Effects of Long-Term Preexposure to Sublethal Concentrations of Acid and Aluminum on the Ventilatory Response to Aluminum Challenge in Brook Trout (Salvelinus fontinalis)

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.

1988 ◽  
Vol 45 (9) ◽  
pp. 1614-1622 ◽  
Author(s):  
R. L Walker ◽  
C. M. Wood ◽  
H. L. Bergman

Brook trout (Salvelinus fontinalis) (acclimated to pH = 6.5, Ca2+ = 400 μequiv∙L−1), when exposed to acid (pH = 4.8, Ca2+ = 400 μequiv∙L−1) and Al (333 μg∙L−1), responded with a twofold increase in ventilation volume within the first 4 h of the challenge period (100 h). Increased ventilation stroke volume accounted for most of the change in ventilatory response; rate increased slightly. Although ventilation volume returned to prechallenge values by 6 h, coughing (flow reversal) and increased mucus production at the gills were notable throughout the challenge period. There were no significant changes in oxygen consumption or [Formula: see text], but hemoglobin oxygen content (micromoles per gram of hemoglobin) decreased by 20%. Arterial pH decreased as a result of both respiratory and metabolic disturbances. Exposure to acid (pH = 4.8, Ca2+ = 400 μequiv∙L−1) in the absence of Al resulted in similar initial changes in ventilation and blood acid–base status; however, ventilation remained elevated above the prechallenge values throughout the experiment (24 h). The transient increase and subsequent return of ventilation to prechallenge levels in the acid/Al-exposed fish suggests that Al interfered with the mechanism controlling the ventilatory response.


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.


2010 ◽  
Vol 1 (2) ◽  
pp. 146-151 ◽  
Author(s):  
John A. Sweka ◽  
Kyle J. Hartman ◽  
Jonathan M. Niles

Abstract In this study, we resurveyed stream habitat and sampled brook trout Salvelinus fontinalis populations 6 y after large woody debris additions to determine long-term changes in habitat and brook trout populations. In a previous study, we added large woody debris to eight streams in the central Appalachians of West Virginia to determine whether stream habitat could be enhanced and brook trout populations increased following habitat manipulation. The large woody debris additions had no overall effect on stream habitat and brook trout populations by 6 y after the additions. The assumption that a lack of large woody debris is limiting stream habitat and brook trout populations was not supported by our results. In high-gradient streams, habitat complexity may be governed more by the abundance of boulders and large woody debris may have a lesser influence on trout populations.


1968 ◽  
Vol 25 (9) ◽  
pp. 1787-1796 ◽  
Author(s):  
Kenneth J. Macek

When sexually maturing yearling brook trout were fed for 156 days with DDT at rates that evidently caused no mortality, fish fed at the lower dosages produced more mature ova than untreated fish. Those fed at the highest dosage produced fewer mature ova than untreated fish. The size of the male fish at the end of the feeding period tended to increase according to dosage of DDT. In eggs and sac fry obtained from various mating combinations of gametes from the experimental groups, mortality was with one exception higher when at least one of the gametes came from treated fish than when they both came from untreated fish. A major portion of the mortality of sac fry in groups where the eggs came from treated fish occurred during the 15th week of development. This period coincided with the period of maximum, utilization of yolk fat reported to occur in other salmonid fry, and indicated that insecticide residues in the eggs were released at this time and resulted in the observed mortality. The residue concentrations in the fish at the end of the feeding period were similar to those reported for wild fish.


1958 ◽  
Vol 36 (4) ◽  
pp. 479-487 ◽  
Author(s):  
André Gagnon

The relative sensitivity of brook trout fry, salmon fry, and 1- and 2-year-old parrs to known quantities of DDT was studied in hatchery-trough experiments with larger numbers of specimens than were used by previous workers. In troughs, in which part-time water circulation was achieved and DDT used at the rate of 0.5 lb./acre (0.32 p.p.m.), high mortality rates (93–100%) were recorded for salmon fry, trout fry, and 1-year-old parrs. Moreover, it was shown that group susceptibility decreases in the following manner: salmon fry > 1-year-old parrs > trout fry. In another series of experiments, under identical conditions, it was shown that sensitivity in salmon decreases with age. Using salmon fry, in troughs deprived of water circulation, a study was made of the effects of various concentrations of DDT: 0.33, 0.18, 0.072, and 0.036 p.p.m. corresponding to 0.5, 0.25, 0.1, and 0.05 lb. of DDT/acre, respectively. The average lethal dose (L.D. 50) was found to be 0.072 p.p.m. A comparison between two series of experiments shows how mixing of the DDT with water makes the poison more deadly than when used as a DDT–oil solution on the surface of water.


1988 ◽  
Vol 45 (9) ◽  
pp. 1633-1642 ◽  
Author(s):  
D. R. Mount ◽  
J. R. Hockett ◽  
W. A. Gern

Adult brook trout (Salvelinus fontinalis) were exposed for 193 d (previtellogenesis to spawning) to six combinations of acid, Al, and low Ca. Survival and growth were reduced by low pH combined with low Ca concentrations. After 41 d of exposure, fish in ail low pH exposures showed depressed plasma osmolality and Na concentrations, but by day 97 this apparent osmoregulatory stress was compensated for in all but the most severe treatment (pH 4.97, 47 μg inorganic Al/L, 0.5 mg Ca/L). At the observed peak of yolking (day 147), fish exposed to this treatment also had mean concentrations of plasma estradiol, vitellogenin, and Ca of only half control values. Fecundity (eggs per female) was significantly reduced as well, but this reduction was due in part to decreased growth. Despite these abnormalities in ionoregulatory and reproductive physiology, fish in all treatment conditions produced mature eggs. Among fish in stressful conditions, individual variation in growth and physiological parameters appeared to be correlated with osmoregulatory status. We hypothesize that the suite of physiological disturbances observed are linked to osmoregulatory impairment.


2021 ◽  
Author(s):  
Annette Cynthia Maher

Long-term records of the abundance of organisms are needed to detect more progressive changes in their populations as a result of external stressors. Long-term changes in historical Brook Trout


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.


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