Development and Evaluation of a Chinook Salmon Smolt Swimming Behavior Model

Edward S Gross,Michael J Thomas,Rusty C Holleman,Nann A Fangue,Andrew L Rypel

doi:10.3390/w13202904

Edward S Gross, Michael J Thomas + Show 3 more

Open Access

https://doi.org/10.3390/w13202904

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Journal: Water	Publication Date: Oct 16, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: University of California, Davis, Care Resource

Abstract

Hydrologic currents and swimming behavior influence routing and survival of emigrating Chinook salmon in branched migratory corridors. Behavioral particle-tracking models (PTM) of Chinook salmon can estimate migration paths of salmon using the combination of hydrodynamic velocity and swimming behavior. To test our hypotheses of the importance of management, models can simulate historical conditions and alternative management scenarios such as flow manipulation and modification of channel geometry. Swimming behaviors in these models are often specified to match aggregated observed properties such as transit time estimated from acoustic telemetry data. In our study, we estimate swimming behaviors at 5 s intervals directly from acoustic telemetry data and concurrent high-resolution three-dimensional hydrodynamic model results at the junction of the San Joaquin River and Old River in the Sacramento-San Joaquin Delta, California. We use the swimming speed dataset to specify a stochastic swimming behavior consistent with observations of instantaneous swimming. We then evaluate the effect of individual components of the swimming formulation on predicted route selection and the consistency with observed route selection. The PTM predicted route selection fractions are similar among passive and active swimming behaviors for most tags, but the observed route selection for some tags would be unlikely under passive behavior leading to the conclusion that active swimming behavior influenced the route selection of several tagged smolts.

Highlights

The Sacramento-San Joaquin Delta (Delta) (Figure 1) is a migration corridor and rearing habitat for juvenile Chinook salmon (Oncorhynchus tshawytscha) that emigrate fromCentral Valley rivers to the Pacific Ocean
The lowest estimated HOR Bias metric is for the surface orientation and rhethe surface
The route selection for each particle was determined by the first transit past the diffluence into Old River or the San Joaquin River

Summary

Introduction

The Sacramento-San Joaquin Delta (Delta) (Figure 1) is a migration corridor and rearing habitat for juvenile Chinook salmon (Oncorhynchus tshawytscha) that emigrate fromCentral Valley rivers to the Pacific Ocean. The Sacramento-San Joaquin Delta (Delta) (Figure 1) is a migration corridor and rearing habitat for juvenile Chinook salmon (Oncorhynchus tshawytscha) that emigrate from. Chinook salmon abundance in the Delta is a small fraction of historical abundance which once supported a large salmon fishery [1]. Chinook salmon abundance has decreased largely due to anthropogenic factors including decreased river flow during emigration [2], fragmentation and loss of habitat due to dam construction [1], entrainment in water diversion facilities [3], predation by non-native species [4], limited food supply and exposure to contaminants [3]. Within the Central Valley multiple races of Chinook salmon historically thrived. Central Valley fall-run Chinook salmon are listed as a “species of concern” by NOAA Winter-run Chinook are federally listed as an endangered species and spring-run Chinook are listed as threatened.

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