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

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.

1998 ◽  
Vol 55 (4) ◽  
pp. 796-805 ◽  
Author(s):  
François Marchand ◽  
Daniel Boisclair

Our objectives were (i) to assess the influence of fish density on the energy allocation pattern of juvenile brook trout (Salvelinus fontinalis) and (ii) to define the mechanism by which this influence occurs. We estimated growth, consumption, and activity rates of brook trout held in 8-m3 enclosures characterized by two different densities (four or eight fish per enclosure; D4 and D8 enclosures, respectively). Eight experiments designed to estimate these variables were performed during a 27-day period. Fish from D4 enclosures ( DELTA W bar = 0.46 g) grew twice as much as those from D8 enclosures ( DELTA W bar = 0.24 g). For any given experiment, consumption rates were not significantly different between the two fish densities (0.434-1.09 g dry ·100 g wet-1 ·day-1). However, fish stocked in D8 enclosures displayed more aggressive behavior, executed 5.5 times more movements, and swam at speeds 13% faster than fish in D4 enclosures. These differences resulted in activity rates fourfold higher in D8 enclosures than in D4 enclosures. Empirical analyses combining our results with published values of growth, consumption, and activity rates supported the hypothesis that competition can have a negative effect on growth through a decrease in consumption rates and an increase in activity costs.


1980 ◽  
Vol 37 (9) ◽  
pp. 1421-1425 ◽  
Author(s):  
Larry J. Paulson

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


2006 ◽  
Vol 63 (12) ◽  
pp. 2675-2686 ◽  
Author(s):  
Ryan M Utz ◽  
Kyle J Hartman

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).


2003 ◽  
Vol 60 (4) ◽  
pp. 401-410 ◽  
Author(s):  
Geneviève R Morinville ◽  
Joseph B Rasmussen

Many salmonids, including brook trout (Salvelinus fontinalis), contain both anadromous (migrant) and nonanadromous (resident) forms within a population (partial migration). Although partial migration is commonly observed, the mechanisms governing the adoption of migration or residency are poorly understood. We used field estimates of fish growth coupled with in situ estimates of food consumption rates to demonstrate that a trade-off exists between the ability to efficiently exploit local environments (resident approach) and the capacity to capitalize from large-scale environmental heterogeneity (migrant approach). We demonstrate that in the year before migration, migrant brook trout have consumption rates 1.4 times higher than those of resident brook trout. However, migrants have lower growth efficiencies (ratio of growth to consumption) than residents, indicating that migrants have higher metabolic costs. Residents and migrants also differed in their stable carbon isotope signatures (δ13C), a time-integrated measure that has been linked to habitat use. Fish muscle δ13C of migrants was depleted by 1 ± 0.1‰ compared with that of residents, and this could not be explained by any biases introduced by the time of sampling or the size of fish sampled. Our findings thus agree with the notion that a link exists between metabolic costs (efficiency) and the adopted life-history strategy.


1981 ◽  
Vol 38 (2) ◽  
pp. 184-192 ◽  
Author(s):  
J. David Allan

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


1999 ◽  
Vol 56 (5) ◽  
pp. 875-887 ◽  
Author(s):  
S Tucker ◽  
J B Rasmussen

Through the 137Cs mass balance method, annual consumption rates were estimated for juvenile Atlantic salmon (Salmo salar) parr and precocious males as well as for brook trout (Salvelinus fontinalis) at four sites in the Ste-Marguerite River system, Québec. With explicit age analysis, consumption rates and growth rates were derived on an individual fish and age-class basis. These represent the first consumption estimates for Atlantic salmon in the wild. Precocious males had consumption rates 1.5 times greater than nonmaturing parr, while Atlantic salmon parr consumption rates were 2.7 times greater than brook trout. There was a strong positive relationship between individual annual consumption and growth rates for Atlantic salmon and brook trout at all sites. Subsequently the concept of field maintenance ration was introduced as the intercept of consumption over growth. Maintenance rations for Atlantic salmon parr ranged from 0.010 to 0.016 g·g-1·day-1 between sites. Brook trout had maintenance rations approximately half those of Atlantic salmon at 0.0059 g·g-1·day-1. Precocious male growth efficiencies were half those of nonmaturing parr despite higher feeding and growth rates. Brook trout growth efficiencies were significantly greater than those of Atlantic salmon parr. The lower growth efficiencies observed for Atlantic salmon are likely due to increased metabolic costs associated with higher activity. On average, Atlantic salmon parr spent 2.4-fold more energy in activity than brook trout. Atlantic salmon precocious males spent 1.7 times more energy in activity than parr.


2001 ◽  
Vol 58 (2) ◽  
pp. 386-393 ◽  
Author(s):  
John A Sweka ◽  
Kyle J Hartman

Brook trout (Salvelinus fontinalis) were held in an artificial stream to observe the influence of turbidity on mean daily consumption and specific growth rates. Treatment turbidity levels ranged from clear (<3.0 nephelometric turbidity units (NTU)) to very turbid water (> 40 NTU). Observed mean daily specific consumption rates were standardized to the mean weight of all brook trout tested. Turbidity had no significant effect on mean daily consumption, but specific growth rates decreased significantly as turbidity increased. Brook trout in turbid water became more active and switched foraging strategies from drift feeding to active searching. This switch was energetically costly and resulted in lower specific growth rates in turbid water as compared with clear water. Bioenergetics simulations were run to compare observed growth with that predicted by the model. Observed growth values fell below those predicted by the model and the difference increased as turbidity increased. Abiotic factors, such as turbidity, which bring about changes in the activity rates of fish, can have implications for the accuracy of predicted growth by bioenergetics models.


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