Risk of Epibenthic Prey to Predation by Rainbow Trout (Salmo gairdneri)

1973 ◽  
Vol 30 (6) ◽  
pp. 787-797 ◽  
Author(s):  
D. M. Ware
Keyword(s):  
Rainbow Trout ◽  
Prey Size ◽  
Food Resource ◽  
Independent Set ◽  
Equation System ◽  
Benthic Invertebrate ◽  
Salmo Gairdneri ◽  
Food Chains ◽  
Prey System ◽  
Benthic Food

A model is developed to describe the risk of aquatic prey to visual predators in general, and is evaluated with particular reference to rainbow trout (Salmo gairdneri). The equation system uses several principles of visual mechanics to determine predation rates and therefore requires statistics on the physical properties of the food resource, besides the visual acuity and other searching constraints of the predator.Application of the model to an independent set of field data accounted for 47% of the seasonal variation in the occurrence of four benthic invertebrate prey in the diet of trout from Marion Lake, B.C. Considerably better agreement — 70% of the variation — was obtained using a three prey system. Sequential comparisons between the predicted and observed pattern of predation suggest that prey activity, prey exposure, prey density, and prey size are four of the major determinants of prey risk in benthic food chains.

Diel Food Selection by Two Sizes of Rainbow Trout (Salmo gairdneri) in an Experimental Stream

1978 ◽  
Vol 35 (7) ◽  
pp. 971-975 ◽  
Author(s):  
Peter A. Bisson
Keyword(s):  
Rainbow Trout ◽  
Prey Size ◽  
Feeding Activity ◽  
Food Selection ◽  
Salmo Gairdneri ◽  
Invertebrate Drift ◽  
Small Fish ◽  
Drift Density ◽  
Experimental Stream ◽  
Selection Of

The food selected by small (~ 3 g) and large (~ 45 g) hatchery rainbow trout (Salmo gairdneri), studied over a 28-h period, showed that the fish fed selectively, but often on different prey organisms. Feeding activity was highest during daylight hours but was only loosely associated with increases in invertebrate drift density. The majority of large trout exploited adult chironomids on the surface, whereas small trout fed primarily on midwater drift. At night when drift densities were low the limited feeding that took place apparently shifted to bottom foraging. Prey size was the most important factor affecting vulnerability to predation at all hours. Both large and small fish rarely consumed invertebrates < 2 mm long. Selection of larger individuals among certain prey taxa occurred, and in two important groups (Trichoptera and Chironomidae) large trout ate significantly larger prey than did small trout. By being size selective, the trout lost the opportunity to exploit smaller organisms, particularly Collembola, which constituted the bulk of the total drift. Key words: diel habits, drift, predation, rainbow trout, size selection

Predation by Rainbow Trout (Salmo gairdneri): the Influence of Hunger, Prey Density, and Prey Size

1972 ◽  
Vol 29 (8) ◽  
pp. 1193-1201 ◽  
Author(s):  
D. M. Ware
Keyword(s):  
Rainbow Trout ◽  
Feeding Behavior ◽  
Foraging Behavior ◽  
Food Consumption ◽  
Prey Density ◽  
Prey Size ◽  
Salmo Gairdneri ◽  
Critical Rate ◽  
Total Food ◽  
Total Food Consumption

The feeding behavior of rainbow trout (Salmo gairdneri) was investigated by exposing fish to several densities and sizes of prey over a range of four substrates of varying complexity. Within substrate treatments the rate of predation could be stimulated by increasing either prey density, prey size, or predator hunger. Between treatments, however, both the intensity of predation and total food consumption proved to be inversely related to the complexity of the substrate because a number of prey were able to find cover and thus escape detection.The results further indicate that the nature of foraging behavior may be controlled by a critical rate of food capture. If trout did not exceed an average of.058 captures sec,−1 substrate-oriented search proceeded to wane.

Temperature Selection of Rainbow Trout (Salmo gairdneri) Fingerlings in Vertical and Horizontal Gradients

1971 ◽  
Vol 28 (11) ◽  
pp. 1801-1804 ◽  
Author(s):  
R. W. McCauley ◽  
W. L. Pond
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Temperature Preference ◽  
Temperature Selection ◽  
Horizontal Gradients ◽  
Significant Difference ◽  
Preferred Temperatures ◽  
Laboratory Investigations ◽  
Horizontal Temperature Gradients ◽  
Selection Of

Preferred temperatures of underyearling rainbow trout (Salmo gairdneri) were determined in both vertical and horizontal temperature gradients. No statistically significant difference was found between the preferred temperatures by the two different methods. This suggests that the nature of the gradient plays a lesser role than generally believed in laboratory investigations of temperature preference.

scholarly journals The Distribution of 35S-Sulfadiazine and 14G-Trimethoprim in Rainbow Trout, Salmo Gairdneri

1979 ◽  
Vol 20 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Torill Bergsjø ◽  
Inger Nafstad ◽  
Kristian Ingebrigtsen
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri

scholarly journals The Influence of Fear Effect to a Discrete-Time Predator-Prey System with Predator Has Other Food Resource

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 865
Author(s):  
Jialin Chen ◽  
Xiaqing He ◽  
Fengde Chen
Keyword(s):  
Discrete Time ◽  
Food Resource ◽  
Sufficient Conditions ◽  
Iteration Scheme ◽  
Predator Species ◽  
Predator Prey ◽  
Interior Equilibrium ◽  
Fear Effect ◽  
Prey System ◽  
Trivial Equilibrium

A discrete-time predator–prey system incorporating fear effect of the prey with the predator has other food resource is proposed in this paper. The trivial equilibrium and the predator free equilibrium are both unstable. A set of sufficient conditions for the global attractivity of prey free equilibrium and interior equilibrium are established by using iteration scheme and the comparison principle of difference equations. Our study shows that due to the fear of predation, the prey species will be driven to extinction while the predator species tends to be stable since it has other food resource, i.e., the prey free equilibrium may be globally stable under some suitable conditions. Numeric simulations are provided to illustrate the feasibility of the main results.

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