In a March 2020 post, I described the status of the Delta smelt through 2019. This post updates the status with the most recent 2020 information. Delta smelt continue to be absent from the standard long-term surveys and their related indices. However, some Delta smelt were collected in 2020 in selected locations of the Bay-Delta during focused intensive special surveys designed to find remaining survivors. Larval and juvenile Delta smelt were collected in low numbers in the Bay and north Delta (Figure 1). Pre-adult Delta smelt were also collected in summer trawl surveys (Figure 2).
The north Delta habitats where a few Delta smelt persevere continue to be plagued by constant stressful if not lethal water temperatures (Figures 3 and 4).
As I stated in a prior post, Delta smelt would benefit from increased net flows through the north Delta during the spring and summer.
![](https://calsport.org/fisheriesblog/wp-content/uploads/2021/01/image1.png)
Figure 1. Numbers of larval and juvenile Delta smelt collected in the spring Enhanced Delta Smelt Monitoring (EDSM) 20-mm nets. Source.
![](https://calsport.org/fisheriesblog/wp-content/uploads/2021/01/image2.png)
Figure 2. Numbers of pre-adult Delta smelt collected in the summer Enhanced Delta Smelt Monitoring (EDSM) Kodiak trawls. Source.
![](https://calsport.org/fisheriesblog/wp-content/uploads/2021/01/image3.png)
Figure 3. May through September 2020 water temperature and net tidally-filtered flow in the lower ship channel near Rio Vista. Note water temperatures fall 1-2ºC when net flows increase.
![](https://calsport.org/fisheriesblog/wp-content/uploads/2021/01/image4.jpeg)
Figure 4. May through September 2020 water temperature and net tidally-filtered flow in Cache Slough near Rio Vista. Note water temperatures generally fall 1-2ºC when net flows increase.