Permanence of Station in Juvenile Chinook Salmon and Steelhead Trout

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Abstract
Daytime movements and night locations of juvenile steelhead trout (Salmo gairdneri) and night locations of spring-run chinook salmon (Oncorhynchus tshawytscha) were observed in Johnson Creek and the Lochsa River in Idaho during the summers of 1965 and 1966. The observations were made by branding fish and observing them subsequently under water. The distances between sequential sightings of branded steelhead within each day and over longer periods were recorded. In 151 sequential sightings of steelhead within each day in Johnson Creek, 58% of the distances moved were less than 3 m and 86% were less than 6 m. In 59 sequential sightings of branded steelhead on successive days in the Lochsa River and Johnson Creek, 53% were less than 3 m and 68% were less than 6 m apart. In sightings of branded steelhead separated by 10–14 days, 45% (25) of the sequential sightings were less than 3 m and 63% were less than 6 m apart. Movements of spring-run juvenile chinook salmon within each day were measured in a stream aquarium (10.5 m long and 0.6 m wide). Of 272 observed daily movements, 65% were less than 0.6 m. Steelhead trout were inactive at night, occupying bottom areas of low velocity, usually inshore. During the day they were in areas of moderate current. Chinook salmon were observed at night to be both on the bottom and near the surface in quiet water, and on the bottom in flowing water. Chinook salmon were found at all depths in quiet water during the day. In winter, some steelhead trout were found in the substrate in the same area they occupied the previous summer.

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