Summertime field work in the Scandinavian mountains

Summertime field work in the Scandinavian mountains

By Phoenix Rogers

The opportunity LOREX provided to spend the summer in Sweden working in a brand-new environment with a team of collaborators was an incredible experience. A big thanks goes out to everyone who helped make this trip possible. Now that I’ve returned from Sweden, I would like to share some stories about the challenges our team and I faced during my 19 days in the field this summer and also elaborate on the research project that I took on while working there.

The Stekenjokk field team pictured from left to right: Karl Heuchel, Shun Koizumi, Fredrik Sundber, Pär Byström, and Phoenix Rogers. (Photo credit: Phoenix Rogers)

Umea, Sweden is 30 degrees north from my home institution in Tuscaloosa, Alabama, resulting in a drastically different climate from what I’ve become accustomed to. During the summer, Sweden is relatively dry and cold, but there are some days that can get surprisingly hot. This can be exacerbated by the long summer days in northern Sweden when the relief of night never seems to come. Even after a tough day in the field, it was difficult to fall asleep at a reasonable time since at midnight it could still be light outside (example in image below). Sleeping in was almost impossible too since the sun rises so early in the morning that the field tent quickly became a sauna. On the flip side, the long summer days aren’t all that bad since you don’t have to worry about your workday getting cut short due to nightfall and the accompanying darkness. Plus, it almost always made it possible to do a little fishing after work! Pro tip: don’t forget a blindfold before making plans to visit a place like Sweden in the summer and give your body time to adapt to the long summer days.

This picture was captured around midnight of our first sampling trip, so even this late in the day there is still plenty of light available to do some post-work fly fishing. (photo credit Shun Koizumi)

Our research group was primarily interested in brown trout population dynamics in pristine systems, which brought us to the remote mountains near Stekenjokk, Sweden for our field work. This mountainous region is primarily undeveloped, so we had to reach our field sites by helicopter. Don’t get me wrong, the aerial views from the helicopter rides were unforgettable but relying on a helicopter for transportation had some challenges. We needed to bring sampling gear and enough food and supplies to last 5 people for up to two weeks, resulting in a huge mess of things that we needed to transport in a helicopter. This forced us to be very considerate about what we decided to bring since it wasn’t possible to bring everything we might need nor was it easy for items to get brought to us once we were out in the field. We learned this lesson the hard way when we had pieces of equipment fail, requiring replacement parts flown in – this not only gets expensive but also slows down productivity and extending our stay in the mountains. Long story short: using a helicopter to move between field sites can be so fun, but it does add a new, challenging element to the logistics.

Brown trout were the focal species of our study, so we spent a lot of our time and energy attempting to sample them using gill nets and electrofishing. Pär Byström is shown bringing in a gill net full of brown trout from one of our study lakes. (photo credit Shun Koizumi)

We pushed the weight and space limits of our helicopters to the limit with all of our gear and personal. It took time to pack our gear in a way that it could easily be transported by the helicopter, but was well worth the effort since the alternative was carrying it through the mountains on foot. (Photo credit: Phoenix Rogers)

The midnight sun and helicopter rides were unique experiences, but the real reason I flew halfway across the world to Sweden was for a research project I had spent months developing and tweaking. The big-picture question I was trying to answer was: does the input of drifting invertebrates entering lakes support lake-dwelling brown trout? To address this question, I deployed drift nets for 24 hours at the end of stream inlets, right before they entered the lake. I also collected kicknet samples from the same streams so I could compare drift rates between streams. The inlets containing brown were also electrofished and a sub-sample of those fish were kept for gut content analysis. Gill nets were also deployed in the lakes and the guts will be analyzed by all fish captured. Inspiration for this study came from some work done by Jack Dendy in 1939, who investigated the fate of invertebrates drifting into lakes. Dendy’s results did not show support for drifting invertebrates being an important flux of energy for lake-living fish, but his work was limited to a single lake inlet in Michigan and his sampling efforts didn’t include fish diets. Our approach expands on Dendy’s initial study by attempting to identify if the flux of invertebrates entering lakes supports lake-living brown trout, which could change our understanding of food web dynamics in lakes.

I deployed dozens of drift nets in the inlets around our study lakes to measure if the flux of invertebrates drifting into these systems supports lake-living brown trout. Many of my samples still need to be processed before we make any conclusions about this statement. (photo credit Pär Byström)

A summer in Sweden sounds like loads of fun (and it really was) but I also went there with a job to do. Some of our data has been processed, but there is still a lot of work to be done, including another summer of sampling. I’m excited to continue working with my collaborators in Sweden to increase our understanding of brown trout population dynamics and the role of invertebrate drift in supporting lake-living brown trout. To keep up with how this project progresses, check out my research website ( or follow me on twitter (@phoenix_rogers).

One of the many brown trout we caught during our tour in the field. I wish I could say I caught this on my fly rod, but this was one of the brown trout we pulled out in our gill nets! (photo credit Shun Koizumi)

The summer sunsets in Stekenjokk took place late in the day and seemed to last hours, leaving us with an incredible view of the area. (photo credit: Phoenix Rogers)

On sunny days like this it was tempting to jump in the study lakes to cool down, but the frigid water was quick to cool you down if you did. (photo credit: Karl Heuchel)

This tentipi served as our home while we conducted our fieldwork. Four of us could fit in here very comfortably and it became a safe haven when we needed an escape from the mosquitos. (photo credit: Phoenix Rogers)

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