Changes in a Stream Population of Trout Associated with Increased Silt

1965 ◽  
Vol 22 (2) ◽  
pp. 395-404 ◽  
Author(s):  
J.W. Saunders ◽  
M.W. Smith

Low standing crops of brook trout, Salvelinus fontinalis, were closely associated with silting in Ellerslie Brook, Prince Edward Island, and appeared to result from the destruction of hiding places. Spawning was also curtailed by silting. Following scouring, trout stocks soon increased. The remarkable adaptability of trout to silting, in a habitat with favourable flow and water temperature, was illustrated.

1968 ◽  
Vol 25 (11) ◽  
pp. 2443-2451 ◽  
Author(s):  
Kenneth J. Macek

When underyearling brook trout (Salvelinus fontinalis) were fed DDT at a rate of 2.0 mg/kg per week for 31 weeks, they exhibited greater weight gain (43.2 ± 0.8 g) during the period than did untreated fish (36.6 ± 1.1 g). When underyearling fish were fed DDT at different rates for 26 weeks and then starved or fed at a rate equivalent to 10% of the usual feeding rate, the cumulative mortality during this period was 96.2% among fish exposed to 3.0 mg/kg per week, 88.6% among fish exposed to 2.0 mg/kg per week, and 1.2% among untreated fish. Differences in the length of survival of DDT-exposed fish occurred due to dosage, sex, and type of starvation. The evidence suggests that the mortality of DDT-exposed fish was due to the interaction of DDT residues with a combination of environmental stresses, namely starvation, decreasing water temperature, and possibly the physiological stress associated with the spawning season.


1963 ◽  
Vol 20 (2) ◽  
pp. 327-345
Author(s):  
M. W. Smith

A 13-acre pond was formed at head of tide on Wilmot Stream, Prince Edward Island, to hold brook trout (Salvelinus fontinalis) moving between stream and saltwater estuary for greater availability to anglers. Trout continued to move between pond and estuary via an artificial outlet, predominantly during the spring and early summer. Improved angling conditions resulted in capture of 8,215 trout from pond and upper reaches of estuary at rate of 1.2 per rod-hour over three angling seasons. Shallowness of water limited trout-holding capacity of the pond and curtailed better angling success. Other hydrographic conditions and food supply in the pond were favourable for brook trout.


2000 ◽  
Vol 57 (7) ◽  
pp. 1482-1488 ◽  
Author(s):  
Ming Tang ◽  
Daniel Boisclair ◽  
Chantal Ménard ◽  
John A Downing

We performed respirometry experiments to estimate the spontaneous swimming costs of brook trout (Salvelinus fontinalis) for 24 combinations of fish weight (3.5, 17, and 32 g), water temperature (4, 12, and 18°C), and respirometer size (27, 54, and 108 L). Fish swimming characteristics were estimated for each experiment using videocamera recordings and image analysis. Under our experimental conditions, average swimming characteristics of fish, such as swimming speed and turning and acceleration rates, varied from 2.5- to 29-fold. Our data, alone or combined with similar published results on brook trout weighing 1 g, indicated that fish weight was the only variable that could explain a statistically significant proportion of the variations of spontaneous swimming costs for that species (r2 = 0.91). Our work confirms, with a wider range of experimental data, that spontaneous swimming costs of fish are 3- to 22-fold (8-fold average difference) more energy demanding than predicted by forced swimming models developed using fish swimming at constant speeds and directions in flumes.


1995 ◽  
Vol 52 (10) ◽  
pp. 2138-2145 ◽  
Author(s):  
Ming Tang ◽  
Daniel Boisclair

We estimated the cost of spontaneous swimming and the swimming characteristics of juvenile brook trout for 21 combinations of water temperature (3.5, 6, 9, 12, 15, 18, and 20.7 °C) and respirometer volume (27, 54, and 108 L). Spontaneous swimming costs were estimated as the oxygen depletion in the respirometers corrected for biological oxygen demand of the water and standard metabolism of the fish. Spontaneous swimming costs varied 9-fold among our experiments. Swimming characteristics, such as the average and the variance of speed, acceleration, and turning rates, were determined using a pair of video cameras. Swimming characteristics varied 2- to 10-fold among experiments. Speed and turning rate tended to increase with water temperature up to 18 °C and decreased at 20.7 °C. Water temperature (r2 = 0.44) was the only variable that could explain a significant portion of the variations of spontaneous swimming costs between 3.7 and 20.7 °C. Variance of speed (partial R2 = 0.32) and the average turning rate (partial R2 = 0.34) explained 53% of the variation between 3.7 and 18 °C. Average speed never explained more than 35% of spontaneous swimming cost variation.


1959 ◽  
Vol 16 (6) ◽  
pp. 887-895 ◽  
Author(s):  
M. W. Smith

Excellent production of brook trout (Salvelinus fontinalis) and drainage from a stabilized agricultural area are associated in the streams and ponds of Prince Edward Island. Determinations of phosphorus content of Ellerslie Brook, P.E.I., showed major contributions from commercial fertilizers applied to cultivated land. The inference appears valid that commercial land fertilizers are an important factor in maintaining high trout production, and may enhance oyster production in shallow saltwater inlets at the mouths of the streams.


1969 ◽  
Vol 26 (3) ◽  
pp. 695-699 ◽  
Author(s):  
J. W. Saunders

After accidental spillage of the agricultural pesticides nabam and endrin into Mill River, Prince Edward Island, there were extensive mortalities among brook trout (Salvelinus fontinalis (Mitchill)) and juvenile Atlantic salmon (Salmo salar Linnaeus). Surviving trout and salmon showed abnormal behaviour including unseasonal downstream movements in summer and unusual response to an electric field. The abnormal behaviour could provide a useful biological indicator of pollution by the pesticides.


1993 ◽  
Vol 71 (5) ◽  
pp. 972-976 ◽  
Author(s):  
David C. Conley ◽  
Mark A. Curtis

We conducted laboratory experiments to test whether various temperature and photoperiod regimes had any effect on the duration of egg hatching, swimming activity, and copepodid survival in the parasitic copepod Salmincola edwardsii, commonly found on brook trout (Salvelinus fontinalis). Pairs of egg sacs were removed from adult female copepods; one of each pair was exposed to a different photoperiod than the other, at the same temperature. Experiments were conducted at 8, 12, 16, and 20 °C. Temperature had a significant effect on the duration of copepodid swimming activity and survival, and the onset of egg sac hatching was directly related to increasing water temperature. However, hatching duration and hatching success were not affected by temperature over the range tested. Photoperiod had no effect on hatching duration, hatching success, swimming activity, or copepodid survival. Our findings indicate that S. edwardsii copepodids can swim and survive for more than 2 weeks; much longer than the 2 days customarily reported in the literature. This must be accounted for in the development of strategies to control transmission.


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