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.

--Matt