Air Exposure, Fight Times, and Deep‐Hooking Rates of Steelhead Caught in Idaho Fisheries

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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.

Section: Discussionsupporting

confidence: 90%

Section: Methodsmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

“…) associated with fight and air exposure times that are typically imposed by actual anglers in real fisheries (Lamansky and Meyer ; Chiaramonte et al. ; Roth et al. ).…”

mentioning

confidence: 99%

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

Whitney

Meyer

McCormick

et al. 2019

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“…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.…”

Section: Discussionmentioning

confidence: 99%

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

McCormick

Dobos

Bowersox

et al. 2021

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Managing fisheries for species of conservation concern, such as steelhead Oncorhynchus mykiss fisheries in Idaho where wild steelhead are incidentally caught and released, requires a tradeoff between providing opportunity for anglers to fish for hatchery-origin steelhead and managing conservation risk for wild steelhead. Understanding population-level effects of catch-and-release fishing is critical for effectively balancing this tradeoff. We used an integrated population model to evaluate population-level effects of incidental catch-and-release mortality on steelhead in Idaho and assessed the effectiveness of alternative management strategies for meeting fishery and population objectives. When simulated catch-and-release mortality or encounter rates were low, fishery, abundance, and conservation risk objectives were easily met by implementing fisheries annually, regardless of adult abundance. However, when simulated catch-and-release mortality rates were high, management strategies that required the population to surpass minimum thresholds for pre-season abundance were more likely to meet goals for minimizing conservation risk but limited fishing opportunity substantially. Results of this study provide managers with a framework that can be used to manage fisheries to meet fishery goals in the form of hatchery steelhead harvest while maintaining sustainable populations and minimizing risk to wild steelhead. The results also suggest that when implemented properly, it is possible to meet fisheries and conservation objectives simultaneously.

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

Lubenau,

Johnson,

Bowersox

et al. 2024

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ObjectiveThe potential influence (i.e., impact rate) of catch‐and‐release fisheries on wild steelhead Oncorhynchus mykiss is poorly understood and is a function of the abundance of wild fish, how many fish are encountered by anglers (i.e., encounter rate), and the mortality of fish that are caught and released. In Idaho, estimates of wild steelhead encounter rates have been derived using the number of wild and hatchery steelhead passing Lower Granite Dam, the number of hatchery steelhead harvested, and the number of hatchery steelhead caught and released. The method includes assumptions that hatchery and wild steelhead have equal encounter rates and catch‐and‐release mortality is 5% for wild steelhead. Here, we investigated wild and hatchery steelhead encounter rates by anglers, estimated catch‐and‐release mortality, and concatenated both aspects to examine how existing recreational steelhead fisheries influence wild steelhead mortality.MethodsWe sampled, tagged, and released 1,251 spawn‐year 2020 (SY2020) and 1,956 spawn‐year 2021 (SY2021) adult steelhead at Lower Granite Dam with T‐bar anchor tags and passive integrated transponder (PIT) tags to estimate steelhead encounter rates and catch‐and‐release mortality. Differences in survival of caught steelhead and those not reported as caught were evaluated using detections at various locations (e.g., PIT arrays, weirs).ResultEstimated encounter rates were 43.7% (95% credible interval; 28.2%, 100.0%) for wild fish and 46.7% (29.6%, 100.0%) for adipose‐clipped fish in SY2020. In SY2021, encounter rates were 47.2% (32.4%, 100.0%) for wild fish and 52.3% (37.1%, 100.0%) for adipose‐clipped fish. Based on detections of caught fish and those not reported as caught, catch‐and‐release mortality of wild steelhead was estimated to be 1.6% (0.0%, 5.2%). Wild steelhead impact rates were 0.7% (0.0%, 2.7%) in SY2020 and 0.7% (0.0%, 2.8%) in SY2021.ConclusionEstimated rates of impact on wild steelhead were consistent and low across years despite major differences in the structure of the fisheries. Our results suggest assuming that encounter rates are equal between hatchery and wild steelhead, and that steelhead catch‐and‐release mortality is 5%, will likely lead to a conservative estimate of the wild steelhead impact occurring from catch‐and‐release fisheries.