LAUSR

Despite the success of catch-and-release regulations, exposing fish to air during release has emerged as a growing concern over the past two decades. We evaluated the effect of air exposure during midsummer on survival of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri, Bull Trout Salvelinus confluentus, and Rainbow Trout O. mykiss exposed to catch-and-release angling. Fish were sampled by angling on Palisades Creek (August 2016), Sawmill Creek, and the Main Fork of the Little Lost River, Idaho (July−August 2017). After capture, fish were kept underwater while they were measured and individually tagged. Anglers, in groups of two to four, caught study fish and gave them an air exposure treatment of 0, 30, or 60 s. Single-pass backpack electrofishing was then used to recapture tagged fish and estimate relative survival. In total, 328 Yellowstone Cutthroat Trout were sampled (0 s: n = 110; 30 s: n = 110; 60 s: n = 108), 278 Bull Trout (0 s: n = 92; 30 s: n = 94; 60 s: n = 92), and 322 Rainbow Trout (0 s: n = 103; 30 s: n = 106; 60 s: n = 113). The majority of fish were caught using artificial flies (≥92%) and were hooked in the corner of the mouth, lower jaw, or upper jaw (≥78%) in all three species. No difference in survival was observed among air exposure treatments for all three species. Results from the present study along with those from prior field studies of air exposure times during angling suggest that mortality from exposing fish to air for ≤60 s is not likely a population-level concern in catch-and-release fisheries for these species. Catch-and-release angling regulations are one regulatory tool available for fisheries managers (Isermann and Paukert 2010) and are implemented for a variety of reasons such as to prevent the consumption of contaminated fish (Carline et al. 1991), protect species that are easily overexploited (Sullivan 2003), improve the quality of the fishery (Perry et al. 1995; Schneider and Lockwood 2002), and for social reasons (Schill and Scarpella 1997). When *Corresponding author: [email protected] Received January 16, 2018; accepted May 4, 2018 North American Journal of Fisheries Management © 2018 American Fisheries Society ISSN: 0275-5947 print / 1548-8675 online DOI: 10.1002/nafm.10184