HR: 16:45h
AN: NB24C-06    [Abstracts]
TI: Effect of Spawning Salmon on Seasonal Changes in Structure and Function of the Macroinvertebrate Community of Kennedy Creek
AU: * Honea, J M
EM: jhonea@u.washington.edu
AF: University of Washington College of Forest Resources, Box 352100, Seattle, WA 98195 United States
AU: Gara, R I
EM: garar@u.washington.edu
AF: University of Washington College of Forest Resources, Box 352100, Seattle, WA 98195 United States
AB: This study investigated the hypothesis that spawning salmon affect macroinvertebrates negatively and positively-the former due to the disturbance of redd excavation and the latter due to nutrients released during spawning and salmon carcass decomposition. To test this hypothesis, I monitored changes for five seasons in density, biomass, and salmon-derived carbon (C) and nitrogen (N) in the benthic macroinvertebrates of a small stream with a large run of chum salmon (Oncorhyncus keta). Stable isotope analysis showed that the macroinvertebrates contained salmon-derived C and N year around, as indicated by the results of pre-spawning samples: 20-41% salmon-derived C and 25-50% salmon-derived N, representing 22% of total macroinvertebrate biomass. Near the end of the spawning run, all macroinvertebrates sampled showed increases in salmon-derived C (41-68%) and N (51-87%) incorporated into their tissues; however, the total macroinvertebrate biomass decreased due to redd excavation. The percentage of salmon-derived C and N in macroinvertebrates remained high 3 months after spawning (49-88% and 60-97%, respectively). Because total macroinvertebrate biomass also increased, this period had the highest salmon-derived macroinvertebrate biomass (2.71 g m-2). Six months after spawning, there were no detectable differences in total macroinvertebrate biomass between reaches with and without salmon.
DE: 1845 Limnology
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly