Numbers, numbers and more numbers – a short summary of this years’ summer:

Written by Ivan on . Posted in BOB'S BLOG, Re-introduction of Unio crassus, Studies

After 214 days, more than 600 cups of coffee and several hundred popsicles out in the field in Scania autumn is coming to the mussel-lab.

The young mussels are now almost 1 mm = 1000 µm big (!) and are out in 4 different waterbodies that are part of the UC4LIFE project area. We will continue to measure growth and survival – to see how they are doing out there!

During the summer we succeeded placing out a total of 1000 juveniles in 200 small tubes that we can follow them during the autumn. Furthermore, we translocated 170 adult mussels to the two restored streams that are part of the project: Fyleån and Klingavälsån. Last but not least we also placed out some fish that are infested with mussel larvae (or so called glochidia) on their gills. With all that we hope the future of the mussels can start!

All the best from the mussel-lab at the Hemmerstorps mill,

The mussel crew (Valentina & Tina)

 

 

What’s for dinner?

Written by Ivan on . Posted in BOB'S BLOG, Re-introduction of Unio crassus, The thick shelled river mussel

Mussels are filterfeeders, which means they have to filter water to get nutrients. They take up nutrients through so-called detritus (dead organic matter from animals and plants), algae and dissolved particles in the water. During the summer we carried out a feeding experiment at Hemmerstorpsmölla where different types of food combinations were tested in order to find out what is most suitable for juvenile mussels. The mussels were fed with detritus from the stream, and combinations of detritus with algae and/or proteins. As control group acted a treatment where the mussels were fed no detritus. The survival and growth of the 880 juveniles were measured every second week.

The juveniles come from Bråån, a stream where there is a healthy mussel population of the thick-shelled river mussel (Unio crassus). We cultivated those mussels in the lab with the help of their host-fish: minnows (Phoxinus phoxinus). At the beginning of the experiment the juveniles were only 220-240 µm big, while now they are more than double the size: which means they are now over half a millimeter big! The results also suggest that it is most likely detritus that is the most important source of food for our mussels.

Now the juveniles get their favorite dish served until end of September when they will be placed out in the different streams that are part of the UC4LIFE+ project.

/UC-for Life Crew (Tina, Valentina and Martin)

 

Survival of juveniles in Klingavälsån River and Fyleån Creek

Written by Ivan on . Posted in BOB'S BLOG, Communication, Re-introduction of Unio crassus, River Fyleån, River Klingavälsån

juveniles

One year has gone by since the restauration of Klingavälsån, and two years for Fyleån, and we are now trying to find out how our cultured juvenile mussels (Unio crassus) respond to their new environment. This year a new method, Whitlock-Ö-boxes (2016) has been developed to test this. The Whitlock-Ö-box (2016) is a box constructed with holes in the walls so that water can flow thru it. Inside the box tubes with mussels have been placed and fixed. The tubes contain holes in the wall covered with a 200 um net, so that water can run through and the mussels stay inside. The box itself is attached to an iron stick at the bottom of the river. Every week the boxes are collected and brought back to the lab at the Hemmestorps Mill where survival rates are examined. The results so far are encouraging and the juveniles seem to like their new environment.

/ Tina, Valentina och Martin

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