Short film: The hyporheic zone

Posted by Daniel Nyqvist | Nyheter

The hyporheic zone –  the region beneath the river bottom – is home to a wide range of minute life forms and processes of high importance for the ecology of the river. Learn more in the short film Secret Life of Rivers:


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fishway for upstream migrating salmonids, and a simple bypass entrance/trash gate for downstream migrating fish have been replaced by a large nature-like fishway for up and downstream migrating fish, and a low-sloping rack, guiding downstream migrating fish to the bypass entrance, has been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.

John Piccolo, researcher at Karlstad University, recently published an article in Journal for Conservation of Nature about value in natureThe paper is titledIntrinsic values in nature: Objective good or simply half of an unhelpful dichotomy?”. In the abstract John Piccolo writes: ”Two generations of conservationists and philosophers have built a strong case for intrinsic values in nature; they are the basis of the normative postulates of conservation biology. I argue that the recognition of intrinsic natural value is a fundamental and non-negotiable aspect of an eco-evolutionary worldview. Recently, relational values, “preferences, principles, and virtues associated with relationships”, have been proposed as a third category of values in nature, which may help to resolve the debate between instrumental and intrinsic valuation. By depicting intrinsic values as part of an unhelpful dichotomy between anthropocentric and ecocentric values, the current assessment of relational values fails to adequately account for the modern philosophical view of intrinsic natural value. The recognition of intrinsic natural value is not merely an academic exercise, but rather a vital aspect of conservation of the biosphere; recognition of value entails the obligation to do what is right, i.e., protect the good. Any attempt to reframe the discussion about values and environmental protection through more formal recognition of relational values will need to more clearly address how relational and intrinsic values coexist and how they can jointly form the basis for nature conservation.” 

Read the full paper here.

Tomorrow (Tuesday), February 28, David Aldvén from the University of Gothenburg and Vattenfall AB, will give a seminar titled ”Downstream migration of anadromous brown trout”. David Aldvén finished his PhD with a thesis titled ”Migration in anadromous brown trout”. The frame of his thesis is available online here.

The seminar will be given at 13:30 in room 5F416 on Karlstad University. Everyone is welcome to attend!


Caryn Vaughn (left) asking questions to Lea Schneider (right) during the PhD-defense.

Today Lea Schneider successfully defended her PhD-thesis ”Conservation ecology of the thick-shelled river mussel Unio crassus – the importance of parasite-host interactions” at Karlstad UniversityCaryn Vaughn (University of Oklahoma, USA) was the opponent, and Leonard Sandin (Swedish University of Agriculture), Niklas Janz (Stockholm University, Sweden), and Annie Jonsson (University of Skövde, Sweden) constituted the grading committee (betygskommitté).

Lea Schneiders supervisors during her PhD were Martin Österling and Anders Nilsson from Karlstad University, and Johan Höjesjö from the University of Gothenburg, Sweden. Her work constituted on part of the LIFE-project UCforLife – Målarmusslans återkomst.

The thesis is available here. Contact Lea Schneider for questions and additional information.

The study focused on the behavior of kelts at the Edsforsen dam – the first dam that the downstream migrating kelts encounter.

The scientific paper ”Intake Approach and Dam Passage by Downstream-migrating Atlantic Salmon Kelts” by Daniel Nyqvist, Eva Bergman, Olle Calles, and Larry Greenberg was recently published in River Research and Applications. The paper presents a study on the behavior of downstream migrating kelts in the River Klarälven, Sweden. In the abstract the authors write:

”Studying fish behaviour at hydropower dams is needed to facilitate the design and improvement of fish passage solutions, but few studies have focused on Atlantic salmon kelts. Here, we used radio telemetry (n = 40, size range = 50–81 cm) and acoustic sonar to study kelt movements in the forebay as well as their dam passage survival and subsequent migration success past multiple dams. We also compare radio telemetry and acoustic sonar observations of fish behaviour and used acoustic sonar to measure the depth distribution of fish approaching the turbine intake zone. Passage success at the dam was 41%, and mortality was largely associated with turbine passage (62%). The two fish that passed via the spill gates survived and continued their downstream migration. At the dam, all but one radio-tagged kelt approached the intake zone shortly after arrival to the forebay, and sonar data showed that approaching fish were predominantly surface oriented (72%, 88% and 96% of the observations were less than 1, 2 and 3 m deep, respectively). Turbine passage rate from the intake zone was higher at night than at day, indicating that the lack of visual cues may reduce the barrier effect of the 70-mm conventional trash rack. Turbine passage rate also increased with increasing hydropower generation. The percentage of observed upstream movements away from the intake zone compared with the total number of observations was considerably greater in the radio telemetry data (41%) than in the sonar data (4%). Only one fish survived passage of all eight hydropower dams to reach the lake. This low-passage survival underscores the need for remedial measures to increase the survival of migrating kelts, and the fish’s surface orientation as well as their rapid approach to the intake rack should be taken into account when designing such measures.”

Read the paper here. If you don’t have access to the journal’s content, email any of the authors.

Fish Passage 2017 – International Conference on Engineering and Ecohydrology for Fish Passage will be held in Corvallis, Oregon, USA on June 19-21 2017. The confererence ”…promises to be an important international forum for researchers and practitioners to exchange findings and experiences on fish passage issues.

Fish Passage 2017 will be of interest to researchers, educators, practitioners, funders, and regulators who have an interest in advancements in technical fishways, nature-like fishways, stream restoration and stabilization, dam removal, and the myriad of funding, safety, climate change, and other socio-economic related issues surrounding connectivity projects.

This is a three-day conference with concurrent sessions in engineering, biology, management and monitoring techniques. The conference will also feature plenary talks, professional networking opportunities, and a poster session. Independently offered short courses, workshops and tours will be available immediately before and/or after the conference.”

Plenary speakers will be say’ay’ – John Eli Sirois, Futoshi Nakamura, Tony Farrell, Paul T. Jacobson, and Kurt D. Fausch. Read more about the plenary speakers here. Also, pre-conference short courses and post-conference tours are available. Read more about the conference at




John Piccolo recommends the short film ”Lahontan Cutthroat Trout: A prehistoric legend returns”. The film briefly discusses the restoration of cutthroat trout to Pyramid Lake and the Truckee River in Nevada, USA. This strain of cutthroat trout was assumed extinct until remnants of the population were found in streams in neighboring Pilot Peaks. This started great efforts to re-introduce the socially and culturally important fish population to the lake. Watch the film here:

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According to tradition, Lea Schneider (center) last week nailed her thesis to the wall, at the entrance to Karlstad University. On the photo are also Martin Österling (supervisor) and Reine Lundin (dean).

On February 24, Lea Schneider, will defend her PhD-thesis ”Conservation ecology of the thick-shelled river mussel Unio crassus – the importance of parasite-host interactions”. In the abstract Lea Schneider writes: ”Unionoid mussels are globally threatened and their conservation requires species-specific knowledge on their ecology and parasite-host interaction. Unio crassus is one of Europe’s most threatened unionoid species and has a temporary obligate parasitic life stage (glochidia) on fish. A lack of suitable hosts is probably a major limitation for mussel recruitment, but host species composition, suitability and availability in time and space have yet to be fully explored. This thesis examines different aspects of the host fish species, including their composition, suitability and ecological importance, in relation to U. crassus, using both field and laboratory studies. The effects of mussel and host density on mussel reproductive potential were considered, as were aspects of evolutionary adaptations between mussels and fish and how climate change may affect their interaction.

The results show that U. crassus is a host generalist, parasitizing a variety of fish species. Host suitability and density, which varied among fish species and rivers, affected the level of glochidia encapsulation, hence mussel reproductive potential, more so than the density of mussels taking part in reproduction. Ecologically important hosts included both highly suitable primary hosts, and less suitable hosts that were highly abundant. Whether or not U. crassus has specific adaptations to its hosts to enhance juvenile transformation remains unclear. No distinct pattern of local adaptation was found, nor was there an effect of host fish presence on the timing of glochidia release by adult mussels. Instead, temperature played a major role, with results suggesting that changes in spring water temperature regimes can cause temporal and spatial mismatches in the mussel-host interaction. This thesis indicates that investigations of local mussel-host interactions help in identifying mechanisms important for unionoid conservation management and prioritization.”

The defense will take place on February 24 at 10:15 in room 1B309 (Sjöströmsalen) at Karlstad University. The frame of the thesis is available online here.

For the defense, Caryn Vaughn (University of Oklahoma, USA) is the opponent, and Leonard Sandin (Swedish University of Agriculture), Niklas Janz (Stockholm University, Sweden), and Annie Jonsson (University of Skövde, Sweden) constitute the grading committee (betygskommitté).

In the afternoon (from 13:30 onwards) the day before the defense (Feb 23), seminars related to the thesis will be given in Room 5F416 at Karlstad University. Here Caryn Vaughn will present on ”Consumer aggregations act as hotspots of ecosystem function and services in rivers”, Niklas Janz on “What is host range?”, and Leonard Sandin on “Evaluation of ecological restoration in Swedish streams – some results from the EKOLIV project”. 

Everyone is welcome to attend both the PhD-defense and the seminars.

Johan Watz, postdoc vid Karlstads Universitet, forskar om öringens vinterekologi. Just nu pågår fältarbete i Rottnan, Värmland. Johan berättar: ”Vinterförhållanden i rinnande vatten kan påverka hur mycket fisk som kan leva i älven och hur många smolt som produceras. I ett projekt tillsammans med Fortum och Bergvik Skog undersöker vi hur öringungar klarar vintern i sidofåror till Rottnan. Platser som har berikats med struktur, i form av träd som fällts i vattnet, jämförs med platser utan trädberikning. Ettåriga PIT-märkta öringar spåras genom isen, och med stationära loggerstationer. Öringarnas förflyttningar, överlevnad och tillväxt studeras. Projektet kommer fortgå fram till islossningen.”


Johan Watz, mitt i Rottnan. ”Fältarbete i -20C kan vara så här roligt.”


Lisse de Groot, Erasmuspraktikant från Nederländerna, vid en damm av bottenis.


En loggerstation (vid den svarta plastpåsen) detekterar fiskar som simmar förbi.


Teemu Collin och Niclas Carlsson (studenter vid Karlstads Universitet) pejlar öring.

Verkar detta intressant? Just nu söker Karlstads Universitet en doktorand i just fiskars vinterekologi: PhD position in Global climate change and winter ecology