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Didymo – Coming soon to a river near you

Didymo, it seems, is on its way. Canada has it in the Petite Cascapedia, Cascapedia, Nouvelle, Sainte-Anne,
didymo growth in BattenKill, NYBonaventure, Matapedia, Patapedia and Humqui rivers. Didymo is also stateside as  you can in the picture on the left.  Those Didymo covered rock are in the Battenkill, New York section.  It’s in Vermont’s White River as well and the Upper Connecticut has recently been added to the list.  Lakes are also subject to infestations and New Hampshire’s Lake Francis in Pittsburg has recently been added to the list if waters containing Didymo – it has been found above, in and below the lake.  So is it in Maine?

Well, not yet.  At least it hasn’t been discovered and reported.  But we are literally surrounded.  So what can be done to prevent Didymo from spreading to Maine?  some people are calling on a ban of felt soled wading boots, others are promoting education and cleaning methods and some, unfortunately are just saying you can’t stop it so live with it when it gets here – it’s our only choice.

I guess I fall into the second group.  I’m definitely not in the third group I won’t accept it as an inevitable yet uninvited guest to our state.  The first group – the ban the felt crowd – is onto something but I have concerns about the ban of felt.  Safe wading being my strongest concern.  Felt is the single best boot sole I know of for safe wading.  I know there are rubber sole wading boots out there but if they don’t have studs in them rubber soles don’t do the job on mossy, algae covered rocks – in my opinion.  And in the opinion of a lot of product development guys who are constantly testing rubber soles.  The product development guys I’ve talked to have told me their standard equipment for testing rubber sole wading boots consists of the boots, waders and two wading staffs – yes two wading staffs because without them they would be swimming not wading.  But even if they find a good rubber sole is a felt ban the answer?

I’m not sure.  I fear a ban on felt soles would give the impression that if you aren’t using felt you’ve got nothing to worry about.  A false impression for sure because boot laces, wader gravel guards, wading belts, line and backing – anything that gets wet and isn’t cleaned, dried or frozen before you enter anther watershed can carry Didymo.  But a ban on felt soles would raise awareness and that’s a strong argument.  I only know a few fly fishers that wouldn’t effect.  Talk about getting the word out – that would do it.

I don’t Using a Kitchen Freezer to kill Didymohave any answers to offer.  I can tell you I’ve decided to treat EVERY WATER I FISH IN AS THOUGH IT IS CONTAMINATED – EVERY WATER.  That way if Didymo is there but I don’t know it at least I won’t take it with me. I regularly freeze my felt soled boots. (Click to watch a video showing the freezing results) Freezing is an approved method of killing Didymo and unlike drying it doesn’t take 48 hours.  So if I fish Shawmut today and I’m headed for the East Outlet tomorrow (even though they are in the same watershed) my boots, waders and reel go into the freezer.

That’s great if you’ve got the luxury of a freezer but what about a weekend trip to the West Branch, then Kokadjo and finally the East Outlet with may a stop in Bingham on the way home.  A lot of people are telling me they use a bleach solution between watersheds but I’m not so sure that does it.  Bleach solutions (2 – 5%) are recommended for hard, non-absorbent surfaces like boat hulls, tires and fly rods – not felt.  Here’s a quote from New Zealand’s cleaning recommendations website.

“CLEAN: There are several ways to kill didymo. Choose the most practical treatment for your situation which will not adversely affect your gear.

  • Non-absorbent items
    • Detergent: soak or spray all surfaces for at least one minute in 5% dishwashing detergent or nappy cleaner (two large cups or 500mls with water added to make 10 litres); OR
    • Bleach: soak or spray all surfaces for at least one minute in 2% household bleach (one small cup or 200mls with water added to make 10 litres); OR
    • Hot water: soak for at least one minute in very hot water kept above 60 °C (hotter than most tap water) or for at least 20 minutes in hot water kept above 45 °C (uncomfortable to touch).
  • Absorbent items require longer soaking times to allow thorough saturation. For example, felt-soled waders require:
    • Hot water: soak for at least 40 minutes in hot water kept above 45 °C; OR
    • Hot water plus detergent: soak for 30 minutes in hot water kept above 45 °C containing 5% dishwashing detergent or nappy cleaner; OR
  • Freezing any item until solid will also kill didymo.

DRY: Drying will kill didymo, but slightly moist didymo can survive for months. To ensure didymo cells are dead by drying, the item must be completely dry to the touch, inside and out, then left dry for at least another 48 hours before use.

If cleaning or drying is not practical, restrict equipment to a single waterway.

NOTE: The thicker and denser the material, the better it will be at holding moisture (and live cells), the slower it will be to dry out and the more difficult it will be to soak completely with cleaning solutions.”

Hot Water Bath for Didymo TreatmentSo while I’m sure the bleach wash is better than no treatment I think when moving from the West Branch to the Roach in Kokadjo that I’m going to opt for the hot-water bath (for my gear anyway). I found heating the water and soaking gear for 40 minutes is about a two hour process.  All you need for the operation is a pan or pail, camp stove and an igloo cooler.  You can see the whole process as I first did in by clicking here and watching the video.

Two hours may seem like a long time but it really isn’t.  If you camp overnight on the West Branch you can set the gear to soaking and go to bed.  When you get up in the morning you’ll have safe gear soaking in the cooler.  And if you’re traveling from one watershed to the other all you have to do is heat the water before you leave and put the gear to soaking.  By the time you get to your destination and eat your lunch the gear will have soaked long enough to be safe.

Do I think Didymo is inevitable – no.  Do I think neglect by a single angler, boater, kayaker or canoeist can bring Didymo to Maine – yes.  Am I going to treat my gear between EVERY WATERSHED as though the watershed I just left is contaminated – yes.  Will it be me who brings Didymo to a watershed – no.   Will it be you?