High diversity of fish in the newly created Fyleån Creek

Written by Ivan on . Posted in Host fish speices, River Fyleån, Studies

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In total five fish species were caught by electro fishing in Fyleån Creek. These parts of Fyleån Creek were re-created during 2013 by re meandering measures. The species caught were brown trout, three spined stickleback, bullhead, minnow and European eal. Clear evidence of spawning activities by brown trout was also noted. Interestingly, four of the species (eal excluded) are identified as potential hosts species for the thick shelled river mussel during its parasitic stage. The ecological response post restoration is fast and strong, in a positive direction indeed.

The highest diversity, and most individuals caught, were at sites with high habitat variability (gravel, stones, woody debris and vegetation), whereas sites with homogenous habitats (sand and fine organic matter) corresponded to low diversity and few individuals caught.

Bank erosion expose high abundances of woody debris. Something to bear in mind while discussing how to increase the habitat variability in Fyleån Creek during future discussions?


Hello! I’m Jeroen

Written by Ivan on . Posted in BOB'S BLOG, Communication, Host fish speices, Team Members

Hello! I’m Jeroen (the man in on the right hand side), the new intern for this Unio crassus LIFE project. I study biology at the University of Applied Sciences in Almere, the Netherlands. For my study I’m doing this internship abroad for 12 weeks. So far I’m really enjoying myself, working in the lab and in the field. I’m interested in aquatic ecology so I’m happy that I can help you out, and I think it is very interesting. Unio crassus fulfils a very important role in the ecosystem and that is why it feels good to help restore old populations and help the research to find out what the main causes are and why the species has decreased in numbers.

Also, Bob sends his regards, I’ve seen him and his siblings yesterday and he is doing fine! In the meantime we have found even more of his brothers and sisters so they are doing just fine in the river. In the coming few weeks the family will be growing even bigger as I am sure we will find a lot more mussels.


Jeroen Jansen


KAU goes Stockholm: DNA-analyses at the Swedish Museum of Natural History in Stockholm (NRM) 07/ 04/ 2014

Written by lea on . Posted in Host fish speices, Karlstad University, Project sites, River Bräkneån, River Emån


Also this year, the UC4LIFE host fish mapping conducted in Emån and Bräkneån has been coupled with DNA analyses of mussel larvae. This means that fish caught in the two rivers in 2013 were examined for mussel larvae (glochidia) infestation first and glochidia could be picked from the fish gills. Kristin enthusiastically conducted this work over the winter that she and I could secondly bring our samples to Stockholm in March 2014. During three weeks of lab-work some preliminary results about the host fish use of the thick shelled river mussel in the two Swedish streams could be acquired.  Unio crassus larvae were found on common bleak, ruffe, minnow, brown trout, vimba, perch, roach and European chub. Anyhow, it seems that the minnow still represents one of the most important host fish species for Unio crassus. However, data needs to be analysed in detail.

I would like to thank Pia Eldenäs from the NRM enabling the DNA analyses and providing an excellent supervision, particularly also from Bodil Cronholm from the NRM lab-team.


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