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ID: 2682
[1.01 MB] Martel (sd) Outmigrants Pear Tree 2023.pdf
Martel, C. [s.d.] Emigrant Surveys and Rotary Screw Trap Operation, Outmigrating Juvenile Salmonid Monitoring in the Trinity River Using Rotary Screw Traps in 2023. Report for the Trinity River Restoration Program (TRRP). Hoopa Valley Tribal Fisheries Department, Hoopa, California. Available: https://www.trrp.net/library/document?id=2682.
Annual abundance of outmigrating salmonids has been identified as a key performance measure of the success of the restoration program being implemented in the Trinity River. The Hoopa Valley Tribal Fisheries Department (HVTFD) has monitored the outmigration of salmonids in the Trinity River since 1997, using rotary screw traps. The primary focus of this monitoring program is to track abundance and trends in abundance of Chinook Salmon Oncorhynchus tshawytscha, Coho Salmon O. kisutch and Rainbow Trout O. mykiss (steelhead) naturally produced between Lewiston Dam, which forms a barrier to upstream migration of anadromous salmonids, and the North Fork of the Trinity River. Salmonid production in this section of river is of primary interest due to the river restoration activities there.
In 2023, HVTFD operated a single eight foot rotary screw trap (RST) in the Trinity River at river kilometer (rkm) 118, about 1 km upstream of the confluence with the North Fork of the Trinity River near the Pear Tree Bar; this RST will be referred to as the Pear Tree rotary screw trap, PTRST. This report describes the methods used, brief description of the results, and plans for the future report. HVTFD operated the PTRST for a total of 33 weeks in 2023 between January 18 to September 1.
The 2023 season was the first year of the Klamath Basin outmigrant monitoring program using data collection tablets and a new cloud-based database for data storage. Data at the PTRST was recorded on paper data sheets and transferred to the tablet and database later. The analysis estimating season long outmigrant Chinook Salmon, Coho Salmon, and steelhead will be conducted the US Fish and Wildlife Service (USFWS) office in Arcata, Ca.
Net catch at the PTRST included 26,418 Chinook Salmon, 168 Coho Salmon, and 478 steelhead. In order to estimate trap efficiency, a mark-recapture study using hatchery produced Chinook Salmon from the Trinity River Hatchery was conducted during the 18 of the last 25 weeks of sampling. Average trap efficiency during that period was 1.34% (SD 1.2%).
First Posted: 2025-03-08 00:01:18
Post Updated: 2025-03-08 00:00:48