Book: Biology and Ecology of Pike

Posted by Karl Filipsson | Book

The book Biology and Ecology of Pike, edited by Christian Skov (Technical University of Denmark) and Anders Nilsson (Karlstad and Lund Universities) was recently published by CRC Press. The two editors have also authored several chapters in the book. The book is described to “emphasize the progress of pike research during the past two decades, highlight human dimension aspects in recreational fisheries, and to address environmental circumstances on pike populations including the pike individuals.” Read more about the book here.


Marcell Szabo-Meszaros, Christy Ushanth Navaratnam, Jochen Aberle, Knut Alfredsen (Norwegian University of Science and Technology), Ana T. Silva, Torbjørn Forseth (Norwegian Institute for Nature Research), Olle Calles (Karlstad University) and Hans-Petter Fjeldstad (SINTEF Energy Research) recently published the scientific paper “Experimental hydraulics on fish-friendly trash-racks: an ecological approach” in the journal Ecological Engineering. The study is part of the project SafePass, where methods for safe and efficient migration for salmonids and European eel past hydropower structures are evaluated. SafePass aims to facilitate fish migration in regulated rivers, using perspectives of both the fish and the hydropower industry. Read more about SafePass here.

In the abstract of the paper, the authors write: ”The obstruction of fish migratory routes by hydroelectric facilities is worldwide one of the major threats to freshwater fishes. During downstream migration, fish may be injured or killed on the trash-racks or in the hydropower turbines. Fish-friendly trash-racks that combine both ecological and technical requirements are a solution to mitigate fish mortality at a low operational cost. This study presents results from an experimental investigation of head-losses and the hydrodynamic performance of six angled trash-rack types with 15 mm bar spacing, varying bar-setup (vertical-streamwise, vertical-angled and horizontal bars) and bar profiles (rectangular and drop shape) under steady flow conditions. The trash-racks were positioned at 30° to the wall of the flume and combined with a bypass at their downstream end. The impact of the different trash-rack types on the upstream flow field was characterized using Image based Volumetric 3-component Velocimetry (V3V) and at the bypass-entrance using an Acoustic Doppler Velocimeter (ADV). The results show that trash-racks with vertical streamwise and horizontal oriented bars with drop-shape profiles have similar head-losses (13% difference), while trash-racks with vertical-angled bars provide 3–8 times larger head-losses compared to the remaining configurations. The velocity measurements showed that the highest flow velocities occurred for configurations with vertical-angled bars (0.67ms−1 and 0.81ms−1 on average, respectively).Turbulence related parameters (e.g. Reynolds shear stresses and Turbulent kinetic energy) were also investigated to evaluate the performance of the alternative trash-racks from both, engineering and ecological perspectives.”

Access the paper here, or e-mail any of the authors.

The Volumetric 3-component Velocimetry (V3V) system used in the study.

For the first Tuesday seminar of the year, Kristine Lund Bjørnås, PhD-student at Karlstad University, will talk about evidence synthesis in environmental science. The seminar will be held Tuesday 23 January at 13:15 in room 5F416 at Karlstad University. Everyone is welcome to attend the seminar.

In preparation for the seminar, Kristine writes:

“In these times of alternative facts and post truth, the role and authority of scientists in society is challenged. It is therefore important that we as scientists continue to improve our methods and communication – and one way of doing that is to increase interaction with the end-users of scientific findings. In environmental- and natural resource management, many important policy and practice decisions are not being taken based on the best available scientific evidence, even when that is an explicit management objective. For instance, in a questionnaire among conservation practitioners in England, the majority (77%) reported that they used “commonsense”, “personal experience” or “speaking to other managers” as their primary source of information prior to management actions (Sutherland et al. 2004). This might be because there is no clear understanding of what the best available scientific evidence (i.e. “what works”) is. As a response to this need for more evidence-based environmental management, systematic reviews have found their way also into environmental science.

Brown trout (Salmo trutta), the model species of Kristine’s dissertation project, in an aquarium at Karlstad University.

In this seminar I will go through the principles of systematic reviewing literature, the strengths and weaknesses of the method, and I will talk about my current review project.”


Sutherland, W.J.; Pullin, A.; Dolman, P.M. & Knight, T.M. 2004. The need for evidence-based conservation. TRENDS Ecol Evol. 19.6.

See also:

Mistra Council for Evidence-based Environmental management

Collaboration for Environmental Evidence

Larry Greenberg at the Lake Champlain research conference.

The Lake Champlain research conference Lake Champlain: Our future is now was held at the Davis Center, University of Vermont, in Burlington 8-9 January 2018. The conference covered a variety of topics, including climate change and native fish restoration. Larry Greenberg, professor at Karlstad University, was invited as keynote speaker at the conference and gave the talk “Conservation of landlocked Atlantic salmon in a regulated river: Taking a holistic approach.” Read more about the conference here.