Didymo is a serious concern here as it could seriously affect the trout fishery. Also called "rock snot" it thrives in clean flowing water, the exact same conditions that makes for good trout habitat. It was most likely brought to NZ from a tourist flyfisher from the US, a stowaway on his gear. In the US it does not seem to be a major problem but in NZ it has reached plague proportions on some South Island waters, and is spreading by the week. Mostly spread by recreational river users but possibly also by water birds.

A year after its discovery the officials have suddenly decided that felt soles could be a major vector for transfer, would have been nice to know this sooner! Disinfecting through use of detergents had been recommended until then. Now they reckon that felt soles are their own little ecosystems that take a long time to get properly dry and in the meantime harbour a vast array of eggs, larvae and spores from all sorts of creatures. Heat treatment or allowing time for the soles to get completely dry is now the recommended treatment for felt soles when moving between river catchments. In some areas of the SI felt soles are now banned and river users need to find alternatives. Aquastealth seems to be a favourite.

I love my felt soled wading boots so have been reluctant to make the change. Until now it hasn't been much of an issue as I hardly ever fish two catchments in such a short space of time that my gear doesn't dry completely. But I feel that I need to replace my boots soon, particularly if (when?) didymo hits the North Island.

I remember a post that referred to snot in the Vaal. Is this the same thing?