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)

Although most fieldwork is carried out in warmer seasons, members of the NRRV research group also go out in winter to collect information and samples for their research. Here, Richard Durtsche, visiting professor from Northern Kentucky University, writes about a field excursion that took place last week:

Andrew Harbicht, Post-Doc at Karlstad University (front) and Richard Durtsche, visiting professor from Northern Kentucky University, (back) at the field site.

“As part of a study on the energetics in natural food sources available to Salmonid fishes (trout, salmon, grayling, etc.), we have been sampling the macroinvertebrates in streams that connect to the Klarälven (Clear River) this past fall and now this winter. These investigations will focus on an increase in the accuracy of macroinvertebrate body size measurements taken with digital imaging and an increase in the accuracy of dry mass measures using an ultramicrobalance, newly acquired by Kau Biology. Energetic (caloric) content will also be determined for the different macroinvertebrate taxa. The three target macroinvertebrates groups for this study include mayflies (Ephemeroptera), caddisflies (Trichoptera), and stoneflies (Plecoptera). These are major prey items for all life history stages of Salmonid fishes, and are often used as indicators of stream health in aquatic environmental assessment due to their sensitivity to pollutants and anthropogenic impacts. Results of this study will be useful in developing energetic models of fish foraging for management of fish population and river/stream conditions.

The team that braved the cold winter conditions and moderate snow levels on January 29th included: Richard Durtsche (NRRV visiting professor from Northern Kentucky University), Rachel Bowes (NRRV Post-Doc), Andrew Harbicht (NRRV Post-Doc), and Rachel Prokopius (exchange student from Northern Kentucky University). The stream that we were investigating was located just south of Ransäter. The water was flowing rapidly, and we initially decided to check out the stream conditions on the downhill (east) side of highway 62 to look for sampling sites. There was knee deep (or more) snow to ford before coming to forest cover where moving was easier despite many treefalls. As the streamflow was fast and the water level high, there were no safe locations to sample. So we headed west of highway 62, just off the access road. There we found good sampling habitat just downstream of a large pool that ran under a bridge on that road.

Rachel Prokopius, exchange student from Northern Kentucky University, and Richard Durtsche, measuring the stream width and flow rates.

One of the first things we did at waterside, was to collect physicochemical measures of the water conditions. These included: temperature, pH, conductivity, and dissolved oxygen. We also measured the flow volume of water by measuring the width of the stream, and then taking the depth and flow rates every 50 cm across the stream. Water temps of 1.4°C and the tingle of cold penetrating our waders told us that today was not a good day to fall in the water. After we crossed the fast-flowing stream, we found several relatively shallow areas where we could sample invertebrates. We made a series of kick seine samples from different parts of the stream shallows to dislodge and collect invertebrates from the stones and substrate. 

It was definitely a group effort to kick stones and stream bottom, brush rocks to knock off invertebrates to be carried with stream flow into the seine, and then wash the samples into a collecting bucket. While we thought we might have limited luck, we in fact did extremely well with collecting a range of macroinvertebrates and large quantities of many of those taxa. There will be a good share of macroinvertebrate sorting and measuring upon return to the laboratory.”

Rachel Prokopius, Rachel Bowes, Post-Doc at Karlstad University, and Andrew Harbicht sampling invertebrates using a kick seine.


The team at work in the stream.


Richard Durtsche at the field site.


Close-up photo of a stonefly (Plecoptera) larva.


Tomorrow, 26 September, Rachel Bowes, postdoctoral researcher at Karlstad University, will give a seminar on “Temporally analyzing river food webs”. The seminar will be given at 13:15 in room 5F416 at Karlstad University. Everyone is welcome to attend the seminar.

Rachel Bowes has recently joined the NRRV-research group. Here she writes about her previous work and what she intends to do as a postdoc at Karlstad University:


Rachel Bowes (right) with Brendan Martin, sampling algae.

“Hello! I’m Rachel Bowes and I am so excited to be joining NRRV! I just wanted to take a moment and tell you a little about me and my previous research. I have always had a deep appreciation and fascination for the natural world, and this has developed over the years into an insatiable desire to learn everything I possibly can about it. Not only do I want to discover, but I want to share these findings with everyone, and protect the Earth that I care about so much.

I completed my doctorate in May 2016 from the Department of Ecology and Evolutionary Biology at the University of Kansas (KU). My dissertation was entitled: Temporal Analysis of River Food Webs. Rivers and their tributaries are the arteries of the planet, pumping freshwater to wetlands and lakes and out to sea. Understanding energy flow up trophic levels, nutrient cycling pathways, and relative importance of terrestrial and aquatic carbon sources supporting aquatic consumers in large river food webs is essential in planning for wildlife conservation, environmental protection, and floodplain management. The principal goal of my dissertation was to understand better the factors controlling the complexity of river food webs through time.


Rachel Bowes (right) with Holly Lafferty, seining for fish in the Kansas River.

At a shorter time scale, I first looked at how season and food availability affect fish in rivers. I employed bulk tissue stable isotope analysis to determine trophic position of fish in the field, over different seasons, and fish in the lab, under different amounts of nutrient stress.

In the remaining chapters of my dissertation, I utilized a new technique, applying nitrogen and carbon stable isotope analysis of amino acids to samples to determine trophic position and carbon food sources over time.  First, I demonstrated the utility these new methods in a controlled feeding experiment in the laboratory, determining fish trophic positions. I showed that the new methods seemed to offer more accuracy and precision in trophic position estimates when compared to more traditional methods of bulk tissue isotope analysis. With these new analytical methods, I proposed multidimensional metrics for use with compound specific analyses of food webs, as well as other multidimensional community measures (e.g., fatty acids, ordinal traits). Then, I evaluated long-term historical changes in trophic position and food sources of fish museum specimens using amino acid stable isotope analyses of both the Mississippi and Ohio rivers.


Rachel Bowes (right) in the laboratory at University of Kansas.

Rivers are among the most extensively altered ecosystems on earth. Over 60% of the world’s large river basins are now affected by dams for irrigation, urban development, navigation, and energy production. Many countries are recognizing the negative implications of these impoundments and are now actively removing dams. For my post-doc research here at Karlstad, I will be using my expertise in stable isotopes to look at river connectivity and the implications of dam removal on river ecosystems. There are several potential facets that we will be looking at, including fish movement, population genetics, and transfer of nutrients from marine to freshwater to terrestrial ecosystems. Stay tuned for more developments coming soon!

If you want to follow my current research and its progress, learn more about specific projects I have been involved in previously, or read about my diverse teaching experiences, please visit my website: rebowesecology.com. You can also follow me on Twitter @EcologyRachel.”