The book, ”Brown Trout: Biology, Ecology and Management”, edit by Javier Lobón-Cerviá and Nuria Sanz was recently published. The book is described as ”a comprehensive guide to the most current research, history, genetics and ecology of the brown trout including challenging environmental problems”. John Piccolo and Johan Watz, both researchers at Karlstad University, have written the chapter Foraging Behaviour of Brown Trout: A Model Species For Linking Individual Ecology to Population Dynamics? They summarize their chapter as follows:

”Within the discipline of stream fish ecology, population-, community-, and even ecosystem-level patterns and processes have assumed an increasingly larger role in recent decades. It might be argued, however, that research on the behaviour of individual organisms ought still to play a major role in ecology; it is upon the individual, after all, that natural selection acts. Thus, one might reasonably expect that observing an individual fish’s behaviour should lead to robust conclusions about the fitness costs and benefits that animals must trade-off in order to achieve reproductive success. And ultimately, it is those individuals that achieve the greatest direct fitness that ought to, on average, drive the population-level processes that have attracted so much of stream fish ecologists’ attention in recent years. In linking behavioral- to population-level ecology, we are in luck when it comes to the brown trout – there is no stream fish species whose population ecology is better quantified, nor are there many species that have received more attention from behavioural ecologists. Thus we might consider the brown trout as a model species for developing the ecological understanding of how natural selection (e.g. individual, fitness-based decisions) acts to regulate stream fish populations. To forward this concept, a further development of a quantitative approach to foraging behaviour is warranted. In this chapter we review and synthesize the literature on brown trout foraging experiments with an eye towards identifying the knowledge gaps that remain to be filled in order for ecologists to quantify the fitness costs and benefits of foraging behaviour.”

The book is available (but expensive) here. For access to the specific book chapter, email John Piccolo or Johan Watz.

Welcome to NRRV: Richard Durtsche

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Richard Durtsche recently joined the NRRV-research group as a visiting professor from Northern Kentucky University, USA. Here he presents his background and some of his planned work at Karlstad University:

Richard Durtsche, visiting professor at Karlstad University.

My name is Richard Durtsche, and I am a visiting professor joining the Kau River Ecology and Management Research Group from Northern Kentucky University (NKU) where I am a Professor of Biological Sciences, the Director of the NKU Research and Education Field Station, and Curator of Vertebrate Collections. I am a physiological ecologist and herpetologist with research interests in the feeding ecology, nutrition, and physiology of amphibians, reptiles, and fish along with related impacts of invasive species; niche occupancy; and bioassessment of aquatic ecosystems. I am currently on a one-year sabbatical, and my goals include professional development and exploring new research focused on modeling of fish drift-feeding and the ecophysiology of stream fishes related to my previous work on the foraging ecology and metabolism in reptiles and amphibians. This program will also strengthen the collaboration of our recently established exchange program that now exists between NKU and Kau.

My research goals are to investigate new methodologies in foraging ecology and ecological modeling as a collaborator in studies of the eco-physiology of drift feeding and energetics in Salmonid fish (trout, salmon, etc.), and potential changes in their metabolism related to thermal changes (potential effects of climate change) during development. The first part of these investigations will focus on the increased accuracy in measurements of the mass for three different macroinvertebrate (mayfly, caddisfly, and stonefly) prey types of these fish determined from digital images. These image measurements will then be combined with caloric content measures of these prey to provide an energetic basis of these food sources. The results will then be used to 1) improve theoretical models of the energetics and drift feeding by these fish for the group’s on-going studies on stream fish ecology and management, and 2) provide a basis for using digital images, potentially from a smart device, for enhanced methods and more rapid measures to understanding how different foods can influence fish distributions, their growth and abundance. The second part of this investigation will focus on the effects elevated environmental temperature (i.e., climate change) has on the metabolism of developing fish. By evaluating fish raised at different temperatures from the same cohort of eggs, we will be able to determine the plasticity (epigenetic capacity) of these northern climate fish to altered thermal environments. Measuring metabolic capacities is one of the best ways to determine the fitness of these fish and if they have the capacity to deal with climate change.”

Tomorrow, 24 October, Richard Durtsche will give a seminar titled ”Amphibians, Wetland Aquatic Ecosystems, and the Impact of Invasive Plants”. The seminar will be given at 13:15 in room 5F416 at Karlstad University.

NRRV i media

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Under sommarmånaderna har NRRV-forskares arbete eller expertis uppmärksammats i olika media. Hallandsposten skrev om passagestudier med ålyngelstudier i Laholm och intervjuade Jonas Elghagen, Lutz Eckstein intervjuades angående den invasiva lupinen i Värmlands Folkblad,och en av Anders Nilssons senaste artiklar – om hur mört-braxen-hybrider är känsligare för predation än braxen och mört –  uppmärksammades av The Economist.

A graduate student position (licentiate) in the field stream fish ecology and habitat use, is now open for applicants at Karlstad University. The position is a full time position for 2 years within the River Ecology and Management (NRRV) group at the Department of Environmental and Life Sciences. Read more about the position on


Tracking smolts in Huntington River, a tributary to Winooski River.

The accepted version of the scientific article ”Downstream migration and multiple dam passage by Atlantic salmon smolts” by Daniel Nyqvist (Kau), Stephen McCormick (USGS), Larry Greenberg (Kau), William Ardren (US Fish and Wildlife), Eva Bergman (Kau), Olle Calles (Kau), and Theodore Castro-Santos (USGS) is available online at North American Journal of Fisheries Management. The paper presents a study on downstream migration and dam passage of landlocked Atlantic salmon smolts in the River Winooski, a tributary to Lake Champlain.

In the abstract the authors write: ”The purpose of this study was to investigate behavior and survival of radio-tagged wild- and hatchery-reared landlocked Atlantic salmon smolts as they migrated past three hydropower dams equipped with fish bypass solutions in the Winooski River, Vermont, USA. Among hatchery-released smolts, those released early were more likely to initiate migration and did so after less delay than those released late. Once migration was initiated, however, the late-released hatchery smolts migrated at greater speeds. Throughout the river system hatchery released fish performed similarly to wild fish. Dam passage rates varied between the three dams and was highest at the dam where unusually high spill levels occurred throughout the study period. Of the 50 fish that did migrate downstream, only 10% managed to reach the lake. Migration success was low despite the presence of bypass solutions, underscoring the need for evaluations of remedial measures; simply constructing a fishway is not synonymous with providing fish passage.”

Access the paper here or contact the authors.

The new journal The Ecological Citizen aims to advance ecological knowledge, champion earth-centered action and promote ecocentrism in political debate. NRRV member John Piccolo recommends the journal as somewhere you’ll find much interesting reading about human relationships with nature. John is also a co-author of a recently published signable statement in support of ecocentric value that he urges our readers to read and consider signing. Access the statement here: Statement of Commitment to Ecocentrism. 

Also, related to the ecocentric debate, there is an ongoing survey of attitudes to conservation. Learn more and take the survey at

running_silver”Running Silver – Restoring Atlantic Rivers and Their Great Fish Migration” by John Waldman is a book about the history and future of anadromous fish in the Eastern United States. The books’s main characters are Atlantic salmon, alewife, blueback herring, American shad, striped bass, sea lamprey, Atlantic sturgeon, and American eel. The eel migrates from freshwater to the sea to spawn, whereas the other species typically migrate in the other direction – from feeding areas at sea to spawning areas in freshwater.

The author uses historical records, interviews, scientific literature and personal experiences to tell the story of the migrating fish. He describes the ecology and behavior of the migrating fish but also their great historical abundances, and high social and economic importance. He describes the decline of the populations of migrating fish due to dam building, habitat loss, fishing, and pollution, but also the modern day restoration efforts. The fish are put in a social context with stories about conflicts concerning dams and fish passage dating back several hundred years. Meetings with scientists and manager occur frequently in the book, contributing to the story and providing several inspiring portraits of fish ecologists.

The book is essential reading for anyone working with migrating fish and an important book for those interested in fish and our natural world. The book is a call to action for a future with healthy migrating fish populations. Read a short review here and borrow the book from a  well-stocked library.


Short film: The hyporheic zone

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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:

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.

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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