Baltimore County, Maryland, May 16, 2008
The sky was overcast and a light drizzle of rain was falling as Jin and I arrived at the Masemore parking lot for an afternoon of fishing on the Gunpowder River.

One of the first things we noticed was the heavy growth of scum on the bottom of the stream. Portions of the stream bed and rocks were covered in what looked like thick, brown rope. It was
didymo, an invasive algae.

Didymosphenia geminata, commonly called didymo, is a freshwater microscopic diatom found in streams and rivers across much of North America. Also called "rock snot," didymo travels from stream to stream on fishing gear and on the bottoms of felt waders. Didymo poses a threat to aquatic ecosystems because it forms extensive mats on stream beds with a texture similar to wet wool, choking out aquatic insects and spawning beds.

Because it is easily spread, anglers are being urged by Maryland fish and game to sanitize all gear before leaving a stream. Boots, waders and other gear should be disinfected in a solution of one pound of salt to five gallons of water or scrubbed down in dish detergent (Palmolive, Dawn, etc.) and rinsed well. Didymo can survive on moist surfaces for two days.

The section of river bottom from the Masemore bridge upstream to the bend was covered with this stuff. I snagged bottom while nymphing and pulled up a nasty mess on the hook that was so foul that I cut off the fly and tied on a new one (I kept this fly in a used plastic film canister and soaked it in a soapy solution at home).
The action was very slow. Jin started with a size 16 paranymph and picked up a quick strike that was a Long Distance Release (LDR) but that was about it for this section. Fishing above the bend produced more hits and after a few more LDR for Jin he brought a fish to hand while skating his fly.

I followed behind Jin, nymphing the deeper pools and runs with no luck. At the deep pool at the river bend I saw trout begin to take off the top so I switched to a size 18 Pale Morning Dun and promptly pulled the fly out of the mouth of two trout in a row. These trout are smart. If you miss them on the first try, just move on to the next spot. Changing the fly might help, but if you miss, they won't be back.
We fished until 8:30pm, hoping that a hatch might come off but nothing happened so we called it a day and headed back to Virginia for dinner.

EQUIPMENT: Use anything from a 3 to 6 weight rod depending on the size of fish you are after. Leaders 9 to14 feet long at 4x or 5x are good for general use but lighter tippet up to 7x and longer might be needed earlier or later in the year. Check the Backwater Angler fly shop for more details.

DIRECTIONS: Take I-95 towards Baltimore then left onto I-695 to Towson. Take Exit 24 and merge onto I-83 Timonium/York, PA. Take Exit 27 Mt. Carmel Rd/MD-137 toward Hereford. Turn left onto 137 (Mt. Carmel Road) and follow for 1/4 mile. Turn left onto Masemore Road and slowly follow the narrow road downhill and past the old stone house on the corner. Fly fishing parking is just before the Masemore Road Bridge.