In 1999 we continued to investigate the use of small tributaries of the Sacramento River by juvenile chinook salmon. The main objective this year was to evaluate densities of rearing juveniles in the reaches of tributaries adjacent to the river. These reaches were found to contain substantially more juvenile chinook than upstream reaches suggesting that previous estimates of tributary use might have been low. The observed condition of tributary-rearing juveniles was somewhat lower than previous years but better than that of river-rearing juveniles. The lower condition observed this year probably relates to the emphasis placed on sampling near-river reaches of tributaries where fish average smaller and in poorer condition than in upstream reaches. Fish captured in upstream tributary reaches were comparable in condition to those observed in former years. Different races also showed different distributions within the tributaries, with winter chinook generally found further from the river. A summary of findings in other years is presented along with a discussion of possible restoration approaches.
This work was made possible by Grant # 1448-0001-96729 from the U.S. Fish and Wildlife Service under the authority of the Federal Grant and Cooperative Agreement Act of 1977 and the Central Valley Improvement Act.
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IntroductionAbstract: Tributary Rearing Salmon 99
Last Updated Aug. 28, 1999