Pisces PIs,

First off, matters of erratum and non-telemetric news. First, the error: The Sturgeon rescued 3/31 @ [Tisdale*] Weir, that had not been detected as of the last report, was incorrectly reported as Green. It is a White Sturgeon. Additionally, a boots-on-the-boat note has reached my attention that there were two poaching events, one believed to be of a White and one of a Green Sturgeon in the Yolo Bypass near Fremont Weir on the 4th of this month. The note suggested that the putative Green Sturgeon had an externally visible tag consistent with a prior year (2011?) fish rescue, but none of the known acoustically tagged Green Sturgeon have been detected at Lisbon Weir this year, which would be en route to the Fremont Weir location via their most likely path. There is one Green Sturgeon (designated GS0461) that was heard on our network of realtime receivers on the same day as the reported poaching event that has thusfar not been detected further upstream, but it seems unlikely that this fish was able arrive at Fremont, not to mention access the Yolo Bypass side of the Weir, by the time of the poaching event. It seems likely to me that the reported poached fish was not one of the region's acoustically tagged Green Sturgeon, but may have been tagged with other technology.

Between Friday 4/1 at 9:40 AM and Tuesday 4/5 at 10:15 AM PST, there were detections of ten Green Sturgeon (half new) and fifteen White Sturgeon. None of the White Sturgeon, with the exception of 3/31's rescue, were previously undetected in 2016.

Green Sturgeon detections over the weekend included five newly detected Green Sturgeon. These entered: one 4/2, two on 4/3, and two on 4/4. All were detected at both the Capital City Freeway (CCF) and Tower Bridges on their first day of detection. Other than the previously mentioned GS0461, all were subsequently detected at Knights Landing a day later. Previously reported Green Sturgeon have continued to travel upstream: those last reported at Knights Landing (3/30, 3/30 and 3/31) have since been detected at Colusa (4/4, 4/2 and 4/3 respectively), with the recently rescued Green Sturgeon taking less time than the other 3/30 Knights Landing fish to traverse the reaches between. Additionally, the two Green Sturgeon heard previously at the Tower Bridge on 3/30 have been detected at Knights Landing (4/1 and 4/3).

A slim majority of White Sturgeon appear to be headed downstream, but there was some variability in the behavior of White Sturgeon over the weekend. Of the eight downstream swimmers, one last heard 3/11 at Colusa was detected again there on 4/1 followed by detections at Knights Landing (4/4) and the Tower and CCF Bridges in Sacramento (4/5). Three of five heard last (previously) at Knights Landing (3/29, 3/31 and 3/31) were detected at the CCF+Tower Bridges (4/5, 4/1 and 4/3 respectively based on the fish). All four fish reported last at the Tower Bridge (3/8, 3/14, 3/17, 3/30) were detected over the weekend at the Tower Bridge again before also being detected at the CCF Bridge (4/3, 4/1, 4/2, 4/3 resp. by fish for both bridges). In addition to the upstream movement pattern, we also witnessed some (5) White Sturgeon exhibiting a behavior of holding near the location of their last detection, which I'll sort from furthest upstream. One White Sturgeon detected 3/29 at Colusa was detected again there 4/2. A White Sturgeon heard 3/28 at Knights Landing, continued to be detected there on 4/2 and 4/3. Finally among the holding group, three fish detected at Lisbon Weir (3/20, 3/21, 3/30) continue to hold there (detections 4/3, 4/2, 4/4, resp.) The last movement pattern noted this week will be the upstream moving White Sturgeon (2), which I'll sort from upstream to downstream. One heard 3/29 at Knights Landing was heard 4/2 at Colusa. Our final reporting this week is of the White Sturgeon rescued 3/31, which has moved upstream from Fremont Weir to Knights Landing, as of 4/4.


*Erratum2: This fish, a female White Sturgeon, not a Green Sturgeon, was rescued at Tisdale Weir, not Fremont Weir as was reported in the e-mail version of this report.

From: Matt Pagel
Subj: RE: Real time Sturgeon Detections this week (brief addendum)
Date: 2016-04-07 13:17

Just a brief note:

I have posted three plots of White Sturgeon migration (divided by the month of their first detection) to the CFTC news page at http://cftc.metro.ucdavis.edu/news . They are linked to the April 6th news item. Direct links for the images are as follows:


Much thanks to Lucy Huang, an undergraduate assistant in the Biotelemetry Lab, for doing much of the legwork on these White Sturgeon plots. Also thanks to Eric Chapman for the inspiration for these plots.


From: Colin Purdy
Subj: RE: Real time Sturgeon Detections this week
Date: 2016-04-06 16:03


Thanks again for these detailed updates and apologies for the confusion on metadata. The White Sturgeon rescued on 3/31/16 was rescued from Tisdale Weir, not Freemont. Its observation at Knights Landing suggests to me that it is moving downstream (40 river miles). We believe this was a spawned out female so this downstream behavior seems appropriate.

I am always glad to get reports of fish moving around after being rescued as it shows they survived and our efforts were not in vain.


- Colin

From: Jeff Stuart
Subj: RE: Real time Sturgeon Detections this week
Date: 2016-04-06 18:09

I second Colin's thoughts. Even if the sturgeon did not continue to spawn, successful detections of an "intact" fish means they survived and can "spawn another day"! Good work all.



From: Michael Thomas
Subj: RE: Real time Sturgeon Detections this week
Date: 2016-04-06 23:19

That is correct, it was a spawned out female. Likely moving down.

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