The Hendrickson nymphs we seined from the South Branch two weeks ago were nearly mature. For those of you wondering how we would know that - there are two primary indicators: the size of the nymphs; and the almost black, fully developed wing cases. Nature also provides us with clues, such as tree buds (the buds on sugar maple trees will be about the size of a peanut, and the pussy willows will have sprouted their fuzzy buds), forsythia and daffodil flowers pop open, and the spring peepers will be in full chorus at night just before the hatch begins.
What they are waiting for now is several days with water temperatures in the low 50's during the day. Looking at the indicators and the forecast, we should see the hendricksons begin hatching by early next week. By the following weekend it should be around peak on many of our north central rivers.
This is one of our best hatches, so be prepared and get out if you can, preferrably during the week as the weekends can be like rush hour on a lot of streams during in-season stocking.
In the meantime, there have been good hatches of Little brown and black Stoneflies and Blue-wing Olives on many streams. Where they occur, the Quill Gordons and Blue Quills are hatching now as well on NJ rivers. Keep in mind, the Big Flatbrook River is an exception and generally the hatches occur 1-2 weeks later than the Pequest, Musky or South Branch.
Life is good. Go fish!