Egg Hatchability and Tolerance of Brook Trout (Salvelinus fontinalis) Fry at Low pH

1977 ◽  
Vol 34 (4) ◽  
pp. 574-579 ◽  
Author(s):  
John R. Trojnar

Hatchability of brook trout (Salvelinus fontinalis) eggs incubated at pH 4.6, 5.0, 5.6 and 8.0 ranged from 76 to 91%. Differential mortality was experienced when subsequent swim-up fry were exposed to a different pH indicating an acclimation effect. This suggests that brook trout fry incubated at lower, but sublethal, pH levels are less likely to experience acid-induced mortality upon emergence than those incubated in spring upwellings. Key words: low pH, brook trout, egg and fry mortality, acclimation, acid precipitation, lake acidification


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.



1976 ◽  
Vol 33 (1) ◽  
pp. 118-123 ◽  
Author(s):  
Raymond Menendez

During an 11-mo period all developmental stages of the brook trout (Salvelinus fontinalis) were continuously exposed to pH levels of 4.5, 5.0, 5.5, 6.0, 6.5, and the control 7.1. The number of viable eggs was reduced significantly at pH 5.0 and to a lesser extent at the higher pH levels. Embryo hatchability was significantly less at all pH levels below 6.5. Growth and survival of alevins was reduced at the lower pH levels. These data indicate that continual exposure to pH values below 6.5 will result in significant reductions in egg hatchability and growth.



1984 ◽  
Vol 41 (12) ◽  
pp. 1774-1780 ◽  
Author(s):  
David W. Rodgers

Juvenile brook trout, Salvelinus fontinalis, were maintained in water of pH 5.3 or 6.5 and calcium concentrations of 5 or 40 mg/L to determine the effects of these factors on fish growth and calcium dynamics. Growth rates varied more than twofold and were significantly reduced by both low ambient calcium concentration and low pH. In contrast, calcium dynamics of the fish were significantly affected by calcium concentration but not pH. Brook trout in low-calcium water retained less labeled dietary calcium and deposited less labeled calcium in axial skeleton and visceral tissues than fish in high-calcium water. Calcium concentrations of the skin and fins were slightly but significantly reduced among fish in low-calcium water, but neither pH nor ambient calcium concentration significantly affected ash content or calcium concentration of axial skeleton and visceral tissues of experimental fish.



1988 ◽  
Vol 45 (9) ◽  
pp. 1563-1574 ◽  
Author(s):  
C. E. Booth ◽  
D. G. McDonald ◽  
B. P. Simons ◽  
C. M. Wood

Adult brook trout (Salvelinus fontinalis) were exposed for up to 11 d to one of a matrix of 18 Al, low pH, and Ca2+ combinations, chosen as representive of acidified softwater environments in the wild. Reduction in water pH led to pH-dependent net losses of Na+ and Cl− exacerbated by the presence of Al in the water and reduced by elevating Ca2+. Any animal losing more than 4% of its total body Na+ over the first 24 h of Al exposure had a greater than 90% likelihood of eventual mortality. Na+ losses arose from inhibition of influx and stimulation of efflux. The inhibition was persistent and pH dependent. Addition of Al to acidified water had a slight further inhibitory effect on Na+ influx and a large stimulatory effect on efflux. The latter was dependent on Al concentration, was the main cause of initial ion losses and mortality, and declined with time in surviving animals. All Al-exposed fish accumulated Al on their gills, but this was apparently mainly surface or subsurface bound, since no internal Al (plasma or liver) could be detected. Nonsurviving fish had substantially higher gill Al levels than survivors.



1993 ◽  
Vol 50 (8) ◽  
pp. 1717-1727 ◽  
Author(s):  
A. Hontela ◽  
J. B. Rasmussen ◽  
K. Lederis ◽  
H. V. Tra ◽  
G. Chevalier

The levels of arginine vasotocin (AVT), an osmoregulatory peptide, were determined by radioimmunoassay in brain tissue of brook trout (Salvelinus fontinalis) of a wide size range (50–380 mm) from softwater Laurentian lakes ranging in pH from 5.0 to 6.9 at different seasons. Multivariate models (ANCOVA) were developed to quantify the relationship between AVT, pH, body size, and season. Brain AVT levels increased with body size, and the allometric slope was highest in the low-pH lakes (pH 5.0-5.5). Although brook trout > 150 mm had higher brain AVT levels at low pH, no significant differences were detected for brook trout < 150 mm. We hypothesize that the sensitivity of brook trout at the parr stage to acid stress may be linked to their inability to mobilize a hormonal response involving AVT. The seasonal variation in brain AVT levels was similar in all the lakes studied, summer levels being the highest. Although this field study revealed that AVT levels depend also on factors other than acid stress (body size and season), our ANCOVA models allow adjustment for the effects of these covariables. Analyses of this type can be used to field test and calibrate biomarkers for use in ecotoxicology.



1990 ◽  
Vol 68 (6) ◽  
pp. 1270-1280 ◽  
Author(s):  
G. L. Lacroix ◽  
D. J. Hood ◽  
C. S. Belfry ◽  
T. G. Rand

Plasma electrolytes and gill [Al] were determined and gill morphology and histology were examined in Atlantic salmon (Salmo salar) parr and brook trout (Salvelinus fontinalis) from feral populations in acidic streams of southwest Nova Scotia. Plasma [Na+] and [Cl−] were lowest in fish from streams with the lowest pH levels, but there were no correlations between plasma [Na+] or [Cl−] and exchangeable [Al] in streams for both species. Gill [Al] increased exponentially with increasing exchangeable [Al] in water, but was less than 100 μg/g dry weight in both species. There were no correlations between plasma [Na+] or [Cl−] and gill [Al] for both species, and plasma [Na+] and [Cl−] were ultimately linked to low pH. Scanning electron microscopy of gills showed normal primary and secondary lamellae, with few signs of fusion or hyperplasia, only a slight amount of mucus, regular chloride cell crypts, and epithelial cells with distinct microridges. Histology of gill sections showed few lesions in the primary lamellae but some focal histologic lesions in the secondary lamellae of greater than 50% of fish, regardless of ambient pH or [Al]. The histopathology included hypertrophy of individual epithelial, mucous, and chloride cells, clubbing of tips of secondary lamellae, and localized epithelial hyperplasia. These features were focal and not comparable to the extensive morphological changes or histologic lesions usually attributed to high [Al] at low pH. Dissolved organic carbon concentrations greater than 5 mg/L in the acidic streams apparently afforded protection against Al effects at concentrations of at least 360 μg total Al/L.



1985 ◽  
Vol 63 (8) ◽  
pp. 1816-1822 ◽  
Author(s):  
William S. Marshall

The opercular epithelium of brook trout, isolated in vitro in Ussing-style membrane chambers, is used to model the effects of acid precipitation on ion balance in fish. The epithelium normally has a low permeability to sodium, chloride, and mannitol, consistent with the barrier function of the skin. Treatment of the outside surface of the epithelium with low pH (threshold pH = 3.9) reversibly reduces transepithelial resistance (Rt). Reduction of outer pH to 3.61 ± 0.05 decreases Rt and increases the efflux of ions (Na+ and Cl−) and uncharged solutes, indicating that the epithelium rapidly and reversibly becomes leaky to solutes. Simultaneous mannitol and ion fluxes indicated that a common pathway, in which the solutes moved in relation to their free solution mobilities, is opened by low pH. The results are best explained by the acid-induced opening of a simple water-filled paracellular pathway. Low pH also altered the shape of nonlinear current-voltage relations, reducing the current density required to effect a reduction in Rt. The results are consistent with a model in which the titration by low pH of Ca2+ away from structural sites in the apical "tight" junctions weakens the intercellular junctions, thus leading to increased paracellular ion permeation. The effect may account in part for increased ion loss that leads to the morbidity of fish in soft-water acidic environments.



1990 ◽  
Vol 47 (8) ◽  
pp. 1641-1648 ◽  
Author(s):  
C G. Ingersoll ◽  
D. D. Gulley ◽  
D. R. Mount ◽  
M. E. Mueller ◽  
J. D. Fernandez ◽  
...  

Two strains of 1 yr-old brook trout were exposed to 14 combinations of pH, aluminum, and calcium during a 28-d experiment. Survival, weight, and gill histology of both strains were affected similarly by pH, aluminum, and calcium exposure. Survival was reduced at inorganic monomeric aluminum concentrations (IA1) of 29 μg/L at pH 5.2 and [Formula: see text] at pH 4.4 and 4.8. Fish weight was reduced with exposure to pH below 4.8 or aluminum concentrations [Formula: see text]. The gills sampled from fish exposed to low pH exhibited lifting of the outer epithelium and hypertrophy (increase in size) of chloride and epithelial cells. The response of gills sampled from fish exposed to low pH and elevated aluminum was more pronounced relative to the low pH exposure alone. In addition to the effects observed in the low pH exposed fish, the gills from fish exposed to both acid and aluminum exhibited vacuolation and degeneration of epithelial and chloride cells and the presence of dense cells. Finally, fish confined in PVC tubes designed to mimic in situ field exposure procedures were more sensitive to the toxic effects of acid and aluminum compared to free-swimming fish. Caution must be taken when extrapolating safe field levels from in situ exposures of caged fish.



1978 ◽  
Vol 35 (8) ◽  
pp. 1084-1088 ◽  
Author(s):  
Wilbur L. Mauck ◽  
Paul M. Mehrle ◽  
Foster L. Mayer

Eyed eggs of brook trout (Salvelinus fontinalis) were exposed to Aroclor® 1254 (0.43–13 μg/L) for 10 d before hatching and the fry for 118 d after hatching. Median hatching time, egg hatchability, and sac fry survival were not affected by Aroclor 1254. At 48 d after hatching, growth was significantly (P < 0.05) decreased by Aroclor 1254 concentrations ≥ 1.5 μg/L, but no significant differences in growth of surviving fry were observed at the end of the 118-d exposure. Mortality occurred in fry exposed to 13 μg/L within 48 d of exposure, and after 118 d of exposure significant mortality occurred in the three highest concentrations. Biochemical constituents in brook trout fry related to growth and development were affected by Aroclor 1254. Hydroxyproline and vitamin C concentrations in sac fry (38 d old) were decreased by ≥ 3.1 μg/L. Backbone development in fry exposed for 118 d was significantly altered. Collagen was significantly decreased in the backbone as was the phosphorous concentration, while the calcium concentration increased. Hydroxyproline concentration in collagen isolated from the backbone was also decreased. The no-effect exposure concentration on backbone composition was < 0.43 μg/L. Whole body residues in fry exposed for 118 d were 40 000 to 47 000 times the concentration in water. Key words: brook trout, Salvelinus fontinalis, Aroclor® 1254, polychlorinated biphenyls, PCB, growth, bone development, vitamin C, collagen



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.



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