Effectiveness of Livewell Additives on Largemouth Bass Survival

Abstract

Livewell conditions during competitive angling events are thought to affect fish mortality. We examined the effects of livewell additives on initial and delayed mortality of largemouth bass Micropterus salmoides. We applied three treatments (salt, ice, or salt and ice) to livewells during tournaments conducted on lakes in Illinois, United States, as well as in laboratory and pond experiments designed to examine the effects of fish size and ambient water temperature on mortality. Fish were collected after tournament weigh-in procedures were completed and monitored for delayed mortality every 24 h for 5 d. Initial mortality did not differ among livewell additives during these field experiments. Although delayed mortality was high (35%), it was not significantly different among livewells that contained salt (56%), ice (48%), ice and salt (40%), and controls (30%). Additives administered during the laboratory experiments, at cool water temperatures, resulted in significantly lower delayed mortalities than those observed during the field experiments when ambient water temperatures were warmer. Initial and delayed mortality did not differ among livewell additives during the laboratory experiments. Larger fish in field experiments had significantly greater delayed mortality than smaller fish in the pond experiments even though initial and delayed mortality did not differ among livewell additives. Our results suggest that fish size and ambient water temperature have a greater influence on delayed mortality observed during competitive angling events than the specific livewell additives studied here.

The Effect of Water Temperature, Angling Time, and Dissolved Oxygen on the Survival of Largemouth Bass Subjected to Simulated Angling and Tournament Handling Procedures

“…; Ostrand et al. ). Because 62 fish (30 for measuring survival and 32 for measuring physiological stress in a companion study conducted concurrently with this study) were used in each trial, we needed a method for simulating the “fight” involved in landing a fish that could be applied equally to groups of fish in successive trials.…”

Use of external Indicators to Evaluate Stress of Largemouth (Micropterus salmoides) and Smallmouth (M. dolomieu) Bass at Tournaments

“…Such collisions can result in dermal and ocular lesions, opening a vector for infections (a potential source of delayed mortality). Additionally, poor water quality and hypoxic conditions in livewells are often contributors to postrelease mortality during tournaments [8,13]. Lamprey wounding was rare in this study (< 2% of fishes), and the majority of fishes exhibiting lamprey wounds were smallmouth bass.…”

“…Lower temperatures during fish hauling resulted in lower levels of stress (lower concentrations of corticosteroids and plasma glucose) post-release [9]. Furthermore, Ostrand et al [13] found that initial physiological disturbance and delayed mortality were both higher when angling was conducted at higher ambient water temperatures. Although some studies found that other factors (e.g.…”

“…Tournament organizers on those days added ice to their holding tanks in an effort to keep them from overheating. However, this practice may do more harm than good [13].…”

“…Stress levels can be influenced by a variety of factors including holding time *Address correspondence to this author at the Center for Earth and Environmental Science, SUNY Plattsburgh, USA; Tel: (860)859-7823; E-mail: galphonsemaynard@gmail.com [9], air exposure [10], livewell conditions [11], fish size [12], and water temperature [13]. Recovery time from physiological stress for a variety of fish species ranges from 8 to 12 hours, depending on post-release conditions [14].…”