Hook, Line and Sinker: May 12, 2010

The first weekend of May had many local residents shaking their heads in disbelief, especially those of us who awoke on Saturday morning with the wood stove still relieving the chilly temperatures of the night before, and then feeling a midsummer-like wave of heat the very next morning and watching the thermometer reach 90 degrees before noon! With so many signs of nature showing two weeks ahead of time, about the only thing one can count on is “un” usual and “un” seasonable weather.
Last Saturday I wandered along the banks of the river searching for the last of the fiddlehead ferns, a delicacy much anticipated at our dinner table during the spring. They had erupted at least 10 days early this year; and as I walked along, I picked a bouquet of deep purple violets and cheery forget-me-nots. I also pulled out several clumps of Garlic Mustard, that invasive species that is slowly taking over fields and wooded areas near the roadways. What made the experience noteworthy was the date, May 1. Here again was another reminder of nature being almost two weeks ahead of what we are accustomed to. The blooming of the violets and forget-me-nots (and the garlic mustard) usually coincides with the appearance of March Browns on the river. While we have not seen any March Browns yet, (the March Brown hatch here in the Delaware watershed rivers of the Beaverkill, East and West branches of the Delaware River doesn’t usually occur till mid-May) the hatch is much-anticipated by fly fishers and is considered a favorite – not necessarily due to the numbers of flies on the water, but rather due to the size of the fly, and its ability to lure large brown trout into rising.
The March Brown is a very large mayfly (about size #10) of the Stenonema genus that hatches somewhat sporadically during the day. It is similar to the Gray Fox, a smaller Stenonema; (about a size #14) both are tannish, lighter brown colored mayflies that usually hatch in our watershed in mid-May. These mayflies hatch during the day and provide good fishing for about one to three weeks. The March Browns spend a relatively long time on the water’s surface exiting their nymphal shucks and then attempting to take flight – sometimes for more than 30 seconds – and will remain on the water for that period, giving the trout a large ”target” and good feeding opportunity. The hatch usually begins in Pennsylvania and the Catskills in the middle of May; peaking in late May-early June. For the remainder of June and early July the hatch moves up into the Adirondacks, New England, and the Upper Midwest.
As with other mayfly species, there are two adult life stages that have specific names – Duns and Spinners. When the flies first emerge from the water, after exiting their nymphal shucks, they are called Duns (not to be confused with the color “Dun” that is a brownish-gray color commonly used in tying flies.) The scientific term for “Dun” is “Sub-Imago.” The second adult life stage of the mayfly occurs after molting – usually on land. They molt into a fully mature stage called the “Spinner” stage (the scientific name for this stage is “Imago”) during which they mate and deposit their eggs. Afterward they become weak and then eventually die. Most spinners fall to the water in the evening, which is where the term “evening spinner fall” is derived.