Effects of Fishery‐Related Fight Time and Air Exposure on Prespawn Survival and Reproductive Success of Adult Hatchery Steelhead

Abstract

In recent years, increased scrutiny has been placed on the physiological effects of exhaustive exercise and air exposure on caught‐and‐released fish. Steelhead Oncorhynchus mykiss broodstock in the South Fork Clearwater River, Idaho, were collected by anglers during a winter fishery (water temperatures of 2–5°C); this enabled fight and air exposure times to be recorded to determine their influence on prespawn survival and progeny survival to the fry stage in the hatchery. The average fight time during angling was 164 s. Air exposure was measured when anglers landed fish and again during fish transport from the river to the hatchery vehicle; the longest interval of air exposure averaged 23 s during angling and 28 s during transport. Three‐year average prespawn survival was 97.0% for 1,148 angler‐caught fish, compared to 91.9% for 3,325 swim‐in broodstock collected at the hatchery. The top mixed‐effects logistic regression model estimated that the odds of progeny survival increased by 1.027 times with each additional day of the year until an adult fish spawned; this was likely a reflection of peak spawn time in the hatchery. Fight time and air exposure time did not influence progeny survival or prespawn mortality of adult steelhead captured by anglers.

Evaluation of Management Strategies for an Incidental Catch‐and‐Release Steelhead Fishery

“…Additional fishing regulations could be implemented in an attempt to limit catch‐and‐release mortality and generally include gear and fish handling restrictions. However, findings in the literature on the effectiveness of these regulations at meeting targets for catch‐and‐release mortality are mixed and are likely context specific (Nelson et al 2005; Chiaramonte et al 2018; Twardek et al 2018; Whitney et al 2019). Although such regulations may be effective in certain circumstances, they are likely an imprecise tool to meet management objectives compared to the other management strategies evaluated in this study.…”

After the spawn and on the hook: Sea trout Salmo trutta biophysical responses to different components of catch and release in a coastal fishery

“…Many studies of anadromous salmonids and C&R have been performed on fish during their spawning migrations into freshwater, with angling events occurring before reproduction (Havn et al ., 2015; Lennox et al ., 2015; Robinson et al ., 2015; Thorstad et al ., 2007; Twardek et al ., 2019; Whitney et al ., 2019). However, to our knowledge, the impact of angling events on post‐spawn fish has not been studied extensively in S. trutta or other salmonids.…”

Encounter rates and catch‐and‐release mortality of steelhead in the Snake River basin

“…In its ESA section 4(d) rules for steelhead, NMFS noted that research conducted on catch-andrelease mortality of steelhead in the northwestern United States and British Columbia showed an average mortality rate below 5% (National Marine Fisheries Service 2019). A recent study that used angler-caught steelhead for hatchery broodstock found that angling-related mortality was 3% in the Clearwater River (Whitney et al 2019). As such, IDFG uses a conservative 5% catch-and-release mortality rate for wild steelhead in the management of steelhead fisheries (Marshall 2001; Idaho Department of Fish and Game 2010).…”

“…Several studies have assessed the influence of angling on steelhead survival and have found relatively low mortality rates. Whitney et al (2019) evaluated the role of angling-specifically fight time and air exposure-on survival and reproduction of steelhead. Study fish were from an ongoing angler-caught hatchery broodstock program on the South Fork Clearwater River, Idaho.…”

“…A recent study that used angler‐caught steelhead for hatchery broodstock found that angling‐related mortality was 3% in the Clearwater River (Whitney et al. 2019). As such, IDFG uses a conservative 5% catch‐and‐release mortality rate for wild steelhead in the management of steelhead fisheries (Marshall 2001; Idaho Department of Fish and Game 2010).…”