Record Details
Floodplain emergent wetlands as rearing habitat for fishes and the implications for wetland enhancement
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Floodplain emergent wetlands as rearing habitat for fishes and the implications for wetland enhancement |
| Names |
Henning, Julie A.
(creator) Gresswell, Robert E. (advisor) Fleming, Ian A. (advisor) |
| Date Issued | 2005-02-28 (iso8601) |
| Note | Graduation date: 2005 |
| Abstract | Seasonal emergent wetlands in the Pacific Northwest have not been regarded traditionally as fish rearing habitat, despite access to such habitat when river flows overtop riverbanks and connect to the floodplain. As a result, restoration and enhancement projects to remediate for the loss of such wetland habitat are being implemented for waterfowl and other wildlife with little consideration for fishes such as juvenile salmon (Oncorhynchus spp.). The objectives of this study were to examine the degree to which fish utilize emergent wetlands and to determine the influence of wetland enhancement on fish communities in the Chehalis River floodplain. Furthermore, I quantified the influence of enhanced wetlands on juvenile coho salmon. A minimum of 18 fish species utilized floodplain wetlands, and the most abundant were three-spine stickleback (Gasterosteus aculeatus) and Olympic mudminnow (Novumbra hubbsi). Both enhanced and unenhanced emergent wetlands had higher abundances of nongame native fishes than oxbow habitats. Coho salmon (Oncorhynchus kisutch) was the dominant salmonid at all sites and enhanced wetlands had significantly higher abundances of yearling coho salmon than unenhanced wetlands. Dissolved oxygen concentrations decreased in emergent wetlands throughout the season and were near lethal limits for juvenile salmon by June each year. Survival of fishes utilizing emergent wetlands was dependent on movement to the river before water quality decreased and/or the wetland became isolated and stranding occurred. Emigration patterns suggested that coho salmon yearling and young-of-the-year emigrated as habitat conditions declined. This was further supported by the results of the experimental release of yearling coho salmon. Yearling coho salmon benefited from rearing in enhanced wetland habitats where their growth and survival were comparable to studies of juvenile coho off-channel habitats. |
| Genre | Thesis/Dissertation |
| Topic | Coho salmon -- Washington (State) -- Chehalis River Watershed |
| Identifier | http://hdl.handle.net/1957/22454 |
