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.

Andrew Harbicht recently started a postdoc within the NRRV-research group at Karlstad University. Here he briefly presents his background and what he plans to do during his postdoc:

“Hello, my name is Andrew Harbicht and I’m one of the new Post-Docs to have joined the NRRV. My research experience has primarily been focused on salmonids (rainbow trout, brook charr, and Atlantic salmon) and extends from fisheries modeling to population genetics and radio telemetry. I moved to Karlstad from Montreal, Canada, where I conducted my Ph.D. at Concordia University, working together with the US Fish and Wildlife Service on Atlantic salmon restoration in Lake Champlain. During that time we investigated the impacts of hatchery rearing and release techniques on the lifetime survival and dispersal rates of landlocked salmon and investigated the impact of a thiamine deficiency on the migratory capabilities of returning spawners.

My work with this group will focus on the implications of migratory barriers for longitudinal connectivity among Atlantic salmon populations in the Baltic Sea. With the ever-increasing efficiency of new hydroelectric turbines and the costs associated with maintaining outdated installations, more and more energy producers are opting to remove older facilities to focus their efforts on newer structures. The removal of such aging dams and other barriers to migration within rivers is undoubtedly a positive step for river connectivity, though exactly what changes will occur as a result of such actions is simply unknown in many situations. In fact, over the short term, the removal of barriers can cause as many changes as initial installation. In other situations, maintaining instream infrastructure may be the best option available to energy producer. In which case, including structures that permit fish passage is important, but which type of structure is best suited to the job isn’t always clear. Where several options exist, managers need access to accurate information to assist in their decision-making process.

With my project, I’ll be looking at the impact of removing a partial barrier to migration on the movement patterns of Atlantic salmon, as well as the river ecosystem itself in the Mörrumsån river in southern Sweden. Our holistic approach will monitor all levels of the ecosystem, from the mechanisms that shape river terrain (sedimentation) to the smallest bacteria (decomposition) and the largest predators (fish), as well as all things in between (food-webs). I will also be investigating the genetic consequences of changes in movement patterns that result from the removal of a hydroelectric plant. In another river, the river Emån, we’ll be assessing the performance of a new type of fish lift, and Archimedes screw, which permits upstream and downstream passage, all the while producing its own energy. If found to be effective, such devices could greatly improve connectivity in fragmented river landscapes.”

Andrew Harbicht (left) and William Ardren (right) releasing tagged fish in the Boquet River, a  tributary to Lake Champlain.

Andrew Harbicht tracking radio tagged Atlantic salmon.

“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.

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!

Last Friday, I, Daniel Nyqvist, successfully defended my PhD-thesis “Atlantic salmon in regulated rivers – Migration, dam passage, and fish behavior” at Karlstad University. Scott Hinch (University of British Columbia, Canada) was opponent and Eva Thorstad (NINA, Norway), Kim Aarestrup (DTU AQUA, Denmark) and Hans Lundqvist (Swedish University of Agriculture) constituted the grading committee (betygskommitté). The short abstract of the thesis reads:

“Hydropower dams block migration routes, thereby posing a threat to migratory fish species. Fishways and other fish passage solutions may aid fish to pass hydropower dams. A functional fish passage solution, however, must ensure safe and timely passage for a substantial portion of the migrating fish. In this thesis, I focus on downstream passage and evaluate the behavior and survival of migrating Atlantic salmon in relation to dams in systems with (1) no fish passage solutions (2) simple passage solutions (3) best available passage solutions. In addition, I studied the survival and behavior of post-spawners and hatchery-released smolts.

A large portion of the spawners survived spawning and initiated downstream migration. For hatchery-reared smolts, early release was associated with faster initiation of migration and higher survival compared to late release. Multiple dam passage resulted in high mortality, and high spill levels were linked to high survival and short delay for downstream migrating salmon. For smolts, dam passage, even with simple passage solutions, was associated with substantial delay and mortality. Rapid passage of a large portion of the migrating adult salmon was achieved using best available passage solutions.”

The frame of the thesis is available here. Already published papers included in the thesis are Post-Spawning Survival and Downstream Passage of Landlocked Atlantic Salmon (Salmo salar) in a Regulated River: Is There Potential for Repeat Spawning? (in River Research and Applications) and Migratory delay leads to reduced passage success of Atlantic salmon smolts at a hydroelectric dam (in Ecology of Freshwater Fish). For full access to the thesis, contact daniel.nyqvist@kau.se.

The short film “La Vida se Mueve” (en. “Life is motion”) discusses fish migration, dam passage, and river restoration i Spain. It is available online (with subtitles) here:

The film is produced for the River Duero Basin Authority Read. Read more about the theme at www.cipríber.eu.

A few weeks ago Stina Gustavsson and I (both PhD-students at KaU) attended a course in “Fish migration: Theory and technology” at the Tromsö University (UiT). The course was given by Eva Thorstad (NINA and UiT) and Audun Rikardsen (UiT). Topics included ecology and evolution of fish migration, methods in fish telemetry (tags and tagging) and plenty of case studies on migrating fish. Focus was on anadromous salmonids in northern Europe – Atlantic salmon, brown trout and arctic charr – and European eel, but (for example) fish migration studies in the Zambezi River and on Atlantic halibut were also discussed. Elina Halttunen, IMR also visited the course and gave a lecture on the importance of Atlantic salmon post-spawners and their downstream migration. Other attendees included Master- and PhD-students from Tromsö University (Norway), Oslo University (Norway) and DTU Aqua (Denmark). It was an interesting course with good lectures and a lot of stimulating discussions.

“Arctic charr in midnight sun”
Photo: Audun Richardsen – www.audunrikardsen.com

Last week I visited Murcia and a fish migration project in the Segura River. The Segura River is one of Europe’s most regulated rivers with a multitude of dams and water abstractions (for agriculture in hot but dry conditions) as well as interbasin transfer of water. It also receives a heavy nutrient load and many exotic species have invaded its waters. During later years, water quality has improved and, as part of the LIFE project Segura Riverlink, improving longitudinal connectivity for local fish species is now on the agenda. Several fishways have been or will be constructed, both vertical slot fishways and naturelike fishways, and at least one migration obstacle has been permanently removed. The target species for the efforts is the Andalusian barbel (Luciobarbus sclateri), a fish that typically migrates within the river system. Read more about the project in this LIFE-folder.

Andalusian barbel (Luciobarbus sclateri)

A newly constructed naturelike fishway in the Segura River.

A vertical slot fishway in the Segura River.

Fishway, migration obstacle, river and dry surroundings.

The scientific article “Downstream migration of the European eel (Anguilla anguilla) in the Elbe River, Germany: movement patterns and the potential impact of environmental factors” has been published in River Research and Applications. Authors are Florian Stein, Peer Doering-Arjes, Erik Fladung, Uwe Brämick, Barry Bendall and Boris Schröder. In the article’s abstract they write:

“Recruitment of European eels (Anguilla anguilla) has declined to the extent that they have been added to the IUCN Red List of Threatened Species. Therefore, it is critical to ensure that eels complete their outward river migration in order to contribute to the available spawning stock. We conducted a four-year (2007-2011) telemetry study to understand the migratory behaviour and potential impact of environmental factors on the eel during this critical life stage.
Out of 399 female eels tagged with acoustic transmitters, only 28 % demonstrated clear downstream migratory behaviour. Fifty-five percent were detected exhibiting no downstream migration behaviour and 17 % were not detected at any monitoring station. Movement patterns of downstream-migrating (silver) eels were characterised by nocturnal activity and seasonal migration, with distinct peaks in autumn and spring. Migration was often discontinuous and exhibited phases of active locomotion and expanded stopovers. The most important determinants of movement activity were water temperature, cumulative precipitation, and moonlight, although the significance varied by season and location in the river basin.
Our results evidence a discontinuous, stepwise migration over an extended period. Furthermore, our findings indicate that migration success depends on holding duration prior to tagging, and environmental predictors with varying importance depending on the season, as well as the locations of capture, tagging and release.”

If you don’t have access to the article (DOI: 10.1002/rra.2881), get in touch with the authors.

Olle Calles rapporterar från Fiskmarknaden i  Nederländerna:

“Last week Vismarkt 2013 was organized December 11-12 in Tiel, the Netherlands. This is the third conference on this format, after the Vismarkt 2012 in Netherlands and Fiskmarknad 2013 in Karlstad, Sweden. The theme was again fish migration, rehabilitation and techniques to trap, tag and track fish. The two-day event included one day of field-trip and one day of presentations and exhibition. Participants presented a large number of ongoing activities in the Netherlands, Belgium and Germany. The exhibiting companies presented their products during 3 min pitch presentations. I presented the Swedish perspective and our experience in a key-note presentation. I also took the opportunity to advertise our Master course in Stream ecology, which resulted in several interested students from Netherlands, Belgium and Spain.”