Influence of Fenitrothion on Swimming Velocities of Brook Trout (Salvelinus fontinalis)

1974 ◽  
Vol 31 (11) ◽  
pp. 1757-1762 ◽  
Author(s):  
R. H. Peterson

The critical swimming velocities of brook trout (Salvelinus fontinalis) following exposure to 150, 500, and 1500 μg/liter fenitrothion were 100, 83, and 70%, respectively, of the performance of control fish. This represented 35 and 60% decrease in power output, respectively, for the two higher concentrations.At step-test intervals longer than 15 min, the critical velocity (ca 4.5–5 lengths [L]/s) was reasonably constant. At shorter step-test intervals, the critical velocity increased rapidly to exceed 7 L/s at a step-test interval of 30 s. The cruising speed of control fish was estimated at 4.5 L/s.The influence of fenitrothion exposure on swimming speed is related to previous studies on sublethal effects of fenitrothion and to concentrations in streams resulting from insecticide spraying.

1968 ◽  
Vol 25 (12) ◽  
pp. 2643-2649 ◽  
Author(s):  
L. A. McDermott ◽  
A. H. Berst

Preliminary sampling revealed the presence of furunculosis disease in the resident brook trout population of the southern Ontario trout stream used in this study.Two plantings of marked yearling brook trout were made in the study area in 1966; one in the spring, and the other in the fall. The spring planting consisted of 1000 brook trout with a predetermined incidence of furunculosis infection and an equal number of trout with no evidence of infection. The fall planting consisted of 2000 brook trout with a known incidence of furunculosis infection.The stream was electrofished periodically during the 2-year period after the first planting. A total of 445 brook trout (140 of the planted hatchery stock, and 305 resident trout) and 127 fish of associated species were captured and examined for the presence of Aeromonas salmonicida, causative agent of furunculosis.Recovery rates of the "infected" and "noninfected" stocks of brook trout were similar, and there was no evidence of transmission of A. salmonicida from the infected fish to the control fish, nor the resident population of brook trout and other species of fish captured.


1986 ◽  
Vol 43 (10) ◽  
pp. 2048-2050 ◽  
Author(s):  
W. H. Tam ◽  
P. D. Payson ◽  
R. J. J. Roy

Brook trout fry (Salvelinus fontinalis) were exposed to pH 4.66 for various durations up to 141 d and then returned to neutral water. Growth of test fish was in general significantly lower than that of control fish for exposures up to days 45–78. In four of six groups of acid-treated fish, growth eventually recovered and the growth rates were not different from that of control fish. The results suggested that growth inhibition was induced early in the exposure to sublethally low pH and that recovery in the latter phase of the experiment occurred whether pH remained acidic or was readjusted to neutral.


1996 ◽  
Vol 74 (4) ◽  
pp. 587-593 ◽  
Author(s):  
W. H. Tam ◽  
Xiaomin Zhang

Brook trout (Salvelinus fontinalis) were divided into a control group at neutral pH, a food-restricted control (Ph–food control) group at neutral pH, and an acid-stressed (pH 4.15) group, and were maintained under these conditions from August 14 to November 1. The food for the pH–food control group was restricted to simulate the reduced food intake of the acid-stressed fish. Throughout September, oocyte development in the acid-stressed fish was accelerated and the oocytes weighed 36–54% more than those of the pH control fish. By late September these oocytes had reached ovulatory size. Then a shift from predominantly high estrogen to high 17α,20β-dihydroxy-4-pregnen-3-one levels occurred in the circulation. Ovulation followed and by October 19 all acid-stressed trout had ovulated. The same sequence of events occurred significantly later in the pH control fish and ovulation was not complete on November 1. Although their oocytes were larger than those of pH control fish in September, hormonal changes and ovulation in pH–food control fish occurred at the same time as in pH control fish. The results suggest that while the reduced food intake during acid stress might have contributed to accelerated oocyte growth, the full effect of chronic acid exposure was responsible for advancing oocyte development, maturation, and ovulation.


1991 ◽  
Vol 48 (10) ◽  
pp. 2016-2027 ◽  
Author(s):  
M. E. Mueller ◽  
D. A. Sanchez ◽  
H. L. Bergman ◽  
D. G. McDonald ◽  
R. G. Rhem ◽  
...  

Gill samples from juvenile brook trout (Salvelinus fontinalis) acclimated to low-level aluminum at pH 5.2 showed severe damage by day 4, with necrosis and fusion of secondary lamellae and hyperplasia and hypertrophy of mucous cells. Over the following 20 d, there was a continual process of repair with proliferation and hypertrophy of mucous cells. Qualitative analysis of gill samples plus physiology and mortality data collected in a companion study indicated progressive development (by day 10 onward) of increasing acclimation to Al. Quantitative analysis of gill samples on day 13 showed that mucous cell volume density had tripled and mucous cell area had doubled in Al-exposed fish compared with control fish. A lamellar fusion index showed evidence of fusion in Al-exposed fish by day 4 with recovery to nearly control levels by day 13. Physiological disturbances appear to be directly related to the histological changes observed in the gill epithelium. At the cellular level, changes in either mucous cell production and secretion or changes in mucus chemistry contribute, in part, to acclimation to Al.


1991 ◽  
Vol 48 (10) ◽  
pp. 1989-1995 ◽  
Author(s):  
R. L. Walker ◽  
C. M. Wood ◽  
H. L. Bergman

Adult brook trout (Salvelinus fontinalis; 200–300 g) were preexposed for 10 wk to 75 μg Al3+∙L−1, pH = 5.2, in soft water (25 μequiv Ca2+∙L−1) and controls to the same conditions without Al3+. When challenged with a lethal dose of Al3+ (333 μg∙L−1) at the same pH (5.2) and Ca2+ (25 μequiv∙L−1), the control fish demonstrated a twofold increase in ventilation volume and ventilatory stroke volume within the first two hours, an increase in [Formula: see text], and a decrease in pHa and hemoglobin O2 saturation. These effects were not seen in the group chronically preexposed to sublethal Al, indicating that some acclimation had occurred. Although the prechallenge [Formula: see text] and [Formula: see text] were the same in the two groups, the arterial pH, plasma [HCO3−], and hemoglobin O2 saturation of the Al-preexposed fish were significantly below those of the control fish, suggesting that the acclimation was achieved at some cost. Possible mechanisms are discussed.


1986 ◽  
Vol 43 (2) ◽  
pp. 275-280 ◽  
Author(s):  
W. H. Tam ◽  
P. D. Payson

Hatchery-reared brook trout (Salvelinus fontinalis) were maintained in the laboratory at mean pH values of 7.34, 5.56, 5.16, and 4.48 from early February to early December. At pH 4.48, the mean growth rates of males were uniformly lowered during the entire experimental period. Among females, growth was inhibited during the first 5 mo, but their rate of weight gain recovered during the period of rapid oocyte development. At the end of the experiment, the body weights of both male and female fish in pH 5.16 and 4.48 were only 70.70–77.34% of the control fish at pH 7.34. Growth was not affected by exposure to pH 5.56. Rapid oocyte development occurred simultaneously over all pH groups in June, suggesting that the initiation of gametogenesis was not affected over the range of pH tested, the number of eggs produced was significantly correlated to body weight; consequently the number of eggs produced by the smaller pH 5.16–4.48 females was reduced. Ovulation was also significantly delayed in the acidic groups.


1987 ◽  
Vol 44 (3) ◽  
pp. 630-635 ◽  
Author(s):  
W. H. Tam ◽  
L. Birkett ◽  
R. Makaran ◽  
P. D. Payson ◽  
D. K. Whitney ◽  
...  

Brook trout (Salvelinus fontinalis), 1+ yr old, were exposed to pH 4.48 from February to December. Compared with control fish maintained at pH 7.34, acid-stressed fish generally had elevated blood glucose levels. Plasma cortisol concentration, measured only in males, was significantly increased in the acid-treated trout up to July. Although somatic growth decreased by about 30% by the end of the experiment, peritoneal fat was unchanged. During the reproductive season, female plasma levels of oestrogen and vitellogenin were the same at both pH levels. When immature fish were implanted with oestradiol-17β and then maintained for 21 d either in pH 7.34 (control) or 4.48, acid-treated fish again showed increased blood glucose levels. Liver weight increased at both pH levels, but liver glycogen was depleted and plasma vitellogenin was significantly increased by exogenous oesterogen only in control fish. It is postulated that before acclimation occurs, acid stress increases cortisol secretion, diverts nutrients normally used for growth to maintain a high blood sugar level, and affects the liver's ability to metabolize carbohydrates and synthesize vitellogenin.


1973 ◽  
Vol 30 (5) ◽  
pp. 698-701 ◽  
Author(s):  
R. A. Drummond ◽  
W. A. Spoor ◽  
G. F. Olson

Changes in cough frequency, locomotor activity, and feeding behavior of yearling brook trout appeared within 2–24 hr at copper concentrations as low as 6–15 μg/liter. Each of these responses appears to be useful for predicting the concentration range of copper likely to have no long-term effects on the species.


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