Drying Required To Kill Didymo, Protect Our Maryland Waters

Didymo On The Hook
Over the past three years there is no denying that the “rock snot” has changed the aesthetics along the river and effective techniques during Winter months. Since this invasive was transferred to the Gunpowder its life cycle has become easier to follow. In the Winter the air and water temps hit the magic number and a tan peach fuzz begins to cover the rocks. In the following months from Jan-March the growths begin to cover wide expanses of the river bottom, and form long tendrils of grayish white snot. Those anglers who fished through this time frame the past few years know that at times the algae goes beyond frustrating, fouling the nymphs frequently. Fortunately just as quickly as it appeared in the Winter, the warmer water and higher flows of Spring start to flush the algae from the river bottom in April. Tippet knots, loop to loop connectors, and split shot also pick up small pieces of the cotton-like algae floating downriver. While frustrating, this break up process is a good thing. The algae looses its grip on the rocks and primarily is seen stuck on branches and logjams. Aside from slow water behind logjams, the algae seems to be a distant memory once the months of May and June arrive. There is still very little we know about Didymo in the Gunpowder and its effect on our hatches and trout, yet other waters may be affected differently. One thing we do know is we want to keep it out of as many of our Maryland rivers, and streams as possible.
Small Stream Bred Wild Brown Trout
In just two years after Didymo was found in the Gunpowder, it was discovered in the Savage River this Winter. It was alarming that a river over three hours away was infected so quickly when you consider the number of other C & R, Delayed Harvest, and small wild trout streams found across the state. For years many anglers enjoyed fishing multiple rivers over a weekend, especially in Western Maryland, New York and Pennsylvania. Just a few years ago it wasn’t uncommon to hear reports of anglers fishing one stream in the morning and another in the evening using the same gear. Now this practice is considered extremely high risk for transferring any number of invasive species, like Whirling Disease, Mud Snails, Didymo, etc. Fly fishermen on the Gunpowder are using the salt stations, or bleaching gear at home, but the critical part is DRYING. I’ve spoken to a few anglers at the parking lots on the Gunpowder over the years, who were bound for waters in Pennsylvania, Delaware or Virginia that same evening oblivious to what effect they may have on those watersheds. The Savage is also in an epicenter of great fishing, with numerous rivers and brook trout streams less than an hour away in multiple states. I’ve heard more horror stories than I care too really, because many are under the impression that “treating” gear with salt or bleach will prevent the spread of invasive species. The treating and cleaning gear isn’t the hard part, but the extended drying time for felt (5 days minimum) is too long a wait for many to abstain from fishing other waters. I wanted to post the information provided by MDDNR below as a reminder, because some are misinterpreting or unaware of the proper steps to avoid transferring Didymo. Once this invasive algae enters your home waters, as it has the Savage and the Gunpowder, becoming an advocate for preventing its spread comes naturally from dealing with this nuisance each Winter and Spring. Protect YOUR rivers and streams!

Follow these procedures for all but felt or fabric materials:
Clean with salt water (1 cup salt/1 gallon of water)
Soak for at least one minute, rinse well
Dry thoroughly until bone dry before entering other waters

Procedures for felt
MDDNR recommends not using felt, as felt is difficult to disinfect. Soak in salt solution for 40 minutes and rinse well
Dry felt Minimum of five days before entering other waters