Consequences of catch-and-release angling on the physiology, behaviour and survival of wild steelhead Oncorhynchus mykiss in the Bulkley River, British Columbia

Concerns have been raised regarding the practice of exposing fish to air during catch‐and‐release (C&R) angling. The purpose of this study was to evaluate the effects of air exposure on short‐ and long‐term survival and progeny production of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri. Prespawn adults were sampled at a weir during upstream migration in 2016 and 2017, exposed to a simulated angling event of 102 s, and then exposed to air for a randomly selected duration of 0, 30, or 60 s. An additional control group was added during 2017 in which fish were not exposed to simulated angling or air. In total, 1,519 fish were sampled in 2016, and 744 fish were sampled in 2017. Additionally, age‐0 fish (2016: n = 2,924; 2017: n = 1,492) were collected to evaluate the effects of air exposure on the production of progeny. No effect of angling itself or of angling and air exposure was observed on short‐term (≤60 d posttreatment) or long‐term (>1 year posttreatment) survival of adults, with one exception. During 2016, fish that had been air exposed for 60 s had a statistically higher short‐term survival rate than fish that received no air exposure. Air exposure had no effect on the proportion of fish that successfully spawned. Regression analysis revealed that neither angling nor air exposure affected progeny production. Considering that much of the literature, as well as this study, reports little to no influence of air exposure on salmonid mortality or reproductive success, it seems highly unlikely that air exposure of less than 60 s during C&R angling would have negative population‐level effects.

“…; Twardek et al. ). Unfortunately, much of the existing air exposure literature suffers from limitations that make it difficult to apply the results to wild fish populations.…”

Section: Discussionmentioning

confidence: 98%

“…; Twardek et al. ). White Marlin Kajikia albida captured via angling off the coast of Virginia Beach, Virginia, had a mortality rate of 17% when exposed to air for 1 min (Graves et al.…”

Section: Discussionmentioning

confidence: 98%

“…; Twardek et al. ). Unfortunately, this recommendation fails to acknowledge the limitations of the Richard et al.…”

Section: Discussionmentioning

confidence: 98%

“…The maximum amount of air exposure in experiments has been 30 s (Twardek et al. ), 2 min (Schreer et al. ), 3 min (Suski et al.…”

Section: Discussionmentioning

confidence: 99%

“…Lastly, only a single mortality was reported in steelhead that were captured via angling in the Bulkley River, British Columbia, and exposed to air for up to 30 s (Twardek et al. ).…”

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Effects of Air Exposure During Simulated Catch‐and‐Release Angling on Survival and Fitness of Yellowstone Cutthroat Trout

Roth

Schill

Quist

et al. 2019

Consequences of Fishery Gear Type and Handling Practices on Capture and Release of Wild Steelhead on the Bulkley River

Twardek

Elmer

Beere

et al. 2019

Steelhead Oncorhynchus mykiss are captured and released during spawning migrations by the commercial, subsistence (Indigenous), and recreational fishing sectors, though the consequences of these fisheries interactions on steelhead migration are poorly understood. This study evaluated injury, reflex impairment, behavior, and survival of released wild adult steelhead following capture in the subsistence dip-net, subsistence beach-seine, and recreational angling fisheries of the Bulkley River, British Columbia. Wild steelhead were captured using common handling practices employed in each fishery and were monitored postrelease using radiotelemetry. A greater proportion of steelhead captured by dip net and seine had impaired righting reflexes compared with angled fish, but only fish captured by dip net had notably higher incidence of injury (i.e., net marks, torn fins, flesh wounds, scale loss). Fish captured by dip and seine net had considerably faster peak migration rates (>4,000 m/d) than angled fish (<1,000 m/d), which likely reflects when the steelhead are encountered during their migration in these fisheries (earlier versus later stages). Air exposure (15-74 s) and water temperature (9.2-15.1°C) at the time of capture had significant negative relationships with 24-h fallback behavior (temperature only), intermediate-term (10-20 d after capture) migration rates, and peak migration rates in dip-net-captured steelhead. There were no significant effects of capture duration or fish length on injury, righting reflexes, or migratory behavior. Immediate mortality upon release was rare and occurred in only one fish captured by dip net. The 3-d survival was 88-97% for dip-net-caught steelhead, 96-100% for seine-caught steelhead, and 68-100% for angled steelhead. Despite inherent differences in timing and location between these fisheries, findings suggest that air exposure and water temperature can decrease steelhead migration rates. Fishers should look for opportunities to avoid or minimize these capture and handling conditions when releasing steelhead.

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

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.