Physiological Responses of Walleyes to Live-Release Angling Tournaments

Killen, Shaun S.; Suski, Cory D.; Morrissey, Michael B.; Dyment, Peter; Furimsky, Marosh; Tufts, Bruce L.

doi:10.1577/m02-164

Cited by 25 publications

(23 citation statements)

References 33 publications

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“…Subsequent research has demonstrated that the effects of individual, sublethal stressors applied in a relatively brief period of time are cumulative (Barton et al 1986; Barton and Schreck 1987;Wedemeyer et al 1990). Walleyes captured in live-release tournaments exhibit changes in physiological parameters associated with elevated activity and cell damage, all of which are indicative of stress (Killen et al 2003(Killen et al , 2006. Barton and Zitzow (1995) found that concentrations of the stress hormone cortisol in juvenile walleyes increased quickly after handling and declined after 3, 6, and 12 h in confinement, but then increased after 24 h. Collectively, this information lends further support to the cumulative-stress hypothesis accounting for posttournament mortality.…”

Section: Discussionmentioning

confidence: 65%

Factors Associated with Mortality of Walleyes and Saugers Caught in Live‐Release Tournaments

Schramm

Vondracek

French

et al. 2010

N American J Fish Manag

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We measured the initial mortality (fish judged nonreleasable at weigh-in), prerelease mortality (fish judged nonreleasable 1-2 h after weigh-in [which includes initial mortality]), and postrelease mortality (fish that died during a 5-d retention in net-pens) in 14 live-release tournaments for walleye Sander vitreus conducted in April-October 2006 and April-July 2007 in lakes and rivers in Michigan, Minnesota, North Dakota, South Dakota, and Wisconsin. Among the 14 events, initial mortality was 0-28%, prerelease mortality was 3-54%, and postrelease mortality was 0-100%; the mortality of reference fish (walleyes !31 cm long that were captured by electrofishing and held in net-pens with tournament-caught walleyes to measure postrelease mortality) was 0-97%. Mortality was generally low in events conducted when water temperatures were below 148C but substantially higher in events when water temperatures were above 188C. The mortality of reference fish suggests that capture by electrofishing and minimal handling when the water temperature exceeds 198C results in high mortality of walleyes that is largely the result of the thermal conditions immediately after capture. Mortality was not related to the size of the tournaments (number of boats), the total number or weight of walleyes weighed in, or the mean number or weight of walleyes weighed in per boat. Mortality was positively related to the depth at which walleyes were caught and the live-well temperature and negatively related to the live-well dissolved oxygen concentration. Surface water temperature was the best predictor of mortality, and models were developed to predict the probability of prerelease and postrelease mortality of 10, 20, and 30% or less of tournament-caught walleyes due to water temperature.

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Section: Discussionmentioning

confidence: 65%

Factors Associated with Mortality of Walleyes and Saugers Caught in Live‐Release Tournaments

Schramm

Vondracek

French

et al. 2010

N American J Fish Manag

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“…We suggest that holding walleye in static cages, where walleye have been observed to exhibit sedentary behavior (Goeman 1991), may increase recovery time and, possibly, mortality. Tournament walleyes have shown elevated postcatch stress levels (e.g., increased plasma cortisol, decreased white muscle energy stores; Killen et al 2003). Most studies examining delayed mortality of walleyes (including our study) collected fish after the stressful period extending from catch through weigh-in.…”

Section: Discussionmentioning

confidence: 92%

Delayed Mortality of Tournament‐Caught Walleyes

Graeb

Shepherd

Willis

et al. 2005

N American J Fish Manag

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We quantified the delayed mortality of walleyes Sander vitreus during three tournaments (April–June 2003) on Lake Francis Case, South Dakota. Weigh‐in procedures (e.g., air exposure of fish during weigh‐in, distance traveled, and so forth) and lake conditions (wind speed and wave height) were also measured to investigate how these factors affected delayed mortality. Delayed mortality was similar for control and tournament fish during the April tournament but increased for tournament fish as lake water temperature increased. Delayed mortality was 0% for control fish, even when tournament fish experienced high mortality; thus, the mortality of tournament fish was attributed to the tournament. Tournament procedures were generally similar for all tournaments, except that anglers traveled farther during later tournaments. The higher mortality experienced by tournament‐caught walleyes during the June tournament was probably due to warmer water temperatures (18–20°C). These results will allow fisheries managers to better predict the effects of delayed mortality on walleyes caught in tournaments.

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“…The physiological stress response induced by gillnet entanglement may be exacerbated by injuries incurred while in the net. The significant increases in plasma LDH and CPK seen in gillnet-entangled turtles are indicative of muscle or tissue damage, as these enzymes may leak from ruptured cells into the blood stream (Aguirre et al 1995, Killen et al 2003, Morrissey et al 2005. Several of the studied turtles incurred soft tissue damage from the nets, as documented during the physical examination, and possible cardiac muscle damage due to struggling and overexertion.…”

Section: Discussionmentioning

confidence: 96%

Blood Biochemistry of Sea Turtles Captured in Gillnets in the Lower Cape Fear River, North Carolina, USA

et al. 2009

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Mortality due to fisheries interactions has been implicated as a contributor to population decline for several species of sea turtle. The incidental capture of sea turtles in the coastal gillnet fisheries of North Carolina, USA, has received much attention in recent years, and mitigation measures to reduce sea turtle mortality due to gillnet entanglement are a high priority for managers and conservationists. Efforts to evaluate effects of gillnet entanglement on sea turtle populations are complicated by the lack of information on health status of turtles released alive from nets and postrelease mortality. We obtained blood samples from green (Chelonia mydas) and Kemp's ridley (Lepidochelys kempii) sea turtles captured in gillnets for 20–240 minutes to assess the impacts of gillnet entanglement on blood biochemistry and physiological status. We measured concentrations of lactate, corticosterone, ions (Na+, K+, Cl‐, P, Ca2+), enzymes (lactate dehydrogenase [LDH], creatine phosphokinase [CPK], aspartate aminotransferase [AST]), protein, and glucose in the blood and also performed physical examinations of turtles to document external indicators of health status (injuries, lethargy, muted reflexes). We evaluated the effects of entanglement time on blood biochemistry and to look for correlations between blood biochemistry and results of the physical examinations. We observed a significant increase in blood lactate, LDH, CPK, phosphorus, and glucose with increased entanglement time. Alterations in blood biochemistry were generally associated with a decline in health status as indicated by results of the physical examination. Although entanglement time plays an important role in determining the health status of sea turtles upon release from a gillnet, our results suggest that factors such as the depth and severity of entanglement may also have an effect on health status of turtles and the probability of postrelease survival. We were unable to set a maximum unattended gillnet soak time to minimize impacts on captured sea turtles, and therefore recommend that fisheries managers continue to enforce the net attendance regulations currently in place in the lower Cape Fear River, North Carolina, during the summer months.

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Physiological Responses of Walleyes to Live-Release Angling Tournaments

Cited by 25 publications

References 33 publications

Factors Associated with Mortality of Walleyes and Saugers Caught in Live‐Release Tournaments

Factors Associated with Mortality of Walleyes and Saugers Caught in Live‐Release Tournaments

Delayed Mortality of Tournament‐Caught Walleyes

Blood Biochemistry of Sea Turtles Captured in Gillnets in the Lower Cape Fear River, North Carolina, USA

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