Effects of radio-transmitter antenna length on swimming performance of juvenile rainbow trout

2004 ◽  
Vol 13 (4) ◽  
pp. 312-316 ◽  
Author(s):  
K. J. Murchie ◽  
S. J. Cooke ◽  
J. F. Schreer
1998 ◽  
Vol 55 (7) ◽  
pp. 1583-1590 ◽  
Author(s):  
T Ryan Gregory ◽  
Chris M Wood

Variation among individuals in specific growth rate (SGR), feeding, and two measures of swimming performance and their possible interrelationships were investigated in juvenile rainbow trout (Oncorhynchus mykiss) kept in groups on either satiation or half-satiation rations. Maximum sustainable velocity (Ucrit) was measured as an index of aerobic swimming performance and stamina (fatigue time in a fixed-velocity test at 6 body lengths ·s-1) as an index of anaerobic performance. Individual performance in both of these tests was found to be significantly repeatable. Trout fed on half-satiation ration exhibited significantly lower mean values of SGR and body size and higher levels of aggression-related fin damage, but no significant differences in stamina, relative or absolute Ucrit, glycogen content, or plasma cortisol. However, in these fish, there was a significant negative relationship between SGR and relative Ucrit, a significant positive relationship between SGR and stamina, and a significant positive relationship between SGR and total daily meal. None of these relationships were seen in fish fed to satiation. Plasma cortisol and tissue glycogen stores were not related to SGR. These results indicate that under the intensified competition of restricted ration, there are trade-offs between growth, feeding, and different types of swimming performance.


1994 ◽  
Vol 51 (3) ◽  
pp. 536-544 ◽  
Author(s):  
Rod W. Wilson ◽  
Harold L. Bergman ◽  
Chris M. Wood

Juvenile rainbow trout (Oncorhynchus mykiss, 5–13 g) were chronically exposed to sublethal Al (38 μg∙L−1) in acidified soft water (Na+ = 85, Ca2+ = 28 μEq∙L−1, pH 5.2–5.4) for 36 d. Acclimation (increased resistance to challenge with 162 μg Al∙L−1 Al at pH 5.2) occurred after 5 d and was associated with a fourfold increase in gill mucous cell density and reduction in apparent lamellar surface area; initially elevated blood–water diffusion distances returned to normal after 34 d, but the reduction in apparent surface area persisted. Chronic exposure to acid alone (pH 5.2, same water chemistry) caused no morphometric changes but resulted in persistent impairment of Ucrit (critical aerobic swimming speed) by about 10%. This was due to increased oxygen requirements at subcritical swimming speeds (loading stress) and was alleviated when trout were swum at pH 6.5 (zero Al) on day 36. In trout preexposed to sublethal Al, Ucrit was chronically impaired by approximately 16% due to loading stresses and reduction in the maximum rate of oxygen uptake, Mo2max (limiting stress); Ucrit and Mo2max remained depressed even when fish were swum at pH 6.5 (zero Al). Reduced gill area compromises the aerobic scope for activity but may be an unavoidable cost of acclimation to Al.


1997 ◽  
Vol 200 (17) ◽  
pp. 2337-2346 ◽  
Author(s):  
D Alsop ◽  
C Wood

The impacts of feeding on the rate of O2 consumption (O2), aerobic swimming performance, nitrogenous waste excretion (ammonia-N and urea-N) and protein utilization as an aerobic fuel were investigated in juvenile rainbow trout. Feeding trout to satiation (in groups of 120) resulted in rapid growth and elevated routine O2 by 68% relative to fasted fish and by 30% relative to trout fed a maintenance ration of 1% of body mass daily. This in-tank O2 of satiation-fed trout was approximately 70% of the O2max observed at the critical swimming speed (UCrit) when trials were performed on individual trout in swimming respirometers. Feeding increased O2 at all swimming speeds; the absolute elevation (specific dynamic action or SDA effect) was dependent on ration but independent of swimming velocity. There was no difference in O2max at UCrit amongst different ration treatments, but UCrit was significantly reduced by 15% in satiation-fed fish relative to fasted fish. These results suggest that the irreducible SDA load reduces swimming performance and that O2max is limited by the capacity to take up O2 at the gills and/or to deliver O2 through the circulatory system rather than by the capacity to consume O2 at the tissues. Ammonia-N and urea-N excretion increased with protein intake, resulting in a 6.5-fold elevation in absolute protein use and a fourfold elevation in percentage use of protein as an aerobic fuel for routine metabolism in satiation-fed trout (50-70%) relative to fasted fish (15%). Urea-N excretion increased greatly with swimming speed in all treatments, but remained a minor component of overall nitrogen excretion. However, even in satiation-fed fish, ammonia-N excretion remained constant as swimming speed increased, and protein did not become more important as a fuel source during exercise. These results suggest that the reliance on protein as a fuel is greatly dependent on feeding quantity (protein intake) and that protein is not a primary fuel for exercise as suggested by some previous studies.


1994 ◽  
Vol 51 (9) ◽  
pp. 1967-1974 ◽  
Author(s):  
J. A. Johansen ◽  
C. J. Kennedy ◽  
R. M. Sweeting ◽  
A. P. Farrell ◽  
B. A. McKeown

Following either a 24-h (acute) or 25-d (chronic) exposure to tetrachloroguaiacol (TeCG), a component of bleached kraft mill effluent (BKME), juvenile rainbow trout, Oncorhynchus mykiss, were examined for effects on several biochemical parameters, swimming performance, and disease resistance. Acute exposure resulted in increased levels of plasma cortisol and lactate and reductions in liver glycogen and protein, spleen somatic index, leucocrit, hemoglobin, swimming performance, and disease resistance. Chronic exposure resulted in most parameters remaining at control levels with the exception of leucocrit which was elevated, plasma cortisol which decreased, and disease resistance which was impaired. These findings correlate well with a previously proposed classic stress response for mammals and are generally consistent with studies in which fish were exposed to whole BKME. The 96-h LC50 for juvenile rainbow trout exposed to TeCG was estimated at 0.37 mg∙L−1.


1999 ◽  
Vol 56 (3) ◽  
pp. 479-486 ◽  
Author(s):  
T Ryan Gregory ◽  
Chris M Wood

Aerobic swimming performance (critical swimming speed, Ucrit), food consumption per meal (by X-ray radiography), specific growth rate (SGR), haematocrit, and fin condition were monitored in individual juvenile rainbow trout (Oncorhynchus mykiss). The fish were held in groups over a 9-week period and fed daily group rations (dry food) of 2.0, 1.5, 1.0, and 0.5% wet body mass (BM)·day-1. SGR declined and competition increased at lower ration levels, as reflected by greater fin damage, reduced haematocrits and condition factors, and, at 0.5% BM·day-1, a substantial increase in the coefficient of variation among individual meals. Absolute Ucrit also declined at lower ration levels. However, there was no relationship between Ucrit and haematocrit, fin damage, or condition factor in any of the ration groups. A negative correlation was found between Ucrit and SGR in individual trout fed a group ration of 2.0% BM·day-1, but a positive correlation was seen at 0.5% BM·day-1 and no relationship at 1.0 and 1.5% BM·day-1. There was a positive relationship between individual SGR and food consumption only among fish fed a ration of 2.0% BM·day-1. A significant negative relationship between Ucrit and individual food consumption was also found among fish in this ration group.


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