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)

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 (olle.calles@kau.se) 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 svt.se to watch a short video and to read more about the project (in Swedish).

As a member of the European consortium RIBES (River flow regulation, fish Behaviour and Status), the River Ecology and Management research group at Karlstad University invites applicants to three PhD positions on fish migration and passage in regulated rivers. In addition to the three PhD positions in Karlstad, RIBES also announces 12 more PhD positions in Belgium, Estonia, Germany, Italy and the UK as part of the same network.

Read more about the PhD positions and how to apply here!

Last application date is 31 May 2020.

To be eligible for one of the PhD positions in Karlstad, candidates cannot have resided in Sweden for 12 months or longer in the 3 years immediately before the recruitment date.

For more information about RIBES, check out our website!

River Klarälven in Värmland, Sweden

Karlstad University invites applications for three full-time PhD positions in ecology!


Two of the positions focus on applied aquatic conservation biology and aim to examine:

Position 1) Ecological effects of remedial measures in regulated rivers, e.g. implementation of fish passage solutions and dam removal, on diadromous fish species in southern Sweden.

Position 2) Reintroduction ecology of the freshwater pearl mussel and the thick-shelled river mussel and their host fishes in southern Sweden.

Read more and apply for the positions here, last application date is 31 January 2020.


The third position is on ecological and individual-based modelling and aims to:

i) Develop high-resolution spatially explicit maps of physical habitats in rivers, (ii) assess river hydraulic conditions using 2- or 3-D hydraulic models, (iii) develop and apply individual based models of fish population in rivers to assess the effects of river regulation.

Read more and apply for the position here, last application date is 10 January 2020.


The doctoral program consists of 240 higher education credits (4 years), including the doctoral thesis. Doctoral students may also be assigned department duties (up to 20 % of full time), such as teaching, which will extend the PhD position accordingly.


River Klarälven, Sweden

European eel, Anguilla anguilla

On Tuesday 18 June, Niclas Carlsson, lab/field technician and master student at Karlstad University, will give a seminar titled: “Low-sloping racks and the importance of bar spacing for eel passage”. The seminar starts at 13:15 in room 5F416 at Karlstad University. Everyone who wants to are welcome to attend the seminar.




Daniel Nyqvist, Jonas Elghagen, Marius Heiss and Olle Calles recently published the article “An angled rack with a bypass and a nature-like fishway pass Atlantic salmon smolts downstream at a hydropower dam” in the journal Marine and Freshwater Research.

In the abstract, the authors write:

Hydropower dams disrupt longitudinal connectivity and cause fragmentation of river systems, which has led to declines in migratory fish species. Atlantic salmon smolts rely on intact longitudinal connectivity to move downstream from rearing habitats in freshwater to feeding grounds at sea. Smolts often suffer increased mortality and delays when they encounter hydropower plants during their downstream migration. Currently, there are few examples of downstream passage solutions that allow safe and timely passage. We assessed the performance of two passage solutions at a hydropower dam, namely, an angled 15-mm rack with a bypass and a large nature-like fishway. The performance of these new fish passage solutions was evaluated by tracking radio-tagged Atlantic salmon smolts as they encountered the facilities. The radio-tagged smolts passed the dam 9.5 h after release (median) and exhibited a dam-passage efficiency of 84%, with passage rates increasing with body length. Fish passage occurred through both the rack bypass and the naturelike fishway. The passage efficiencies were 70–95% for the rack bypass and 47% for the nature-like fishway. The new fish passage facilities resulted in improved passage conditions at the site, confirming that angled racks with bypasses as best practise solutions for downstream passage, but also that large nature-like fishways may act as downstream passage routes for salmon.

Access the paper here, or contact any of the authors.

Amy Newsom on lake Alstern.

In August and September 2018, Amy Newsom from Germany visited Karlstad University and did an internship with NRRV. Here she writes about her months at Karlstad University.

“Having spent a year at Karlstad University as an exchange student in 2017 in the framework of my bachelor program “Environmental and Sustainability Studies” at the Leuphana University in Lüneburg, Germany, I had already been able to gain a first impression of the university’s biology department, which sparked my interest in freshwater ecology. Consequently, I was thrilled to have the opportunity to join the Naturresurs rinnande vatten Team for a six-week internship in August and September of 2018.

During the weeks I spent at Karlstad University, I was able to work with different researchers, getting to know a variety of projects and greatly extending my previous knowledge on freshwater and riparian ecology, in particular river connectivity. My main aim in this internship was to gain more practical research experience, so I was glad to be able to spend a lot of time both in the lab and in the field. For example, my work included processing raw data on the ventilation rates of young trout to assess differences in metabolism efficiency, counting the eggs of spiders gathered in the field and preparing samples for stable isotope analysis to assess the impact of hydro dams on food web interactions of fish. This was a particularly interesting experience as stable isotope analysis was a new scientific procedure to me, and I was keen to learn more about it. I was also excited to join in some of the field work conducted during my time at NRRV, collecting fish, invertebrates and plankton samples from the lake Alstern and electrofishing in the rivers Mörrumsån and Emån to assess the overall community composition at different sites. I was furthermore able to gain valuable insights into the design of research experiments while accompanying the setting up of an experimental flume in Älvkarleby and the preparation of eel traps in the river Alsterälven. In the time I spent in the office, I was also able to gather more experience in data analysis and scientific writing, both helpful preparations for my upcoming bachelor thesis.

Amy Newsom dissecting a crayfish.

Returning to Karlstad also gave me the opportunity to improve my Swedish, reconnect with old friends and make new contacts, as well as further explore the forests, rivers and lakes in the area that I have come to love so much. My thanks go out to John Piccolo, on whose invitation I was able join NRRV as an intern, the International Offices both in Karlstad and at my home university for helping me with the administrative process, and the German foundation Meifort Stiftung, whose generous support made this internship possible for me. I am also incredibly grateful to all the researchers at the KAU biology department who warmly welcomed me into their team, took the time to introduce me to their work and helped me gain new knowledge and experience, in particular Olle Calles, Rachel Bowes, Larry Greenberg, Denis Lafage, Karl Filipsson, Andrew Harbicht, Lovisa Lind and Niclas Carlsson.”

Amy Newsom and Andrew Harbicht (NRRV-postdoc) electrofishing in river Mörrumsån.

A cutthroat trout (Oncorhynchus clarkii).

On Monday October 8, Guillermo Giannico, Associate Professor at Oregon State University, will give a seminar titled:Fish Passage and Habitat Restoration: a Priority Setting Approach from Coastal Oregon, U.S.A”. The seminar will start at 13:30 in room 5F322 at Karlstad University. Everyone is welcome to attend the seminar.

Andrew Harbicht recently started a postdoc within the NRRV-research group at Karlstad University. Here he briefly presents his background and what he plans to do during his postdoc:

“Hello, my name is Andrew Harbicht and I’m one of the new Post-Docs to have joined the NRRV. My research experience has primarily been focused on salmonids (rainbow trout, brook charr, and Atlantic salmon) and extends from fisheries modeling to population genetics and radio telemetry. I moved to Karlstad from Montreal, Canada, where I conducted my Ph.D. at Concordia University, working together with the US Fish and Wildlife Service on Atlantic salmon restoration in Lake Champlain. During that time we investigated the impacts of hatchery rearing and release techniques on the lifetime survival and dispersal rates of landlocked salmon and investigated the impact of a thiamine deficiency on the migratory capabilities of returning spawners.

My work with this group will focus on the implications of migratory barriers for longitudinal connectivity among Atlantic salmon populations in the Baltic Sea. With the ever-increasing efficiency of new hydroelectric turbines and the costs associated with maintaining outdated installations, more and more energy producers are opting to remove older facilities to focus their efforts on newer structures. The removal of such aging dams and other barriers to migration within rivers is undoubtedly a positive step for river connectivity, though exactly what changes will occur as a result of such actions is simply unknown in many situations. In fact, over the short term, the removal of barriers can cause as many changes as initial installation. In other situations, maintaining instream infrastructure may be the best option available to energy producer. In which case, including structures that permit fish passage is important, but which type of structure is best suited to the job isn’t always clear. Where several options exist, managers need access to accurate information to assist in their decision-making process.

With my project, I’ll be looking at the impact of removing a partial barrier to migration on the movement patterns of Atlantic salmon, as well as the river ecosystem itself in the Mörrumsån river in southern Sweden. Our holistic approach will monitor all levels of the ecosystem, from the mechanisms that shape river terrain (sedimentation) to the smallest bacteria (decomposition) and the largest predators (fish), as well as all things in between (food-webs). I will also be investigating the genetic consequences of changes in movement patterns that result from the removal of a hydroelectric plant. In another river, the river Emån, we’ll be assessing the performance of a new type of fish lift, and Archimedes screw, which permits upstream and downstream passage, all the while producing its own energy. If found to be effective, such devices could greatly improve connectivity in fragmented river landscapes.”

Andrew Harbicht (left) and William Ardren (right) releasing tagged fish in the Boquet River, a  tributary to Lake Champlain.

Andrew Harbicht tracking radio tagged Atlantic salmon.


The Herting dam with the low sloping intake rack in the intake channel to the left and the large nature-like fishway to the right. (Photo from Fiskevårdstekniks film)

Recently, the paper “Upstream and downstream passage of migrating adult Atlantic salmon: Remedial measures improve passage performance at a hydropower dam” was published in the journal Ecological Engineering. The paper was authored by Daniel Nyqvist, Anders Nilsson, Ingemar Alenäs, Jonas Elghagen, Mats Hebrand, Simon Karlsson, Stefan Kläppe and Olle Calles. They summarize the paper: “Habitat connectivity is central for life-cycle progression for migrating organisms. Passage of hydropower dams is associated with mortality, delay, and migratory failure for migrating fish, and the need for remedial measures to facilitate passage is widely recognized. Lately, nature-like fishways have been promoted for upstream migrating fish, and low-sloping turbine intake racks for downstream migrating fish, but evaluations of these remedial measures are largely lacking. At Herting hydropower dam in southern Sweden, a technical fishway for upstream migrating salmonids, and a simple bypass entrance/trash gate for downstream migrating fish have been replaced by a large nature-like fishway for up and downstream migrating fish, and a low-sloping rack, guiding downstream migrating fish to the bypass entrance, has been installed. In this study, we evaluated these remedial measures for adult Atlantic salmon, spawners and kelts, in a before/after improved remedial measures radio telemetry study. Passage performance was improved for both up- and downstream migrating adult Atlantic salmon after remedial measures. Passage rate increased for fish migrating in both directions, and overall delay decreased while overall passage efficiency increased for upstream migrating fish. After the improved passage solutions almost all tagged fish passed the dam with very little delay. Before modifications, upstream passage performance through the technical fishway was higher at higher temperatures, at day compared to night, and for males compared to females. No such effects were observed for the after-measures nature-like fishway, indicating good passage performance for both sexes under a wide range of environmental conditions. Similarly, for downstream migrating kelts, discharge positively affected passage rate before but not after the fishway modifications. Altogether, our work demonstrates the possibility of coexistence between hydropower and Atlantic salmon in a regulated river.”

Access the paper here. For questions, e-mail the authors.