Stock identification and homing of arctic grayling, Thymallus arcticus (Pallas), in interior Alaska

Abstract

The objectives were to determine techniques for identification of Arctic grayling Thymallus arcticus (Pallas) stocks in interior Alaska and evaluate homing. Starch gel electrophoresis was used to identify three stocks in the Tanana River and the upper Koyukuk River drainage. Photoidentification could not be used to separate these stocks based on the number of spots on their sides. The spot pattern seemed to have potential for identification of individual grayling. It was feasible to tag young-of-the-year grayling with coded micro-wire tags. The 30-day tag loss was high (27.8%) for the smallest, but significantly lower (7.7%) for the largest size group. Analysis of back-calculated fork lengths at first annulus indicated that Badger Slough and Chena River grayling represent separate stocks. Mature Badger Slough grayling had similar numbers of whole circuli to young-of-the-year grayling from Badger Slough, suggesting that they were homing to their natal stream.