Determinants of Diet of Brook Trout (Salvelinus fontinalis) in a Mountain Stream

1981 ◽  
Vol 38 (2) ◽  
pp. 184-192 ◽  
Author(s):  
J. David Allan
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Mountain Stream ◽  
Invertebrate Drift ◽  
Prey Choice ◽  
Feeding Rates ◽  
Predator Prey ◽  
Numerical Abundance ◽  
June July ◽  
Time Of Feeding

Feeding rates, time of feeding, and prey choice of brook trout (Salvelinus fontinalis) were studied in Cement Creek, Colorado, in 1975–77. On each of five dates from early June to late September, I collected trout at intervals over a 24-h period, along with samples of invertebrate drift and benthos. Although substantial individual variation was observed in time of feeding and prey choice, feeding during the day appeared to predominate. The period of peak feeding shifted from 18:00–22:00 in June–July to earlier hours in August–September. The average number of prey per predator declined over the season and trout relied more heavily on terrestrial forms as aquatic taxa became more rare. The weight of food eaten per day was ~3–4 × the average amount observed per stomach.The numerical abundance of prey in the diet was significantly correlated with abundance of prey in the drift. Except for a few trout which ingested large, rare prey, this was also true for prey composition by biomass. Large taxa tended to be consistently overrepresented in trout diet and small taxa underrepresented. Several prey species shifted from underrepresentation in trout diets to overrepresentation as they grew in size. Abundance and size of prey, along with individual specialization by trout presumably as a result of experience, are suggested as primary determinants of trout diet.Key words: brook trout, Salvelinus fontinalis; stream, predator-prey, aquatic insects

Behavioural and physiological responses of brook trout Salvelinus fontinalis to midwinter flow reduction in a small ice-free mountain stream

2011 ◽  
Vol 79 (3) ◽  
pp. 707-725 ◽  
Author(s):  
A. N. Krimmer ◽  
A. J. Paul ◽  
A. Hontela ◽  
J. B. Rasmussen
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Physiological Responses ◽  
Mountain Stream ◽  
Flow Reduction

Models of Ammonia Excretion for Brook Trout (Salvelinus fontinalis) and Rainbow Trout (Salmo gairdneri)

1980 ◽  
Vol 37 (9) ◽  
pp. 1421-1425 ◽  
Author(s):  
Larry J. Paulson
Keyword(s):  
Body Weight ◽  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Ammonia Excretion ◽  
Salmo Gairdneri ◽  
Feeding Rates ◽  
Data Set ◽  
Nitrogen Consumption ◽  
Good Agreement

Ammonia excretion by brook trout (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri) was measured in relation to nitrogen consumption, body weight (15–154 g for rainbow trout and 50–360 g for brook trout), and temperature (11.2–21.0 °C) under laboratory conditions. Four natural diets, collected from Castle Lake, California, and a commercial pellet diet were fed to the trout in gelatin capsules at feeding rates from 2.5 to 5% body weight∙d−1. Nitrogen consumption was the most important factor influencing ammonia excretion, followed by body weight and temperature. Testing the models with an independent data set revealed good agreement between measured and predicted rates of excretion. The models seem to estimate adequately ammonia excretion by trout in both natural and artificial aquatic systems.Key words: models, ammonia excretion, nitrogen consumption, body weight, temperature, multiple regression, rainbow trout, brook trout

Temporal and spatial variation in the energy intake of a brook trout (Salvelinus fontinalis) population in an Appalachian watershed

2006 ◽  
Vol 63 (12) ◽  
pp. 2675-2686 ◽  
Author(s):  
Ryan M Utz ◽  
Kyle J Hartman
Keyword(s):  
Energy Intake ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Stomach Contents ◽  
Spatial And Temporal Variation ◽  
Feeding Rates ◽  
Temporal And Spatial Variation ◽  
The Mean ◽  
Temporal And Spatial ◽  
Very High

Stream-dwelling salmonids in eastern North America are often restricted to headwater watersheds, where productivity is low and thus feeding conditions are poor. We sought to quantify how energy intake varies with spatial and temporal variation by monitoring feeding rates in multiple sites over the course of two years. Daily rations were calculated for 939 fish by examining stomach contents. Maintenance rations were compared with daily rations using a bioenergetics model. Consumption peaked in spring, dropped substantially in summer, and remained low until the following spring. A minority of fish fed at very high levels during all seasons, elevating the mean consumption of the population. Fish occupying large sites with low trout densities consistently consumed more energy than fish in smaller streams with high trout densities. A direct relationship between trout density and mean consumption was observed during summer, when feeding conditions were poorest. Our findings suggest that within a headwater watershed, larger reaches of streams where fewer trout are found act as important feeding areas and thus may be important habitat for brook trout (Salvelinus fontinalis).

Movement, Growth, and Survival in a Stream Population of Wild Brook Trout (Salvelinus fontinalis) During a Period of Removal of Non-Trout Species

1975 ◽  
Vol 32 (8) ◽  
pp. 1359-1367 ◽  
Author(s):  
William A. Flick ◽  
Dwight A. Webster
Keyword(s):  
Survival Rate ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Slow Growth ◽  
Survival Rates ◽  
Mountain Stream ◽  
Growth And Survival ◽  
Annual Survival ◽  
Adirondack Mountain

No well-defined changes in growth and survival rates of native brook trout (Salvelinus fontinalis) were detected during a 13-yr period when non-trout species were removed from a small Adirondack Mountain stream using fixed traps located throughout the system. The catch of non-trout species was about 124,000 weighing 2000 kg, and of trout, 13,000, weighing 500 kg. Slow growth characterized the population through this time, with mean lengths of 13.2, 17.3, and 21.3 cm at ages I+, II+, and III+, respectively. The weighted annual survival rate for ages II–V was 18%, with most deaths due to natural causes. The most striking observation was virtual cessation of movement of both trout and non-trout species after 7 yr, suggesting that the removal program had an effect on population behavior, even if it was not reflected in an improvement in trout growth.

Relationship between Feeding and Activity Rates for Actively Foraging Juvenile Brook Trout (Salvelinus fontinalis)

1992 ◽  
Vol 49 (12) ◽  
pp. 2566-2573 ◽  
Author(s):  
Daniel Boisclair
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Total Activity ◽  
Energy Allocation ◽  
Energy Losses ◽  
Feeding Rates ◽  
Experimental Protocol ◽  
Total Consumption ◽  
Consumption Rates ◽  
Allocation Patterns

I tested the hypothesis of the existence of a significant positive linear relationship between activity and consumption rates for an actively foraging fish. Within-day variations in activity rates of 0 + brook trout (Salvelinus fontinalis) kept in enclosures were estimated using an underwater videocamera system. Consumption rates at different periods of that day were estimated using the variations of the digestive tract contents. Total consumption rates (i.e. sum of food ingested by all fish) ranged from values close to zero (−1.4 to 0.9; 12:30–24:00) to 12.7 cal/30 min (08:30–09:00). Total activity rates ranged from 0.06 (14:00–14:30) to 2.94 cal/30 min (08:30–09:00). My results indicate that, under specific environmental conditions, activity rates of brook trout are positively related to their feeding rates and, consequently, that the behavior of this actively foraging fish can result in the reduction of the energy losses associated with swimming during nonfeeding periods. My work also permits the development of an experimental protocol to test hypotheses regarding energy allocation patterns between growth, consumption, and activity rates on a multiday basis.

Response of Limnetic Insect Populations of Two Acidic, Fishless Lakes to Liming and Brook Trout (Salvelinus fontinalis)

1989 ◽  
Vol 46 (2) ◽  
pp. 342-351 ◽  
Author(s):  
Richard A. Evans
Keyword(s):  
New York ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Rapid Reduction ◽  
Density Estimates ◽  
Predator Prey ◽  
Fishless Lakes ◽  
Lower Sign ◽  
Insect Populations ◽  
Seasonal Population

Seasonal population density estimates of limnetic insects in two Adirondack (New York) lakes were obtained from horizontal and vertical net tows and benthic sweep net samples over a 3-yr period; 1 yr while the lakes were acidic and fishless, and 2 yr following addition of (calcium carbonate) CaCO3 and the introduction of brook trout (Salvelinus fontinalis). Before treatment, the limnetic insect assemblages in the study lakes resembled those reported from acidic and/or fishless lakes in Sweden and Canada. Maximum densities of dominant taxa were: Notonectidae; 1.5∙m−3; Corixidae; 1.1∙m−3, Graphoderus (Dytiscidae) larvae; 0.27∙m−3; and Chaoborus americanus; 400∙m−3. Within 3 mo after treatment, all limnetic populations were near or below the detection limit (0.01∙m−3). Limnetic densities of notonectids, corixids, and C. americanus were significantly lower (Mann–Whitney U-tests), and benthic densities of Hemiptera and Coleoptera tended to be lower (sign tests) the summer after treatment than the previous summer. Calculated trout predation levels on Hemiptera and C. americanus, and evidence from the literature, strongly suggest that predation was the major cause of reduced limnetic insect populations. The rapid reduction or elimination of these populations indicates considerable instability of the predator–prey relationships of acidic lakes which have been recently limed and stocked with fish.

SUBLETHAL EFFECTS OF CADMIUM ON PREY CHOICE AND CAPTURE EFFICIENCY IN JUVENILE BROOK TROUT (SALVELINUS FONTINALIS)

2005 ◽  
Vol 24 (7) ◽  
pp. 1751 ◽  
Author(s):  
David J. Riddell ◽  
Joseph M. Culp ◽  
Donald J. Baird
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Sublethal Effects ◽  
Capture Efficiency ◽  
Prey Choice
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