With respect to didymo, cleaning gear is fairly easy. Warm water with dish detergent works fine as the detergent kills the didymo cells. Also, drying out the boots and waders completely works too, since didymo dries out and dies. Salt water will kill it as well, so if your boots and waders can deal with salt water, you can put 'em in brine. The issue with felt is that it takes much much longer to dry out the felt sole then the rest of the gear (or get the soap into the sole, where the didymo can "hide"). If you go from one water shed to another in the same day, you can track it no matter what gear you're using on the laces, etc. If, however, you dry your boots out by the heater over night thinking you're doing your bit, then go to a new area the next day, sure your upper boot and waders are sanitised, but the inner parts of the felt sole may still be damp, etc.
That, in a nut shell, is the guts of the argument for banning felt here in NZ. Even if you try and clean and dry your gear, felt just makes it too hard to do so.
Now, the science behind all of the above is sound. Yes, didymo will live much longer in the sole of felt boots then it does on the other parts of the boots or waders. Where the concern is, however, is that the science they cite as the reason for banning felt soles is the "wrong" science. The science they need to conduct is "how much spread of didymo is a direct result of transfer by felt soled wading boots"? Rather than, say, tramper's boots, boats (canoes, kyacks, outboard motors, etc), vehicles, peoples pets, swimming gear, etc. If felt soles are a major player then great, but remember the above science doesn't address that issue, it only addresses whether or not didymo survives longer in the felt soles. It does not address the issue of whether or not this translates to a high incidence of didymo transfer. For that, you need to examine whether or not wet boots do often move from one water system to another. You would have to examine angler behaviour, since it is the angler that moves the boots. It may be that anglers tend to remain in a single water system, so even if their boots get "infected", they are not transfering didymo to a new area as they move around. When the typical angler shifts to a new water system, the time between fishing trips may generally be long enough that even the soles dry out sufficiently, therefore rendering transfer by the soles highly unlikely). Boats, however, may tend to retain water for much longer, increasing the liklihood (and volume) of contamination. Hikers are more likely to cover large distances, through moutain regions, and therefore may be more likly to track material to separate water systems (should we ban hiking boots?). And so forth. In other words, yes, banning felt does ban a potential carrier, but there is no evidence that felt soles were the major carrier, or even a highly probable carrier, compared to all the other potential carriers, which were not banned.
Good science provides us with information. Misunderstanding what that information tells us is not the fault of the science. Unfortunately, deliberate misrepresentation of science is becomming more common in various forms of propoganda or by the press to sell more papers. Ironically, this leads to an increase in the mistrust of scientists rather than an increased mistrust in policy makers or reporters. Go figure.
- Jeff