Catfish in the South Delta: Investigations into Salmonid Species Interaction

Laura Rudolph , HTI Hydroacoustic Technology, Inc., Seattle, WA
Kevin K. Kumagai , HTI-Vemco USA, Inc., Seattle, WA
Veronica Wunderlich , Biotelemetry and Special Investigations Unit, California Department of Water Resources, Sacramento, CA
As an introduced species to the Sacramento-San Joaquin Delta little is known about the behavior of North American Catfish (Ictaluridae). Catfish are considered omnivorous, and will consume most anything, leading to the question of how catfish feeding behavior influences native fish species survival, like threatened and endangered Pacific salmonids (Oncorhynchus spp.). Using advanced technology, such as acoustic tags and HTI software, researchers observe fine-scale catfish movement in the South Delta including the Old River Corridor, Clifton Court Forebay, and the Tracy Fish Collection Facility. Both predators and juvenile salmon were acoustically tagged. Predators include striped bass (Morone saxatilis), largemouth bass (Micropterus salmoides), and catfish. Catfish movement is graphically displayed in Eonfusion visualization software providing a snapshot of migration and/or feeding behavior in the South Delta. Through the use of these behavioral snapshots, fisheries scientists can learn more about predatory behavior and begin to seek solutions for restoring endangered salmonid populations in the Sacramento-San Joaquin Delta.