Fish & Water - Sounds Wild
Grayling research

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Grayling research

A biologist in a small plane is flying over the Goodpaster River in Interior Alaska. He's tracking a grayling, a fish that has been tagged with a radio transmitter to help biologists learn about grayling migrations. The radio tag is a small, internally implanted transmitter about half the size of a triple A battery.

The tag sends a signal that can be detected up to 10 miles away. Over a one to three year period each tagged Arctic grayling is located by periodic aerial surveys. Tagged fish are also detected and documented when they pass riverside radio tracking stations, set up at the confluence of tributary streams.

During summer, Arctic grayling are spread throughout the upper Chena, Salcha, and Goodpaster rivers and their tributaries where food is plentiful. As water cools in late August, fish leave the upper portions of drainages and move downstream to overwintering areas throughout the main stem of the rivers.

After overwintering, grayling typically migrate to their spawning areas in early May just before breakup. Spawning is over within two weeks of breakup, and then the grayling migrate to their summer feeding grounds. Some move less than 10 miles total throughout the entire year, but some move long distances. After spawning in May, one grayling traveled 105 miles to the Upper North Fork Goodpaster River in 15 days. Another grayling spent a summer in the Upper Goodpaster, overwintered in the main stem of the river, and then spent the next summer 114 miles away in the Delta Clearwater River.