Growth of young-of-the-year salmonids in the Chena River, Alaska

Abstract

Growth of young-of-the-year Arctic grayling (Thvmallus arcticus), chinook salmon (Oncorhynchus tshawytscha) and round whitefish (Prosopium cylindraceum). was examined in the Chena River during 1981 and 1982. Each species exhibited a gradient of growth within the main river; faster growing fish were found downstream. Highest growth rates occurred in Badger Slough, a clearwater tributary that parallels the lower river. Fish condition followed a similar pattern; faster growing fish were heavier at a given size. Between year differences in environmental conditions affected the first appearance, distribution and growth of these species. Growth pattern was reflected on the scales of Arctic grayling. Faster growing fish had a greater number of circuli that were more widely spaced. For fish from the lower river and Badger Slough, the number of circuli formed by the end of the growing year was not significantly different between years. This characteristic may be used to identify Chena River Arctic grayling stocks.