Science activity

Science activity #54457, updated 3 October 2025

Fit for the Wild: Cultivating Release-Ready Delta Smelt in Impoundments

Description / purpose

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.

Linked science activities

None specified

Activity status

  • 1 Awarded / Initiating (2025)
  • 2 In progress / Ongoing (2025 - 2027)
  • 3 Complete

Funding summary

Total allocated funding: $633,366

Label Value
Contract # or labor code None
Implementing organization University of California - Davis [UC Davis]
Funding organization State Water Contractors [SWC]
Funding Source Not provided
Date of award 2025-07-01
Date of fiscal year-end 2025-06-30
Total award amount $633,366
State type of obligation Not provided
Federal type of obligation Not provided
Reimbursability Not provided
Procurement mechanism Not provided

Location

Subbasins
Delta regions

Geographic tags

None specified

Products and outputs

None provided

Type and context

Lead implementing organization

Partner implementing organizations

None specified

Funding organizations

Funding programs

None specified

Funding sources

None specified