Your splendid semi-cyclically supplemented sturgeon summary here. Over the course of the last six days (3/22 @ 10:30 - 3/28 @ 10:30) we detected five Green Sturgeon and fifteen White Sturgeon on the 69 kHz real-time acoustic array. Keeping with the theme of last week's report, four of each type of Sturgeon were detected for the first time in 2016 within this reporting period.

The Green Sturgeon are continuing to percolate upstream, assuming you don't consider "percolate upstream" to be an oxymoron. The previously detected fish was last heard 3/21 at Knights Landing and was detected Friday (3/25) at Colusa. The first of the newly-detected fish entered Wednesday (3/23) at the Cap. City Fwy (CCF) Bridge, was detected at Tower Bridge and Knights Landing before being heard finally at Tisdale Weir Saturday (3/26). A Green Sturgeon arriving Thursday (3/24) at CCF made it up to Tisdale on Sunday (3/27). The third newly detected Green Sturgeon entered Saturday (3/26) and was detected earlier today (3/28) at Knights Landing. The final Green Sturgeon covered in this reporting period was detected earlier today at both the CCF and Tower Bridges, so also appears to be making its upstream run.

As to the White Sturgeon, five were detected at Lisbon Weir (1 new), whereas the other ten (3 new) were detected elsewhere in the system. The new Lisbon Weir arrival was first detected earlier today (3/28). Of the other four Lisbon Weir detections, two were last detected about a week ago and the other two were previously detected about 2 weeks ago, all previously at Lisbon Weir.

Of the mainstem Sacramento River detections of returning White Sturgeon, all except two were detected upstream of their previous reported location. Summarizing these detections from furthest downstream to upstream by previously reported location, two were last detected at Hood (3/3 and 2/5), and these were detected this week at Knights Landing (3/25) and CCF (3/27) respectively. Three fish had been last detected at the Tower Bridge (3/3, 3/21, 3/21), and have now been detected at Knights Landing (3/27, 3/23 3/24 respectively). The 3/24 Knights Landing arrival was additionally detected yesterday at Tisdale Weir. One White Sturgeon not reporting upstream of its last known location was a White Sturgeon which today continued a trend established mid-February of making an approximately once-weekly visit to Tisdale Weir. The final returning White Sturgeon was previously seen 3/18 at Tisdale Weir and was detected Tuesday (3/22) at Knights Landing.

The three new-to-2016 White Sturgeon that were detected in the mainstem of the Sacramento River were each detected at the CCF and Tower Bridges. These events occurred 3/24, 3/27 and 3/27.

Overtopping at Tisdale and Fremont Weirs has now ceased. Tisdale, which had been overtopping since March 7th, dropped below the Weir level at approximately 1AM today. Fremont Weir was overtopping starting last Monday and ending late Thursday (3/24). As the water levels continue to retreat and no longer occupy vast floodplains in the bypasses below the weirs, the incidence of fish stranding events may increase.

Logistics time: I now have a web archive of the 2016 Sturgeon detection updates available at . I will (today or tomorrow) post tabular versions of these reports, along with any appropriate attachments, linked from the indicated page. I will have some White Sturgeon related plots to share later today, which will be linked to today's entry.

Thank you,

From: Colin Purdy
Subj: RE: Real time Sturgeon Detections this week
Date: 2016-03-29 15:48

Please keep an ear out for a previously undetected green sturgeon in the Sacramento River. It was rescued and released today from the east side of the Freemont Weir. I'm hoping Marc will follow up this email with the tag code. I would like to know if this fish continues its upstream migration.

We plan to go back out to Freemont Weir and rescue another green sturgeon from the west side of the weir on Monday and will follow that up with a rescue at Tisdale Weir on Tuesday. My staff confirmed today at least three sturgeon are currently stranded out at Tisdale Weir. We need to let water levels drop at both locations before we can safely crowd and rescue these sturgeon.


- Colin

Matthew D. Pagel
Database Manager
Core Array: California Fish Tracking Consortium
Biotelemetry Lab
University of California, Davis