Ahoy Anadromous Assessors,

'allo all. Here begins this late-week edition of the Sturgeon Detection report. Thanks goes out to Colin Purdy for his correction of my note from Wednesday's mailing. In addition to that erratum of an erratum, there's an addendum to the addendum issued yesterday: I neglected to mention that the plotted White Sturgeon (see website) exclude fish that have only been detected at Lisbon Weir during 2016, but should include all other tags detected multiple times and identified as being implanted in White Sturgeon. This reporting period (Tue 4/5 @ 10:15 AM through Fri 4/8 @ 9:30 AM PST), we detected eight Green Sturgeon (2 new) and six White Sturgeon (all previously detected).

As to the Green Sturgeon detections, all eight were detected moving up the mainstem Sacramento River by our real-time array of 69 kHz receivers. The two detected for the first time in 2016 during this reporting period were both detected at both the Cap. City Fwy. and Tower Bridge emplacements upon entry (Wednesday 4/6 and Thursday 4/7). The Wednesday entrant was also detected Thursday at Knights Landing. GS0461, the Green Sturgeon that was of note earlier this week for being chronologically (and spatially) congruent with a reported Green Sturgeon poaching incident, appears to be alive and well, having been detected at Knights Landing on Wednesday and Colusa earlier today. It had last been heard at Tower Bridge on Tuesday. The remaining five detected Green Sturgeon, all previously reported as last detected at Knights Landing (two 4/3, two 4/4, one 4/5), have since moved upriver, all being detected at Colusa (4/6, 4/6, 4/6, 4/7 and 4/7 resp). Unfortunately, another Green Sturgeon last reported at Knights Landing has disappeared from our pseudo-sonar screens. GS0543, last detected moving upstream at Knights Landing, has been absent from the real-time network since that point in time. I have reached out to the agency that reported the poaching to confirm date and approximate location to see if it's a possibility that GS0543 was the fish poached.

Among the White Sturgeon, two were detected this week at Lisbon Weir in the Yolo Bypass while the four others were swimming downstream in the mainstem of the Sacramento River. Starting from the furthest upstream station, a White Sturgeon heard 4/2 at Colusa was heard again Wednesday 4/6 at Colusa, followed by Knights Landing earlier today. The two detected 3/29 at Tisdale Weir have been detected at Knights Landing (4/5 and 4/6) and the Tower+CCF Bridges (4/7 for both). The White Sturgeon rescued at Tisdale Weir 3/31 (see errata), was detected at the Tower and CCF Bridges on Wednesday in addition after the previously reported detection at Knights Landing (Tuesday 4/4).

See you next week,


From: Colin Purdy
Subj: RE: Real time Sturgeon Detections this week
Date: 2016-04-08 15:08

Thanks Matt. Just a note of interest, we just completed a second fish rescue today at Tisdale Weir and no additional sturgeon were recovered in the apron of the weir. We did rescue 18 adult unclipped Chinook though. Based on run timing we think these are likely natural origin winter or spring-run. Four of these have acoustic tags and all were floy tagged. Genetic samples were collected from all of them.

We think this is likely the last major rescue effort following the high flows last month. We will continue to survey in the Yolo Bypass for stranded sturgeon and will update this group with any additional rescues.

Colin Purdy, M.S.
Supervisor - Valley District/Anadromous Fisheries
CA Department of Fish and Wildlife - North Central Region
1701 Nimbus Rd., Rancho Cordova, CA 95670 I Phone (916) 358-2943 I Fax (916) 358-2912

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