Ebersole, Joseph L. ; Wigington, Parker J. Jr.; Baker, Joan P.; Cairns, Michael A.; Church, M. Robbins; Hansen, Bruce P.; Miller, Bruce A.; La Vigne, Henry R.; Compton, Jana E.; Leibowitz, Scott G. 2006. Juvenile coho salmon growth and survival across stream network seasonal habitats. Transactions of the American Fisheries Society. 135: 1681-1697. doi:https://doi.org/10.1577/T05-144.1
Understanding watershed-scale variation in juvenile salmonid survival and growth can provide
insights into factors influencing demographics and can help target restoration and mitigation efforts for
imperiled fish populations. We assessed growth, movement, and apparent overwinter survival of individually
tagged juvenile coho salmon Oncorhynchus kisutch in a coastal Oregon watershed from June 2002 to June
2003 and related growth and survival parameters to stream characteristics. Fall body size of juvenile coho
salmon was a good predictor of smolt size and survival, but smolt size was also influenced by overwintering
location. This was due to strong spatial patterns in winter growth rates associated with residency and
movement into a small intermittent tributary. Though nearly dry in midsummer, this stream supported high
densities of spawning coho salmon in the fall, and juveniles rearing there exhibited relatively high growth
rates and emigrated as larger smolts. Improved winter growth and survival of juvenile coho salmon utilizing
tributary habitats underscore the importance of maintaining connectivity between seasonal habitats and
providing a diversity of sheltering and foraging opportunities, particularly where main-stem habitats have
been simplified by human land uses.