As salmon and trout populations decline in the Pacific Northwest, emphasis should be placed on restoration of any stream capable of producing salmon and trout. Terrell Creek is a small, dam regulated, independent drainage that historically produced at least four species of salmon and trout. Streamflow, regulated at the Lake Terrell dam, has typically been close to zero during the summer low flow period and probably affected salmon and trout population levels in the Creek. This study was designed to characterize the current fish assemblage in Terrell Creek, estimate coho salmon (Oncorhynchus kisutch) smolt production levels, identify factors that limit coho salmon production, explore modifications to stream habitat and their potential impact on coho salmon smolt production, and recommend instream flow levels and management strategies that would increase levels of salmon and trout produced from Terrell Creek. Smolt traps were operated in two consecutive years to determine total salmonid production in the Creek during this period. Summertime streamflows were augmented with water from Lake Terrell. Instream temperatures were recorded during the flow augmentation period, and changes in useable stream area were measured at each discharge. Production of coho salmon, rainbow trout (Oncorhynchus mykiss), and chum salmon (Oncorhynchus keta) is low. Coastal cutthroat trout (Oncorhynchus clarki clarki) may have been extirpated from Terrell Creek. Water temperatures exhibited a general cooling trend from the dam to downstream sites, and rearing habitat increased discharge. This study concluded that 1) a potential increase in coho smolt production levels is possible only with an increase in available rearing habitat, 2) to increase rearing habitat during the critical flow period, flow augmentation must occur, and 3) Lake Terrell is an adequate water source for flow augmentation, in the context of instream temperatures and flow quantity
