Science activity

The primary objective of this project is to develop alternative rearing methods for the critically endangered Delta Smelt, endemic of the San Francisco Bay Delta (SFBD). Current hatchery practices have struggled to overcome domestication effects in captive-reared fish, resulting in reduced fitness and lower survival rates when released into the wild. Additionally, the resource-intensive nature of Delta Smelt rearing and the associated costs present challenges to scaling up production. While the UC Davis Fish Conservation and Culture Laboratory (FCCL) has made significant strides in producing Delta Smelt for supplementation, meeting long-term population recovery goals will require more efficient and effective rearing methods. This project aims to improve post-release survival rates and overall fish production by exploring more naturalized and cost-effective rearing environments.

To achieve this, we will investigate the use of local impoundments (enclosed natural environments that provide more variable and realistic conditions) compared to traditional hatcheries for increasing Delta Smelt production and fitness. We will rear Delta Smelt in enclosures placed within these impoundments and compare key fitness-determining traits, such as survival, growth, temperature susceptibility, hypoxia tolerance, and antipredator behavior, to those of fish reared under controlled conditions at the FCCL. Additionally, we plan to transfer practices developed in other successful fish supplementation programs (e.g. Razorback Sucker and Rio Grande Silvery Minnow) and develop methods for natural spawning within these impoundments by introducing spawning substrates and closely monitoring spawning activity during the natural season.