2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/22/2019 | 9:30 AM - 9:45 AM | EFFECTS OF CARCASS ADDITIONS ON STREAM FOOD WEBS ALONG A FISH ASSEMBLAGE GRADIENT IN AN INTERIOR COLUMBIA RIVER BASIN TRIBUTARY | 250 CF
EFFECTS OF CARCASS ADDITIONS ON STREAM FOOD WEBS ALONG A FISH ASSEMBLAGE GRADIENT IN AN INTERIOR COLUMBIA RIVER BASIN TRIBUTARY
We added steelhead (Oncorhynchus mykiss) carcasses to three stream pairs in an interior Columbia River Basin
tributary to evaluate how the reduction of marine derived nutrient (MDN) subsidies in this region may be impacting
stream food webs. Juvenile salmonids were present in all three pairs (each with a control and
treatment) but the proportion of native non-salmonids increased with distance downstream.
Stable isotope analysis indicated that the majority of the food web – periphyton, various
macroinvertebrate guilds, and non-salmonids – assimilated MDN through bottom-up pathways in
the middle and downstream pair, but not the upstream pair. However, we estimated that most of
these taxa only obtained 5-12% of their energy from MDN. In contrast, across the three study
pairs, juvenile Chinook (O. tshawytscha) and steelhead obtained between 20-25% and 40-61% of
their energy from MDN, respectively. Juvenile Chinook and steelhead growth rates and body
condition were significantly greater in treatment reaches compared to controls 0-4 weeks after
carcass additions. Diet analysis clearly indicated that salmonid MDN assimilation and enhanced
growth were primarily attributed to direct consumption of carcass tissue and eggs. Diet analysis
further revealed that non-salmonids did not consume eggs or carcass material.
- Diet
- Invertebrate
- Food Webs
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Presenters/Authors
Matthew Kaylor
(), Oregon State University, matthew.kaylor@oregonstate.edu;
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Seth White
(), Columbia River Inter-Tribal Fish Commission, whis@critfc.org;
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Edwin Sedell
(), Oregon Department of Fish and Wildlife, edwin.r.sedell@state.or.us;
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Ashley Sanders
(), Oregon State University, a.sanders333@gmail.com;
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Dana Warren
(), Oregon State University, dana.warren@oregonstate.edu;
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