| Abstract | Introduction | Procedure | Results | Literature cited |

Discussion

Twenty-four small, mostly intermittent, Sacramento River tributaries were sampled for the presence of juvenile chinook salmon. All streams with a near-mouth gradient of less than 1% contained juvenile chinook. In most of the streams, there was a marked gradient of juvenile size, with smaller individuals nearer the mouth, as would be expected of non-natal rearing. Olney Creek and Bear Creek had what appeared to be both non-natal and natal cohorts. Adult carcasses were observed in Churn and especially Sulphur Creeks, but both developed interrupted flow before emerging fry were seen.

There was a great deal of variation between streams in numbers of juveniles present and distance they moved upstream, but no strong correlations with environmental factors could be found.

Tributary-rearing chinook grew rapidly and improved in condition. Individuals of the correct size to be members of each of the four Sacramento chinook races were observed. However, the combination of rapid tributary growth and lack of information about how long a given fish had been in the tributary made race assignments based on size questionable.

For most streams it was not practical to quantitatively sample enough sites to adequately estimate total juvenile chinook present. Estimates ranging up to 32,000 were made for three streams but no statistical limits could be placed on them. Also, quantitative values obtained in such an unusual water year may provide a very misleading picture of typical conditions.

Several lines of reasoning suggest that numbers, size diversity, and distance traveled upstream were lower this year than they would have been in a year with more evenly distributed rainfall. Further study is essential.

Lack of late-season rainfall resulted in juvenile chinook being trapped in some of the smaller tributaries, but most streams continued running long enough for juveniles to reach smolt size and emigrate successfully.

Intermittent tributaries provide habitat for many species other than salmon. Most species present were natives, rather in contrast with the usual situation in California waters. Native species, as might be expected, have life cycles synchronized with seasonal water flows.

Humans have historically attempted to dominate nature, including streams. Unfortunately, dominance without understanding the physical and biological dynamics of the system, has resulted in simplification and fragmentation of fish habitat (Reeves and Sedell, 1992). Consequently all the streams we investigated could be enhanced by changes in the way humans attempt to manage them. Some are functioning effectively as salmon habitat but could be still better with a few minor changes. Others provide very little and very poor habitat and can only be fixed with major investments of time and resources.

Should we spend our limited resources on the good streams and "write off" the bad ones? That would be a politically sound decision, but, unfortunately we have no way of knowing how much of the support (eco)system is essential to the continued survival of salmon stocks. Perhaps none of these small streams are important. That general attitude has led to the loss of "unimportant" chunks of habitat here and there until the continued existence of salmon is in doubt. We are learning that the support system and the life history of salmon is far more complex than was assumed in previous management practices. A specific problem approach to salmon restoration has rarely produced satisfactory results (Lichatowich, et al., 1995). An ecosystem approach must include the principle that these small streams are tied into the larger system by myriad physical and biotic links. Changes in tributaries imposed by human activities have affected the whole in ways we will probably never fully understand. The safest and most conservative approach would be to ensure preservation of existing natural habitat and begin restoration of degraded habitat to mimic historical conditions wherever possible.