Seasonal growth, retention, and movement of juvenile coho salmon in natural and constructed habitats of the mid-Klamath River
Graduation Date
2014
Document Type
Thesis
Program
Other
Program
Thesis (M.S.)--Humboldt State University, Natural Resources: Fisheries, 2014
Committee Chair Name
Darren M. Ward
Committee Chair Affiliation
HSU Faculty or Staff
Keywords
Beavers, Off channel ponds, Restoration, Seasonal redistribution, Humboldt State University -- Theses -- Fisheries, Seasonal refugia habitat, Coho salmon, Growth, Non natal rearing
Abstract
Juvenile coho salmon (Onchorynchus kisutch) in the Klamath River basin often move long distances when natal streams become inhospitable due to high summer temperatures and high winter flows. Therefore, non-natal rearing sites such as tributaries and off- channel ponds are potentially important to the survival of juvenile coho salmon. This study evaluated the potential benefit to juvenile coho salmon of different types of non-natal rearing habitats in the mid-Klamath watershed including tributaries, beaver-influenced ponds, and constructed off-channel ponds. These sites represent different types of seasonal refugia habitat. Juvenile coho salmon were PIT tagged and measured in ten study sites to evaluate their growth, retention within the habitats, and seasonal movement patterns. Few relationships were found between type of site and growth rate, retention rate, or abundance. However, growth rate of fish which reared year-round in the same site was greater in beaver-influenced sites than in other habitat types. Depth, water temperature, volume of habitat, and percent riparian cover were not correlated with growth rates of coho salmon rearing in those sites. However, because I found significant differences in growth rates of fish across individual sites, there may be other habitat characteristics not measured as part of this study that influence growth. Retention rate was positively correlated with average maximum depth; however the summer retention rate of juvenile salmon at the sites was not correlated with salmon growth at the sites. I observed three seasonal movement patterns of juvenile coho salmon: spring redistribution of fry; fall redistribution associated with initial high flows, and outmigration of smolts during the following spring. A diurnal movement pattern was also detected at the mouths of Tom Martin Creek and Caltrans Pond in which juvenile coho salmon left the study site in the evening and returned in the early morning. This exploratory study showed that not only do juvenile coho salmon in the mid-Klamath display several different migratory patterns; choosing different types of off-channel habitats to rear, but the growth and retention rates of those fish depend on complex and site specific characteristics rather than type of habitat.
Recommended Citation
Witmore, Shari K., "Seasonal growth, retention, and movement of juvenile coho salmon in natural and constructed habitats of the mid-Klamath River" (2014). Cal Poly Humboldt theses and projects. 2162.
https://digitalcommons.humboldt.edu/etd/2162
https://scholarworks.calstate.edu/concern/theses/6d56zz89d