Selection by Young Rainbow Trout (Salmo gairdneri) in Simulated Stream Environments For Live and Dead Prey of Different Sizes

1983 ◽  
Vol 40 (10) ◽  
pp. 1745-1749 ◽  
Author(s):  
J. R. Irvine ◽  
T. G. Northcote
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Live Prey ◽  
Feeding Experience ◽  
Wide Range ◽  
Experimental Stream ◽  
Dead Prey

Underyearling rainbow trout (Salmo gairdneri) in experimental stream tanks presented with live and dead prey preferred live prey. Trout fry generally were size selective predators and previous feeding experience did not affect the size of prey consumed. When a wide range of prey sizes was offered, larger trout fry fed upon bigger prey than did smaller fry. Cyclops were underrepresented in trout fry stomachs relative to Daphnia of similar size.

Observations on the life-cycle of the strigeoid trematode, Apatemon (Apatemon) gracilis (Rudolphi, 1819) Szidat, 1928

1976 ◽  
Vol 50 (2) ◽  
pp. 125-132 ◽  
Author(s):  
David Blair
Keyword(s):  
Life Cycle ◽  
Rainbow Trout ◽  
Salmo Trutta ◽  
Fish Host ◽  
The Body ◽  
Salmo Gairdneri ◽  
Stone Loach ◽  
Experimental Conditions ◽  
Pericardial Cavity ◽  
Wide Range

AbstractThe life-cycle of Apatemon (A.) gracilis was completed in the laboratory. The snail host is Lymnaeaperegra (Müller). The cercaria is redescribed from a wide range of material. Metacercariae were found in naturally infected rainbow trout (Salmo gairdneri Richardson), three-spined sticklebacks (Gasterosteus aculeatiis L.) and stone loach (Nemacheilus barbatulus (L.)) from Scotland and in three-spined sticklebacks from Iceland. In trout, most metacercariae were found in the pericardial cavity, in sticklebacks, the eye, and in loach, the body cavity. In infection experiments, cercariae from naturally infected Scottish snails developed in threespined sticklebacks, rainbow trout and brown trout (Salmo trutta L.). Under experimental conditions cercariae did not penetrate stone loach, although this species is naturally infected with A gracilis. The phenomenon of fish host specificity is briefly discussed. Development of the metacercaria is described. Excystation of metacercarial cysts with pepsin and trypsin solutions is unlike that reported for any other digenean; the contents of the cyst appear to be under pressure. In pepsin, layers of the cyst wall peel back from one end. When transferred to trypsin, one pole of the cyst ruptures and the worm is forcibly expelled.

Night Feeding of Brown and Rainbow Trout in an Experimental Stream Channel

1969 ◽  
Vol 26 (12) ◽  
pp. 3275-3278 ◽  
Author(s):  
Thomas M. Jenkins Jr.
Keyword(s):  
Rainbow Trout ◽  
Salmo Trutta ◽  
Salmo Gairdneri ◽  
Mountain Stream ◽  
Stream Channel ◽  
Fish Feeding ◽  
Feeding Tubes ◽  
Night Feeding ◽  
Terrestrial Insects ◽  
Experimental Stream

This study sought to determine if stream-living brown and rainbow trout (Salmo trutta and Salmo gairdneri) will feed on drifting terrestrial insects at night. Groups of fish were confined in segments of a rocky-substrate mountain stream, and marked ants were introduced to the current from observation towers equipped with feeding tubes. After the last introductions of an experiment, the fish were removed and their stomachs were examined for marked ants.Although fish of both species fed at night, they appeared to take a smaller percentage of the ants provided than did day-feeding groups studied for comparison. Fish feeding under bright moonlight and starlight captured introduced ants at about the same rates. The results suggest that trout in the type of stream studied feed or are in feeding readiness at nearly all hours of the day or night, at least in the summer months.

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

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
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