You are here:
EXPLOITATION OF FLOODPLAIN RESOURCES BY ADULT LARGESCALE SUCKER OF THE WILLAMETTE RIVER, OREGON
Citation:
LaVigne, H. R., C. F. Baker, AND P. B. Bayley. EXPLOITATION OF FLOODPLAIN RESOURCES BY ADULT LARGESCALE SUCKER OF THE WILLAMETTE RIVER, OREGON. Presented at 2001 Joint Annual Meeting Oregon Chapters American Fisheries Society and the Wildlife Society, Portland, OR, February 14-16, 2001.
Description:
We tested two predictions of the flood-pulse concept on a large, temperate alluvial river that historically flooded an extensive fringing floodplain. We predicted adult largescale sucker, Catostomus macrocheilus, would: (1) migrate onto the floodplain during high water; and (2) exploit terrestrial food. To test these predictions, we determined the location of radio-tagged adult largescale sucker and examined the gut contents of others captured on the floodplain during late fall and early winter high-water events of two successive years. Largescale sucker did move onto the floodplain when it became accessible and consumed small quantities of terrestrial foods. Radio-tagged fish used a variety of floodplain habitat including riparian forest fragments, open field-like areas and the base and tops of cobble-gravel point bars. Gill-net sets on open ground captured largescale suckers that had ingested mainly detritrus of unknown origin, aquatic invertebrates, including oligochates which may have excysted from previously exposed soft sediments, and limited quantities of terrestrial invertebrates. These results demonstrate that largescale sucker of the Willamette River migrate onto the floodplain when accessible and consume at least small quantities of terrestrial food resources. This suggests the adaptation of this riverine species to exploit its native floodplain.