Entrainment Surveys. In 2009, FWP field personnel surveyed approximately 6.5 miles of irrigation ditch on three enrolled properties for entrained grayling (Table 2). No grayling were captured during these surveys (Table 2). Other fish species captured during the surveys include: xxxxx xxxxx Salvelinus fontinalis, brown trout Salmo trutta, burbot Xxxx xxxx, longnose dace Rhinichthys cataractae, rainbow trout Oncorhynchus mykiss, sculpins Cottus bairdi, suckers likely Catostomus commersoni and mountain whitefish Prosopium williamsoni (Table 2). Table 2. Summary of entrainment survey data collected in 2009 by FWP. Date Landowner Source # of Ditches Surveyed Length of Survey (miles) Species Captured
Entrainment Surveys. The Agencies will complete electrofishing or visual surveys of all irrigation ditches on enrolled lands to determine the extent of Arctic grayling entrainment, following the entrainment protocol (Appendix C).
Entrainment Surveys. In 2015, FWP completed entrainment surveys on 7.16 miles of irrigation ditch on 5 enrolled properties (Table 3). A total of 29 Arctic Grayling were captured in one irrigation ditch during entrainment surveys and returned to the Big Hole River. Arctic Grayling were captured during 3 different electrofishing runs in this ditch starting in July and ending in October. All Arctic Grayling captured were 2015 young-of-the-year. Because of the high rate of entrainment in this ditch, FWP will explore screening or other options to reduce or eliminate the loss of Arctic Grayling in this ditch. Other fish species identified during the surveys include: Eastern Xxxxx Xxxxx Salvelinus fontinalis, Brown Trout Salmo trutta, Rainbow Trout Oncorhynchus mykiss, Mountain Whitefish Prosopium williamsoni, Burbot Xxxx xxxx, Longnose Dace Rhinichthys cataractae, Mottled Sculpin Cottus bairdi, Longnose Suckers Catostomus commersoni, and White Suckers Catostomus catostomus. Table 3. FWP electrofishing Entrainment surveys completed in 2014 in the upper Big Hole watershed as part of the Big Hole Arctic Grayling CCAA. Date Source Miles Number of Arctic Grayling rescued 7/10/2015 Big Hole River 0.72 0 7/10/2015 Deep Creek 0.35 0 7/10/2015 Deep Creek 0.29 0 7/10/2015 Deep Creek 0.45 0 7/10/2015 Seymour Creek 0.40 0 7/13/2015 Big Hole River 0.42 10 7/13/2015 North Fork BHR 0.81 0 7/13/2015 North Fork BHR 0.35 0 7/14/2015 Rock Creek 0.71 0 7/14/2015 Big Hole River 0.26 0 7/14/2015 Big Hole River 0.30 0 7/14/2015 Big Hole River 0.27 0 7/15/2015 Big Swamp Creek 0.30 0 7/15/2015 N.B. Big Swamp Creek 0.35 0 7/15/2015 XxXxxxxx Creek 0.34 0 8/21/2015 Big Hole River 0.42 16 10/22/2016 Big Hole River 0.42 3 TOTAL 7.16 29
Entrainment Surveys. No grayling entrainment surveys were conducted in 2023 in the Centennial Valley. Previous surveys in 2017, 2018, and 2021 did not document grayling entrainment. Future entrainment surveys will occur as new SSPs are created.
