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Cardiac Response to Variable Forced Exercise at Different Temperatures: An Angling Simulation for Smallmouth Bass
Author(s) -
Schreer Jason F.,
Cooke Steven J.,
McKinley R. S.
Publication year - 2001
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(2001)130<0783:crtvfe>2.0.co;2
Subject(s) - respirometer , micropterus , zoology , bass (fish) , stroke volume , fishing , biology , heart rate , fishery , chemistry , anatomy , respiration , endocrinology , blood pressure
Longer angling durations (capture by hook and line) and higher water temperatures are generally thought to be more detrimental to angled fish. Here, this concept was investigated in smallmouth bass Micropterus dolomieu by monitoring cardiac output (CO) and its components, heart rate (HR) and stroke volume (SV), before, during, and after a simulated angling event in a Blazka‐type respirometer. Fish (total n = 31) were acclimated to 12, 16, or 20°C and exposed to conditions that elicited repeated burst swimming either briefly (20 s) or to exhaustion (120–180 s). Resting CO and HR increased significantly with increasing temperature ( Q 10 ∼ 2), indicating temperature conformity, whereas SV was not affected by temperature. Recovery times (time after angling until cardiac parameters returned to resting levels) ranged from 0 to 85 min (mean ∼ 40 min) for briefly angled fish and from 20 to 210 min (mean ∼ 105 min) for exhaustively angled fish. These recovery times increased significantly with angling duration but were not affected by water temperature. Almost all of the increase in CO during recovery was attributable to increased HR. At 20°C, the increase in HR was sufficient to result in an increase in CO despite a decrease in SV during the initial portion of recovery. During recovery, both CO and HR increased to approximately 1.8 times and as much as 2.65 times the resting values, whereas SV increased to approximately 1.2 times the resting value. At 20°C, SV typically decreased to 0.8 times the resting value for the initial part of recovery. Recovery intensities (maximum increases in cardiac values) were generally not affected by angling duration. Fish acclimated to 16°C generally had larger recovery intensities than fish at 12°C and 20°C, indicating that for smallmouth bass, 16°C may be an optimal temperature relative to the other two temperatures. From a management perspective, the results suggest that (1) angling duration should be minimized, (2) angling at high as well as low temperatures may be detrimental, and (3) even when fish are angled very quickly, they still undergo a period of increased CO that can last as long as 1 h.