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

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.