Effects of Electroshock, Air Exposure, and Forced Exercise on Swim Performance in Rainbow Trout (Oncorhynchus mykiss)

1994 ◽  
Vol 51 (8) ◽  
pp. 1799-1803 ◽  
Author(s):  
C. J. A. Mitton ◽  
D. G. McDonald
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Intracellular Ph ◽  
Physiological Effects ◽  
Air Exposure ◽  
Swim Performance ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Pulsed Dc ◽  
Identical Fashion

Swim performance of rainbow trout (Oncorhynchus mykiss) following forced exercise and pulsed DC electroshock both with and without subsequent air exposure was examined. Swim stamina was assessed by exercising fish at 39 cm/s until exhausted. Swim performance was impaired following all treatments. Increasing durations of air exposure (0–4 min) after electroshock resulted in progressively prolonged durations of swimming impairment (from 1 to 6 h). Electroshock reduced swimming stamina in a virtually identical fashion to that of 5 min of forced exercise. By comparison with the existing literature on the physiological effects of forced exercise, the impairment of swim performance most likely resulted from a reduction in intracellular pH.

Consequences of Pulsed DC Electrofishing and Air Exposure to Rainbow Trout (Oncorhynchus mykiss)

1994 ◽  
Vol 51 (8) ◽  
pp. 1791-1798 ◽  
Author(s):  
C. J. A. Mitton ◽  
D. G. McDonald
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Additional Stress ◽  
Physical Damage ◽  
Early Recovery ◽  
Air Exposure ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Pulsed Dc ◽  
Fish Collection ◽  
Stimulation Of

Electrofishing, a technique widely used for fish collection, is a procedure that is often followed by handling and air exposure before fish are released. In this study the pathological and physiological consequences of capture with pulsed DC (pDC) electroshock with and without the additional disturbance of air exposure were examined on rainbow trout (Oncorhynchus mykiss). Electroshocked fish showed no evidence of direct mortality, and skeletal damage was only induced under the most severe conditions (~600-g fish, 600 V, 20 or 40 s). Physiological disturbances induced by pDC, in the absence of physical damage, consisted of lactacidosis and stimulation of the interrenal stress response. The acidosis was likely induced by tetany during immobilization and apnea during immobilization and early recovery. In fact, the physiological disturbances induced by pDC were similar in magnitude and duration to 2–3 min of exhaustive exercise and generally more severe than responses previously reported for nonpulsed (i.e., continous) DC gear. In addition, following pDC, fish appeared to experience a mild narcosis, as was evident by a reduced response to the additional stress of air exposure.

Physiological Effects of Brief Air Exposure in Exhaustively Exercised Rainbow Trout (Oncorhynchus mykiss): Implications for "Catch and Release" Fisheries

1992 ◽  
Vol 49 (6) ◽  
pp. 1157-1162 ◽  
Author(s):  
R. A. Ferguson ◽  
B. L. Tufts
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Blood Gases ◽  
Control Fish ◽  
Additional Stress ◽  
Physiological Effects ◽  
Air Exposure ◽  
Catch And Release ◽  
Extracellular Acidosis ◽  
Rainbow Trout Oncorhynchus Mykiss

Rainbow trout (Oncorhynchus mykiss) which were air exposed for 60 s after exhaustive exercise initially had a much larger extracellular acidosis than trout which were only exercised. In both groups, however, plasma pH returned to normal by 4 h. Blood lactate concentrations were also greater in the air-exposed fish and continued to increase throughout the experiment. During air exposure, there was retention of carbon dioxide in the blood, and oxygen tension (Po2) and hemoglobin:oxygen carriage (Hb:O2) both fell by over 80%. After 30 min of recovery, however, blood gases resembled those in fish which were only exercised. Finally, survival after 12 h was 10% in control fish and 88% in the exercised fish but fell to 62 and 28% in fish which were air exposed for 30 and 60 s, respectively, after exercise. These results indicate that the brief period of air exposure which occurs in many "catch and release" fisheries is a significant additional stress which may ultimately influence whether a released fish survives.

Natural and commercial dissolved organic matter protects against the physiological effects of a combined cadmium and copper exposure on rainbow trout (Oncorhynchus mykiss)

1999 ◽  
Vol 56 (3) ◽  
pp. 407-418 ◽  
Author(s):  
Jeff G Richards ◽  
B Kent Burnison ◽  
Richard C Playle
Keyword(s):  
Organic Matter ◽  
Rainbow Trout ◽  
Dissolved Organic Matter ◽  
Oncorhynchus Mykiss ◽  
Computer Modelling ◽  
Plasma Concentrations ◽  
Binding Constants ◽  
Physiological Effects ◽  
Copper Exposure ◽  
Rainbow Trout Oncorhynchus Mykiss

Environmentally realistic concentrations of a natural dissolved organic matter (DOM) (8 mg C/L as dissolved organic carbon (DOC)) protected against the acute respiratory and ionoregulatory effects of 0.2 µM Cd and 0.8 µM Cu on rainbow trout (Oncorhynchus mykiss). The protection afforded by low natural DOC was the same as that afforded by similar or higher concentrations of commercial DOC. Trout exposed to the metals alone experienced large decreases in arterial PO2, increases in arterial PCO2, increases in blood lactate, decreases in plasma concentrations of Cl, and developed pronounced haemoconcentration. There were no deleterious effects of 31 mg C/L commercial DOC on any measured aspect of trout physiology except for an increase in plasma Cl, which was probably due to elevated aqueous Cl concentrations associated with the DOM addition. No concentration of DOC used in the present study prevented Cd from being bound by trout gills, and some of these fish showed hypocalcemia; however, Cu was kept off the gills of trout exposed to metals plus DOM. Computer modelling using metal-gill binding constants simulated well the accumulation of Cd and the lack of Cu accumulation by trout gills in the presence of DOM.

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