Alaska Spring Fish Runs: Eulachon

On the Twentymile and Susitna rivers, usually in May. That timing comes from the Alaska Department of Fish and Game.

Each run card follows the usual months its source gives. The spawn itself waits on the water, so a river thermometer read against the spawning temperature on the card settles it: more than 5°F below the spawning temperature is Not yet, within 5°F is Getting close, inside the range is On, and above it late in the run is Winding down.

No. The months are the usual window, and the water sets the day: a cold spring holds a run back, and a warm one brings it forward. In Alaska, a reading at the river against the spawning temperature shows where the water stands.

Eulachon are a small Pacific smelt, also called candlefish, that run up Northwest and Alaska rivers.

Water temperature is the main signal: each species waits for its own range. Longer days bring fish toward the rivers, and a warm rain that raises and warms the water often starts a push upstream. Walleye go first in cold water; white bass, herring and shad follow as rivers warm.