The Service has determined that the following recommendation will be protective of delta smelt. The projects will continue to implement a 7-day average OMR target of -2,000 cfs, and to maintain the flap gates on the agricultural barriers in the open position.
These actions are needed to protect delta smelt for the following reasons:
1. Delta water temperatures are about 19 degrees C (three station average of Mossdale, Rio Vista and Antioch) which is above the range of peak delta smelt spawning, which is 12-18 degrees C. The peak of spawning has likely passed, although a recent Spring Kodiak trawls caught a few pre-spawned delta smelt, meaning further spawning is possible. Temperatures in the delta remain below the lethal temperature of 25 degrees C.
2. Delta smelt caught at the salvage facilities have continued over the past week:
| Date | Smelt Caught at SWP* | Smelt Caught at CVP* |
|---|---|---|
| 5/20/08 | 22 | 24 |
| 5/21/08 | 8 | 0 |
| 5/22/08 | 42 | 28 |
| 5/23/08 | 52 | 48 |
| 5/24/08 | 24 | 68 |
| 5/25/08 | 66 | 12 |
| 5/26/08 | 38 | 12 |
| Total for week | 252 | 192 |
*All smelt numbers are expanded salvage
A total of 1082 delta smelt (all age ranges) have been salvaged this year.
3. Delta smelt were found in the most recent 20 mm survey (Survey 5, May 12 to May 16) in the central Delta. Delta smelt were found in the Sacramento ship channel and at the confluence, although smelt were also caught in the central Delta on the San Joaquin River and in Old and Middle River at stations 809, 901, 902, 906, and 914. Smelt continue to be within the influence of the pumps in the central and south Delta.
This action is needed to help reduce delta smelt entrainment in the south Delta and to reduce risks as water temperatures are increasing in the south Delta.