interesting read about non-native shrimps invading the UK lakes.... seems our okanagon lakes have a similar problem and that is why government of canada allows Piscine Energetic to troll for the mysis shrimp:
read: more about the demon shrimp ( small, similar in size I think to mysis)
http://www.independent.co.uk/environ...s-9119045.html
and how mysis was introduced in western canada...
http://www.mysis.com/about/about_us/