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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

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Caryn Vaughn (left) asking questions to Lea Schneider (right) during the PhD-defense.

Today Lea Schneider successfully defended her PhD-thesis ”Conservation ecology of the thick-shelled river mussel Unio crassus – the importance of parasite-host interactions” at Karlstad UniversityCaryn Vaughn (University of Oklahoma, USA) was the opponent, and Leonard Sandin (Swedish University of Agriculture), Niklas Janz (Stockholm University, Sweden), and Annie Jonsson (University of Skövde, Sweden) constituted the grading committee (betygskommitté).

Lea Schneiders supervisors during her PhD were Martin Österling and Anders Nilsson from Karlstad University, and Johan Höjesjö from the University of Gothenburg, Sweden. Her work constituted on part of the LIFE-project UCforLife – Målarmusslans återkomst.

The thesis is available here. Contact Lea Schneider for questions and additional information.

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According to tradition, Lea Schneider (center) last week nailed her thesis to the wall, at the entrance to Karlstad University. On the photo are also Martin Österling (supervisor) and Reine Lundin (dean).

On February 24, Lea Schneider, will defend her PhD-thesis ”Conservation ecology of the thick-shelled river mussel Unio crassus – the importance of parasite-host interactions”. In the abstract Lea Schneider writes: ”Unionoid mussels are globally threatened and their conservation requires species-specific knowledge on their ecology and parasite-host interaction. Unio crassus is one of Europe’s most threatened unionoid species and has a temporary obligate parasitic life stage (glochidia) on fish. A lack of suitable hosts is probably a major limitation for mussel recruitment, but host species composition, suitability and availability in time and space have yet to be fully explored. This thesis examines different aspects of the host fish species, including their composition, suitability and ecological importance, in relation to U. crassus, using both field and laboratory studies. The effects of mussel and host density on mussel reproductive potential were considered, as were aspects of evolutionary adaptations between mussels and fish and how climate change may affect their interaction.

The results show that U. crassus is a host generalist, parasitizing a variety of fish species. Host suitability and density, which varied among fish species and rivers, affected the level of glochidia encapsulation, hence mussel reproductive potential, more so than the density of mussels taking part in reproduction. Ecologically important hosts included both highly suitable primary hosts, and less suitable hosts that were highly abundant. Whether or not U. crassus has specific adaptations to its hosts to enhance juvenile transformation remains unclear. No distinct pattern of local adaptation was found, nor was there an effect of host fish presence on the timing of glochidia release by adult mussels. Instead, temperature played a major role, with results suggesting that changes in spring water temperature regimes can cause temporal and spatial mismatches in the mussel-host interaction. This thesis indicates that investigations of local mussel-host interactions help in identifying mechanisms important for unionoid conservation management and prioritization.”

The defense will take place on February 24 at 10:15 in room 1B309 (Sjöströmsalen) at Karlstad University. The frame of the thesis is available online here.

For the defense, Caryn Vaughn (University of Oklahoma, USA) is the opponent, and Leonard Sandin (Swedish University of Agriculture), Niklas Janz (Stockholm University, Sweden), and Annie Jonsson (University of Skövde, Sweden) constitute the grading committee (betygskommitté).

In the afternoon (from 13:30 onwards) the day before the defense (Feb 23), seminars related to the thesis will be given in Room 5F416 at Karlstad University. Here Caryn Vaughn will present on ”Consumer aggregations act as hotspots of ecosystem function and services in rivers”, Niklas Janz on “What is host range?”, and Leonard Sandin on “Evaluation of ecological restoration in Swedish streams – some results from the EKOLIV project”. 

Everyone is welcome to attend both the PhD-defense and the seminars.

Klingavälsån i Skåne har restaurerats, delvis som en del av ett projekt att reintroducera den tjockskaliga målarmusslan i vattendraget. Restaureringen förväntas förbättra livsförhållandena för en mängd fiskar och andra vattenlevande organismer i ån. Som en del av utvärderingen av åtgärden elfiskas nu vattendraget och SVT-Skåne passade på att göra ett kort besök hos biologerna på plats. Bland flera andra fiskarter, hittades under dagen hittades Sveriges största rapporterade Grönling (Barbatula barbatula). Grönligen fick naturligtvis uppmärksamhet på TV. Se inslaget här:

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Om ungefär två veckor, den 28-30 September, arrangeras även ”International River Restoration Conference” i Lund. Konferensen är en del av projektet att återintroducera målarmusslan (UCforLife), och förutom en mängd intressanta föredrag så står även studiebesök till bland annat Kingavälsån på programmet. Det är fortfarande möjligt att anmäla sig till konferensen. Läs mer och se mötets pogram här.

The Fyleån creek (photo from uc4lifeconference.se).

The international river restoration conference “Restoring floodplains, habitats and connectivity using mussels and brains” will be held in Lund, Sweden, on 28–30 September, 2016. The organizers write: ”Conference objectives are to highlight experiences and results gained from a wide range of river restoration projects focusing on rehabilitation of species of freshwater mussels and fish. Mussels and fish are often used as indicators and flagship species while restoring rivers. But are they any good? If so – why? The first two days will focus on presentations by invited experts and conference participants who want to present their work. The third day includes field visits to Fyleån Creek, Klingavälsån River, both sites re-meandered, and the Hemmestorp Mölla rearing facility. We look forward to seeing you in Lund!”

Registration and more information on www.uc4lifeconference.se.

Martin Österling förevisar en tjockskalig målarmussla i samband med invigningen av den nyrestaurerade ån. Foto från Skånska Dagbladet.

För knappt två veckor sedan invigdes den nyligen restaurerade Klingaälsvån i Skåne. I en tidigare epok rätades vattendraget för att öka jordbruksproduktionen i området, nu har man återställt ett naturligt slingrande (meandrande) vattendrag. Restaureringen består, förutom återmeandring av vattendraget, också av försök att återetablera den tjockskaliga målarmusslan i ån. I slutändan förväntas åtgärden leda till ett mer naturlikt vattendrag och mindre läckage av jordbrukets näringsämnen till havet.

Den tjockskaliga målarmusslans larver lever som bekant en tid som parasiter på fiskars gälar. Som ett led av projektet har den tjockskaliga målarmusslans förhållande till olika fiskarter studerats. Forskningen om mussellarvernas förhållande till olika fiskarter har legat till grund för att fisk, såsom stensimpa och elritsa, fångats i ån, infekterats av mussellarver på lab och sedan åter släppts ut i ån. Från Karlstads Universitet har Lea Schneider och Martin Österling varit aktiva i projektet.

Läs mer om projektet på UCforLIFE.se. Skånska Dagbladet har också en artikel med flera foton från invigningsdagen. Läs den här.

UCforLife is a LIFE-project for river restoration and research related to the thick shellled river mussel (Unio crassus). Martin Österling, Lea Schneider, and Anders Nilsson at Karlstad University are involved in the project. The project is now announcing an upcoming international river restoration conference in Lund, Sweden, on 28–30 September. In the announcement they write:

”Conference objectives are to highlight experiences and results gained from a wide range of river restoration projects focusing on rehabilitation of species of freshwater mussels and fish. Mussels and fish are often used as indicators and flagship species while restoring rivers. But are they any good? If so – why? 

The first two days will focus on presentations by invited experts and conference participants who want to present their work. The third day includes field visits to Fyleån Creek, Klingavälsån River, both sites re-meandered,and the Hemmestorp Mölla rearing facility. 

Call for abstracts, oral or poster presentations, information about registration, fees etc will be available in July. We look forward to seeing you in Lund”

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Earlier this week Lea Schneider, PhD-student at Karlstad University, gave a presentation about her research on parasite-host ecology, local adaptation and conservation of the thick shelled river mussel. The seminar was titled: ”Local adaptation studies and conservation: parasite-host interactions between freshwater mussels and fish” and is now available online upon registration.

To access the seminar, send an e-mail to lea.schneider@kau.se.

Today Lea Schneider, PhD-student at Karlstad University, will give a seminar titled: ”Local adaptation studies and conservation: parasite-host interactions between freshwater mussels and fish”. The seminar will be given at 13:30 in room 5F416 on Karlstad University. Everyone is welcome to attend!

Read more about the thick shelled river mussel on NRRV.se or on UCforLife.