Avoidance of Low pH in Selection of Spawning Sites by Brook Trout (Salvelinus fontinalis)

1977 ◽  
Vol 34 (11) ◽  
pp. 2210-2215 ◽  
Author(s):  
David W. Johnson ◽  
Dwight A. Webster

Brook trout (Salvelinus fontinalis) show a strong preference for upwelling water in selection of precise spawning sites. Advantage was taken of this behavior in observing discrimination of pH by 48 breeding females. When artificial aquifers delivered ambient (6.7), alkaline (8.0), and acid water (varied at pH 4.0, 4.5 and 5.0 in three trials), females clearly avoided upwellings of pH 4.0 and 4.5 in preference to alkaline and ambient upwelling. Discrimination was not evident at pH 5.0. As natural springs in the Adirondack area are likely to be alkaline, the strong preferences of brook trout for alkaline upwelling water for breeding sites assures a satisfactory environment through egg and larval stages for at least this environmental condition. Key Words: behavior, acidity, brook trout, spawning


1995 ◽  
Vol 52 (8) ◽  
pp. 1733-1740 ◽  
Author(s):  
R. Allen Curry ◽  
David L. G. Noakes

Spawning areas selected by brook trout (Salvelinus fontinalis) displayed variable relationships to discharging groundwater across geologic regions. In Canadian Shield waters, spawning was associated with areas of distinct, discharging groundwater. The specific mechanism of selection could not be determined. Groundwater did not appear to influence the selection of individual redd sites within these discharge areas. Competition among females for the opportunity to spawn in a limited area defined by the discharging groundwater appeared to control the selection of redd sites. In southwestern Ontario streams, discharging groundwater was prominent throughout areas of spawning both at redds and at adjacent, nonspawning substrates (≤7 m). Consequently, relationships between groundwater and spawning site selection were ambiguous. On the unglaciated plateau of central Pennsylvania, no groundwater was observed in redds or nonspawning substrates in streams. Brook trout management programmes must consider these groundwater relationships and therefore the impact of land use on groundwater quality and quantity.



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.



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.



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.



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.



1994 ◽  
Vol 51 (7) ◽  
pp. 1620-1628 ◽  
Author(s):  
Charles J. Gagen ◽  
William E. Sharpe ◽  
Robert F. Carline

Episodes of low pH and high Al concentration were associated with net downstream movement and increased mortality of ratio-tagged brook trout (Salvelinus fontinalis). We compared movements of 10–15 brook trout in two streams with severe acidic episodes with movements of fish in two streams with less severe acidic episodes (reference streams). Study populations moved downstream hundreds of metres in the streams with more severe acidic episodes (pH <5.0 and >200 μg Al/L). Median downstream movement in spring was 250 and 900 m after 20 d for fish in the more acidic streams; one third of the fish were found dead during this time. We found no net movement and no dead fish in the reference streams. Lower stream discharge in fall studies was associated with less severe acidic episodes, less net movement, and no mortality. Water samples collected at individual fish locations indicated that few fish avoided adverse effects of acidic episodes by remaining in microhabitats with higher pH and lower Al concentration.



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