rocky Mountains (e.g., lake trout and zebra mussels in Yellowstone National Park, bullfrogs in the Yellowstone River, rainbow trout in the Crazy Mountains). On the other end of this spectrum, I have assisted with recovery efforts and management of endemic and endangered species (e.g., Higgins’ eye pearlymussel in the Mississippi River, pallid sturgeon in the Platte River, lake trout, and native lamprey recovery in the Great Lakes Basin, Bonneville cutthroat trout in Idaho). These projects were eye-opening because they tended to be outside of the academic setting. I observed how people outside of academia used research to help fix problems in socio-ecological systems.

Holding a pallid sturgeon caught during Platte River monitoring project.

My master’s degree focused on channel catfish long-distance movements in an internationally managed ecosystem (Lake Winnipeg Acoustic Telemetry Project) compounded with the difficulties of managing a mixed-use fishery. The foundation of this problem was ecological, while the problem’s tradeoffs were socially and economically dependent. I addressed this problem with a Bayesian modeling framework to quantify movement and an ecosystem services approach to investigate alternative management options (in preparation for publication). These broader system-wide issues helped inspire my Aquatic Sciences publication, highlighting the importance of a proactive management paradigm concerning fragmented rivers and aging reservoir ecosystems.

I think now I have gone off the deep end into the quantitative realm. Exposure to Bayesian statistics has me wanting more out of the models the everyday ecologist is trying to wrestle in R. I think finding a balance between well-designed field sampling campaigns and well crafted statistical techniques will be my new focus for the next few years.

On tuesday 27 October (tomorrow) Patrik Andreasson (Adjunct Professor, Luleå University of Technology; Specialist, Vattenfall AB) will give a seminar titled “Fish diagnostics by image recognition using machine learning (AI)”.

The seminar starts at 13:15 and will be held via zoom. Everyone who wants to are welcome to attend the seminar. Contact Olle Calles ( to receive a zoom link to the seminar.

Image recognition using AI, as a tool for fish identification, was mentioned on the Swedish news earlier this year. Follow this link to to watch a short video and to read more about the project (in Swedish).

Louis recently started his PhD at Karlstad University. Here, he writes about his previous work and what he intends to do as a PhD student at Karlstad University:

Hei! My name is Louis Addo. I recently joined the RivEM research group as a new PhD student. My background and skills cut across agricultural engineering (from University of Ghana, Legon-Ghana), hydropower development (from Norwegian University of Science and Technology), water engineering and fish habitat modeling (from University of Oulu). My experience with fish habitat modeling was with Finland’s Centre for Economic Development, Transport and the Environment (Ely-Center) in Oulu. With Ely-Center as a master’s thesis worker and later a 1 month contract as an environmental designer, I researched on the effects of short-term regulation on habitat conditions of brown trout, Salmo trutta in the lowermost part of the Kalajoki River (a river located in the Northern Ostrobothnia region of Finland) and possibilities for mitigation. This project was an eye-opener to the use 2D hydrodynamic modelling and fish habitat modelling as a river management tool to protect the river ecosystems of trout under hydropeaking conditions.

As a new PhD student with the RivEM research group, my contribution will mainly be directed towards ecological and individual-based modelling of river ecosystems. This will directly involve modelling of Atlantic salmon and brown trout habitat in the lower part of the Gullspång River (a tributary to the lake Vänern in Sweden) under hydropeaking conditions. It is my future desire that the outcome of this research will contribute to solving real-world conservation problems related to river ecosystems. My supervisors will be John Piccolo (professor), Johan Watz (docent), and Steve Railsback (adjunct professor). As hobbies, my passion for flying and general aviation drives me to fly drones although not a pro yet 🙂 I love to watch and play soccer as well.

Our former PhD student Anna Hagelin and several other researchers, amongst them Larry Greenberg, Olle Calles and Eva Bergman, recently published a new paper in the Canadian Journal of Fisheries and Aquatic Sciences.

They examined fishway passage of landlocked Atlantic salmon in River Klarälven, Sweden and brown trout in River Gudbrandslågen, Norway, and the influence of prior experience on passage success in 2012 and 2013. Fishway trap efficiency varied from 18 to 88% and was influenced by river discharge. Most salmon (81%) entered the fishway trap on days without spill, and salmon moved from the turbine area to the spill zone when there was spill, with small individuals showing a stronger reaction than large fish. Analysis of fish with and without prior trap experience showed that a higher percentage of the “naïve” fish (70% of salmon and 43% of the trout) entered the fishway traps than the “experienced” ones (25% of the salmon and 15 % of the trout). Delays for fish that entered the trap ranged from 3-70 days for salmon and 2-47 days for trout.

The paper is not publicly accessible, but can be requested via ResearchGate.