First I'd like to beg your pardon for being so late on writing my history. I began talking about autumn, but time went by and now I can't find the draft indeed in the list!
The reason on me being so late is a very little one. It's called Zebra mussel, and it appeared in Spain some years ago, althought it is a very old inhabitant in west and central Europe.
This little animal is a very dangerous one depending on the place it lives... It used to live in the Caspian and Black Seas, which shared with other species in peace.
The problem seemed to began when some big ships took accidentally lots of zebra mussel larvae in its ballast waters, and spreaded them all across Europe and North America. Then, our little mollusk became an invasive species, and its huge ability to increase its population produces a lot of problems, covering every water place, every substrate, everything... as you can see in the pic!
Althought this mussel had already colonized some zones of my country, it wasn't known to be in my region, till a month ago, when some larvae where found in a big lake... Then my workplace became a mess, and me and a workmate were "awarded" with a funny task: To look for these mussel all around La Rioja, searching in every humid place... so this month we have been more time in water than out of it! We were beggining to dare to become something like Bootstrap Bill, but at last we finished!
It has been a hard job, but finally we have a "mussel map" of this region, wich allow us to decide what to do now... We are no very optimistic about it, but we'll try, as other regions, to control as possible this little mollusk, that will be the worst enemy of the other bigger (but weaker) native mussel in our rivers and lakes...