Bone Dry

Cam and I collected water chemistry samples at locations along each of our three study watersheds, but this year water seems as difficult to “catch” as Arctic grayling were this spring.  With ultra-dry conditions prevalent across most of Alaska, current water level and flow across our study area ranged from zero to low.  While in some locations water flowed freely, in others we found only puddles, if anything at all, from which to draw water.  These samples will help us determine fine-scale variation in water chemistry, specific to each location within each river system.  You might wonder, “What does water chemistry have to do with fish?”  Well, I’ll tell you… Fish have earbones called otoliths.  Otoliths comprise layers of calcium carbonate, continually incorporating elements from the water that the fish is in over time.  This chemical signal becomes permanently embedded in the otolith.  So, as the water chemistry varies across the watershed, the otolith chemistry reflects that variation, allowing us to decipher past movement patterns of the fish throughout its lifetime.  So cool!