A spawning male sockeye salmon (Oncorhynchus nerka)

During the 50th anniversary meeting of the Fisheries Society of the British Isles at the University of Exeter in July 2017, the participants held a workshop to develop a publication titled “Valuing and understanding fish populations in the Anthropocene: key questions to address”, for the special issue of the Journal of Fish Biology.

John Piccolo from Karlstad University contributed to this paper, focusing on a current research theme on conservation ethics. The paper is now published. Access the paper here, or contact any of the authors. John has also promised a coming NRRV post highlighting some recent work in this area.

In the abstract of the paper, the authors write:

“Research on the values of fish populations and fisheries has primarily focused on bio-economic aspects; a more nuanced and multidimensional perspective is mostly neglected. Although a range of social aspects is increasingly being considered in fisheries research, there is still no clear understanding as to how to include these additional values within management policies nor is there a cogent appreciation of the major knowledge gaps that should be tackled by future research.
This paper results from a workshop held during the 50th anniversary symposium of the Fisheries Society of the British Isles at the University of Exeter, UK, in July 2017. Here, we aim to highlight the current knowledge gaps on the values of fish populations and fisheries thus directing future research. To this end, we present eight questions that are deeply relevant to understanding the values of fish populations and fisheries. These can be applied to all habitats and fisheries, including freshwater, estuarine and marine.”

Johan Watz, Anders Nilsson and Olle Calles from Karlstads Universitet, and Jonas Elghagen from Elghagen FIskevård, recently published the scientific note “Evaluation of a novel mobile floating trap for collecting migrating juvenile eels, Anguilla anguilla, in rivers” in the journal Fisheries Management and Ecology.

In the abstract, the authors write: “To improve the situation for the threatened European eel in regulated rivers, better methods need to be developed that more efficiently collect and transport juvenile eels past dams. In this study, a novel mobile, floating eel trap is described, and the results from an evaluation of the trap in two Swedish regulated rivers are presented. The mobile trap was designed to reduce the length of the climbing distance while maximizing the width of the entrance. The mobile trap caught more juvenile eels than a stationary eel ladder, serving as control. Furthermore, the mobility of the floating trap enables adaptive placement and thus offers managers the possibility to search for the spatial optimum for trapping efficiency.” Access the paper here, or e-mail any of the authors

The mobile floating trap next to the stationary eel ladder used as control. Photo from the Watz et al. 2017.

The mobile floating trap without cover. Juvenile eels climb the short and wide ramps (black) and slide (on the small metallic shutes) towards the left (in the photo) were they are collected. Photo: from the papers supplementary material.

The trap in the tailrace of a hydropower plant in River Lagan.

A sample of juvenile eels caught in the study, here held in a 10 L bucket.

I Klarälven samexisterar bland annat fisk, sportfiske, turism, vattenkraft och frilufsliv i ett område med skogsbruk, industri och jordbruk.

Beatrice Hedelin, forskare med samhällsvetenskaplig inriktning inom NRRV, publicerade nyligen en artikel med titeln “Participatory modelling for sustainable development: Key issues derived from five cases of natural resource and disaster risk management”. Artikeln presenterar en studie av Participatory Modelling. Det handlar om  ett modell-verktyg som kan användas som stöd för att driva en besluts/planeringsprocess som involverar de som är berörda. För att dels få kunskap om systemet, men även göra beslutsprocessen mer transparent, demokratisk och inkluderande. Det handlar alltså inte bara om att få kunskap om systemet utan om hur modeller kan användas för att bidra till  besluts-/planeringsprocesser. I ett rinnande vatten perspektiv kan till exempel geohydrologiska data (grundvattennivåer, nederbörd, flöden, uttag av vatten, avrinning), biologiska data (förekomst av nyckelarter, siktdjup, pH), ekonomiska data (kostnad för vattenuttag, kostnad för gödsel, inkomster från turismnäring) modelleras tillsammans med information om, och aktivt deltagande från, deltagare såsom allmänhet, kommuner, länsstyrelse, sportfiskeföreningar, lantbrukare/LRF, fastighetsägare, nationella myndigheter, turistförening.

Beatrice Hedelin beskriver själv artikeln: “Artikeln presenterar en studie där jag och kollegor från Linköpings universitet (Anna Jonsson, numera SMHI), Lunds universitet (Johanna Alkan-Olsson) och Bonn universitet (Mariele Evers) studerar fem fall av s k participatory modelling (deltagande modellering). Participatory modelling (PM) är ett underfält till både participatory planning och environmnetal modelling, där man utvecklar och tillämpar verktyg för att stödja deltagande i planering och förvaltning av naturresurser. Modeller av socio-ekologiska system, som exempelvis ett älvsystem eller ett marint reservat, är centrala delar i verktygen. Modellverktygen är ofta datorbaserade och kan vara av olika sorter, från avancerade matematiska simuleringsmodeller av socio-ekologiska system som kräver mycket data, till verktyg som bygger på en mer förenklad modell av systemen och på olika gruppers förståelse av hur systemen fungerar, exempelvis vilka konsekvenser ett visst uttag av fisk skulle få.

De fem fall som analyseras i studien är alla relativt omfattande forskningsprojekt i Sverige, EU och Indien som rör PM inom naturresurs- och naturriskhantering. Genom att analysera de medverkande forskarnas kunskaper och erfarenheter från fallen bidrar studien till att identifiera kritiska frågor för fortsatt forskning inom PM. Studien indikerar att det finns en stor potential inom PM att stödja kunskapsintegrering och lärande hos de som är involverade i processerna, om de socio-ekologiska systemen som studeras och om förståelser av dem. Dessutom stödjer de studerade fallen transparens i beslutsprocesserna. De studerade fallen indikerar vidare att det finns ett stort behov av forskning och utveckling vad gäller PM:s förmåga att stödja helhetssyn m a p organisering, exempelvis genom att skapa strukturer för organisatoriskt lärande eller för att koppla samman PM-processen med dess politiska och organisatoriska sammanhang. Dessa frågor är tätt kopplade till möjligheten att implementera PM i praktiken.”

Läs abstrakt till artiklen här. Saknar du tillgång till tidskriftens innehåll, kontakt någon av författarna.

uniocrassus

Adult thick shelled river mussel (Unio crassus) from the River Tommarpsån, Sweden.

Lea Schneider, Anders Nilsson, and Martin Österling from Karlstad University, recently published the scientific article “Evaluating temperature- and host-dependent reproduction in the parasitic freshwater mussel Unio crassus” in the journal Hydrobiologia. In the article they present a study on the thick shelled river mussel (Unio crassus) and its release of glochidia (mussel larvae) in different temperature regimes.

In the abstract they write: “Adaptation to temperature regimes and host presence may enhance fitness in parasites. In an experimental study, we evaluated the timing of glochidia release by Unio crassus subjected to three spring water temperature regimes in the presence and absence of the host fish Cottus gobio. The timing of glochidia release was delayed at (i) constantly low temperatures (<10°C), in contrast to earlier and pronounced releases at (ii) natural temperature increases that level off at intermediate temperatures (10–15°C), and (iii) higher-than-normal temperatures (10–20°C). Mussels from treatment (i) that had not released glochidia during the experiment did so soon after being moved to the temperature in (ii), indicating a temperature threshold for glochidia release. Neither host fish presence nor the combined effect of temperature and host fish presence significantly affected the timing of glochidia release. The treatment with natural spring water temperatures indicated possible fitness benefits for U. crassus through combined effects of high intensities of glochidia releases and high survival of released glochidia. The furthered understanding of climate change effects on mussel and host phenology in seasonal environments, potentially inducing temporal mismatches of glochidia release to host availability, is key to mussel conservation.”

Acces the paper here: Evaluating temperature- and host-dependent reproduction in the parasitic freshwater mussel Unio crassus

The research was part of the LIFE project UCforLIFE. Read more about the thick shelled river mussel and related conservation work at the projects homepage: www.ucforlife.se

Herting

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.

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.

oecologia

Johan Watz contributed the cover photo.

The paperIce cover affects the growth of a stream-dwelling fish”  by Johan Watz, Eva Bergman, John Piccolo and Larry Greenberg was published as the cover article in the May issue of the scientific journal Oecologia. The journal presents its issue and the paper:

“Winter conditions are believed to play an important role in the population dynamics of northern temperate stream fi sh, challenging the ability of fi sh to physiologically and behaviourally adapt. In this issue, Watz et al. show that brown trout (Salmo trutta) that spent the winter under ice cover grew more and used a broader range of habitats than trout in uncovered stream sections. These results indicate that the presence of surface ice may function as overhead cover against terrestrial piscivores and improve the energetic status of stream fish during winter.”

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

Douglas A. Jones har tillsammans med Eva Bergman och Larry Greenberg från NRRV och Karlstads Universitet nyligen publicerat en artikel med titeln “Food availability in spring affects smolting in brown trout (Salmo trutta)”. Studien handlar om födotillgångens inverkan på smoltifiering hos öring där låg födotillgång under våren verkar leda till att en högre andel öringar smoltifierar under samma vår. Artikeln publicerades i tidskriften Canadian Journal of Fisheries and Aquatic Sciences. I abstractet skriver författarna:

“Prior to out-migration, salmonid fish typically undergo physiological and morphological changes — a process known as smolting. This study indicates that smolting in brown trout (Salmo trutta) is affected by feeding conditions in spring immediately prior to out-migration. This conclusion was reached after experimentally testing the effect of seasonal variation in food availability on smolt status in the spring. A migratory strain of trout was administered either high or low food rations in the autumn, winter, or spring prior to release in the spring. While fish growth or condition could be affected in any season, it was spring rationing that reduced growth and growth-related variables and that caused increased smolting. Our result supports the idea that smoltification and the decision to migrate is affected by spring food availability regardless of conditions in the previous autumn or winter.”

Ladda ner artikeln här. Har du inte tillgång till tidskriftens innehåll men ändå vill läsa artikeln, kontakta någon av författarna.

oring

En ung öring bland fin ved (foto: Anders Tedeholm)

Den vetenskapliga artikeln “Effect of fine wood on juvenile brown trout behaviour in experimental stream channels” av Åsa Enefalk och Eva Bergman, publicerades nyligen i tidskriften Ecology of Freshwater Fish. Artikeln presenterar en studie där författarna undersökt unga öringars beteende i strömakvarier med olika mängder fin ved. I artikelns abstract sammanfattar författarna studien:

“In-stream wood can increase shelter availability and prey abundance for stream-living fish such as brown trout, Salmo trutta, but the input of wood to streams has decreased in recent years due to harvesting of riparian vegetation. During the last decades, fine wood (FW) has been increasingly used for biofuel, and the input of FW to streams may therefore decrease. Although effects of in-stream FW have not been studied as extensively as those of large wood (LW), it is probably important as shelter for small-sized trout. In a laboratory stream experiment, we tested the behavioural response of young-of-the-year wild brown trout to three densities of FW, with trout tested alone and in groups of four. Video recordings were used to measure the proportion of time allocated to sheltering, cruising and foraging, as well as the number of aggressive interactions and prey attacks. Cruising activity increased with decreasing FW density and was higher in the four-fish groups than when fish were alone. Foraging decreased and time spent sheltering in FW increased with increasing FW density. Our study shows that juvenile trout activity is higher in higher fish densities and that trout response to FW is related to FW density and differs from the response to LW as reported by others.”

Ladda ner artikeln här. Har du inte tillgång till tidskriftens innehåll men ändå vill läsa artikeln, kontakta någon av författarna.