For our post 4th of July Sunday morning, we’ve planned to schlepp gear to a few site along two of our rivers, the Kuparuk River and Oksrukuyik Creek, followed by a relaxing day of young-of-the-year (YOY) larval grayling hunting at Happy Valley. With the help of Matt in his R44 helicopter, we’re done slinging gear to our sites by 11:00 am. Traveling now by truck along the Dalton Highway, Cam and I parallel the Sagavanirktok River, heading North past the mouth of Oksrukuyik creek, through the “Ice Cut” to Happy Valley. Interested in population structure along a transect from South to North along the Sagavanirktok River, Happy Valley Creek serves as a sampling location for genetic differentiation. Here, we hope to collect YOY Arctic grayling for use in both genetic analyses and for building a standard curve for otolith (fish earbone) chemistry versus water chemistry. With only one GPS unit (a.k.a. my iPhone’s Gaia GPS app) with which to document the locations of our samples, Cam creates a YOY “Easter egg” hunt as we split up to cover more area. Later, I retraced his steps, obtaining both the samples and the geographic coordinates for each site. From the unusually brown tundra to the dry culverts on Happy Valley Creek, signs of a very dry summer surround us. Fortunately, at least for now, there remains enough water in the stream bed to support YOY and even a few juvenile Arctic grayling.
I start my post-celebratory Sunday stumbling bleary-eyed from my tent on Toolik Lake.
I’ve never seen the waters of Happy Valley creek this low before. Not good for adults, the warm pools formed by low discharge benefit YOY grayling growth, as long as the water temperature doesn’t get too high.