So far I have only seen that didymo stuff – otherwise infamously known as “Rock Snot” on Television. I didn’t realise it grabs your spinners – but I guess it would too! Thankfully I haven’t seen it yet in the Rakaia or Waimakariri Rivers. Fish and Game took the wise precaution of closing several of the Rakaia’s tributaries to anglers this season in the hope of keeping it out of the main salmon spawning streams. Sounds like awful bloody stuff. I can’t imagine how you would get rid of it out of a waterway once it has become established.
Yeah I have heard a rumuor that copper or some other metal kills it? Anyway though it may look like crap, I have been fishing in the waiau and it was absolutely clogged with the stuff and it was one of the best trout fishing days of my life so, don’t discount rivers because of didymo.