Year Established: 2017 Start Date: 2017-03-01 End Date: 2019-02-28
Total Federal Funds: $24,926 Total Non-Federal Funds: $13,460
Principal Investigators: Eric Palkovacs
Abstract: Habitat can influence predator-prey interactions (PPIs) through a multitude of pathways by affecting predator and prey behavior and physiology, ultimately determining whether native prey is consumed by a predator. In California, the Sacramento-San Joaquin Delta is a highly human impacted system with habitat alterations and non-native predacious fishes which likely interact to affect native juvenile salmon. This study will explore PPIs between native juvenile salmon and nonnative striped bass on the Lower Mokelumne River (LMR), California. The specific objectives are to (1) examine how bank habitat and salmon attributes influence predation rates by striped bass and salmon movement behavior, (2) estimate the population-level impact of striped bass predation on emigrating juvenile salmon on the LMR, and (3) develop a predation model to assess increases in salmon survival under different management scenarios. To address objective 1, we will send tagged juvenile salmon through an experimental enclosure in the river containing striped bass and calculate losses due to predation and observe salmon migration behavior. We will analyze how levee habitat and salmon attributes influence predation rates and movement behavior. To address objectives 2 and 3, we will combine pre-existing survey and monitoring data with habitat-specific predation rates acquired in objective 1 to build a predation model. With this model we will estimate the population level impact of striped bass on juvenile salmon survival on the LMR, and alter parameters that mimic management strategies, such as predator removals, and habitat restoration to evaluate the efficacy of different strategies on increasing juvenile salmon survival.