Movement and survival of juvenile fall and spring run Chinook salmon throught the Sacramento-San Joaquin Delta
Introduction:
We will examine the survival and movement patterns of juvenile fall and spring run Chinook salmon (O. tshawytscha) migrating through the Sacramento-San Joaquin Delta and San Francisco Bay, and to the Pacific Ocean. Through the use of acoustic telemetry data, we will be able to reconstruct the migratory pathways of individual fish, and examine how natural and anthropogenic covariates affect reach specific rates/residence time and survival.
Objective:
This study aims to fill in gaps in the lifecycle model for juvenile Central Valley Chinook salmon; particularly fall and spring run Chinook salmon, which until the recent miniaturization of telemetry technology have been difficult to study on such a fine scale. The data gathered from this project will be used to compare the rates of movement, survival, and migratory pathways of fall and spring run smolts through the Sacramento-San Joaquin Delta.
Additionally, laboratory experiments will be conducted regarding the effects of the tags on the potential for tag shedding, tag malfunction/battery life, growth and behavior of the fish.
Methods:
We will implant Juvenile Salmon Acoustic Tracking System (JSATS) tags into the coelom of approximately 200 juvenile fall run and 200 juvenile spring run in each year of our three year study. The tags weigh 0.3 grams in air, allowing us to keep the tag-to-body weight ratio below 5%, and emit a signal every 10 seconds, giving us a projected tag life of approximately 50 days.
The fish will be held for at least 24 hours post surgery to ensure that we are tracking healthy fish. Once the fish are released they will be “recaptured” at each receiver station through the watershed. The fish will be detected on our array of ~75 receivers as they migrate seaward. The receivers have been strategically placed to maximize detection probabilities and to highlight areas of importance (i.e. junctions, diversions, and areas of high mortality).
Progress:
A pilot study was conducted in 2012 with smaller release groups and fewer receivers than the full study. We are currently awaiting the results, but have already gained valuable experience using a new technology that will help us conduct a robust and thorough full-scale study.