Cardiovascular Responses of Largemouth Bass to Exhaustive Exercise and Brief Air Exposure over a Range of Water Temperatures

Abstract

In this study we examined the effects of exhaustive exercise and brief air exposure on the cardiovascular function of largemouth bass Micropterus salmoides at four water temperatures (13, 17, 21, and 25°C). We used Doppler flow probes to monitor cardiac output and its components (i.e., stroke volume and heart rate) while we manually chased fish to exhaustion to simulate angling, exposed them to air for 30 s, and then recorded patterns of recovery. Resting cardiac variables generally increased with increasing water temperature except for stroke volume, which was temperature independent. Fish heart rate became erratic during exercise, and during air exposure fish exhibited severe bradycardia before becoming tachycardic when returned to the water. Maximal change occurred most rapidly for cardiac output (about 5 min). Several minutes later, changes in heart rate (increase) and stroke volume (decrease) simultaneously reached maximal deviations from resting values. Cardiac output and heart rate increased 150–200% relative to resting values despite 50% reductions in stroke volume, suggesting that largemouth bass are primarily frequency modulators. Maximal changes generally increased with water temperature for cardiac output and heart rate but not for stroke volume, resulting in heightened scope for cardiac output and heart rate with increasing water temperature. Recovery patterns were not influenced by water temperature. Cardiac output and heart rate generally returned to predisturbance levels in approximately 135 min, whereas stroke volume recovered more rapidly (about 110 min). Based on these findings, we suggest that largemouth bass exposed to exhaustive exercise and brief air exposure are capable of recovering from handling disturbances in several hours across the range of water temperatures that we examined (13–25°C).

Moving with the beat: heart rate and visceral temperature of free-swimming and feeding bluefin tuna

“…; figures 2 and 5), which is impressive among fishes and vertebrates in general (Butler et al 1992(Butler et al , 2000Cooke et al 2003;Clark et al 2005bClark et al ,c, 2007Clark & Seymour 2006). Entertaining the suggestion that 130 beats min K1 is the maximum f H for T. maccoyii at 198C, and using a Q 10 of 2.3 (from Korsmeyer et al 1997a), the predicted maximum f H of T. maccoyii at 258C would be just above 200 beats min…”

Influence of local adaptation and interstock hybridization on the cardiovascular performance of largemouth bassMicropterus salmoides

“…Detailed descriptions of the surgical procedure are provided elsewhere (Schreer et al, 2001;Cooke et al, 2003b). Briefly, each fish was anaesthetized prior to surgery with 60·p.p.m.…”

“…Fish were allowed to recover from surgery and to acclimate to the tank for at least 18·h (Cooke et al, 2003b). A darkened area covering approximately 30% of the tank provided cover and ensured that the fish were not disturbed by general laboratory activity.…”

“…The experimental tanks were continuously supplied with pond water at either 10 or 20°C. To elicit exercise, fish were chased around the tank by hand (Cooke et al, 2003b) until they reached exhaustion; a standard technique in fish physiology (Kieffer, 2000). At this point the fish would no longer swim and would lose equilibrium.…”

“…clove oil), and a postmortem calibration was conducted to convert Doppler shift (in V) to actual blood flow (ml·min -1 ; Cooke et al, 2003b). The bulbous arteriosus was catheterized with tubing (PE 120) and a constant infusion pump (Harvard Apparatus, South Natick, MA, USA) was used to perfuse anticoagulated blood (2·g sodium oxalate + 0.4·g sodium chloride + 10·ml distilled H 2 O·l -1 pig's blood) through the aorta and partial gill arches to maintain output pressure.…”