Application of the Out-Migrant Survival Simulator using the SWARM modeling environment to study smolt-predator interactions: Modeling Support to Army Corps of Engineers Columbia River Fisheries Programs

W. Nicholas Beer
May 3, 1999 DRAFT

Project goals
The goal of this modeling exercise is to understand the sensitivity of certain assumptions regarding the behavior and interaction of smolts and their predators. We are interested to know whether fundamental behavioral attributes of predators and prey can be used to explain population level survival is observed in the field. When the key elements have been identified, we will apply the principles to an unknown and unstudied river condition (drawdown) in order to anticipate predator prey relationships.

Results of this exercise will include:

1. qualitative and quantitative descriptions of anticipated changes in smolt-predator interactions as a result of major changes in the hydrology of the Snake River (i.e. drawdown versus full pool)
2. sensitivity of changes in predator density, predator distribution and smolt mortality to a set of assumptions regarding predator behavior and environmental preferences
3. recommendations for incorporating these changes into CRiSP passage model
4. anticipation of the effects of drawdown on survival due to predation.