Effects of Illumination on Behavior of Wild Brown (Salmo trutta) and Rainbow Trout (Salmo gairdneri) Exposed to Black and White Backgrounds

1973 ◽  
Vol 30 (12) ◽  
pp. 1875-1880 ◽  
Author(s):  
John A. Ritter ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Salmo Trutta ◽  
Salmo Gairdneri ◽  
White Background ◽  
Activity Levels ◽  
Sudden Increase ◽  
Experimental Tank ◽  
Protective Response ◽  
Black And White ◽  
Selection Of

Wild brown (Salmo trutta) and rainbow trout (Salmo gairdneri) placed in a circular tank illuminated at 10−2 lx immediately selected black rather than white background. Preference for black fluctuated with activity during the first 2 hr while both selection of black and activity gradually decreased with habituation over the following 84 hr. A sudden increase in illumination to 200 lx reestablished the strong selection of black which decreased rapidly with rising activity. Selection of black was inversely correlated with activity of the fish and was greater under moving than nonmoving water conditions. Differences in activity levels between rainbow and brown trout caused minor differences in response to background.Temporal preference for black background is interpreted as a protective response to the fright stimuli of initial handling, unfamiliarity with the experimental tank, and sudden increase in illumination. Duration of the response after the sudden increase in illumination was less in brown than rainbow trout. Because of its influence on activity and selection of light or dark backgrounds, light is an important ecological factor for trout.

Influence of Environmental Experience on Response of Yearling Rainbow Trout (Salmo gairdneri) to a Black and White Substrate

1973 ◽  
Vol 30 (11) ◽  
pp. 1740-1742 ◽  
Author(s):  
John A. Ritter ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Prior Experience ◽  
Term Effect ◽  
Salmo Gairdneri ◽  
Experimental Tank ◽  
Environmental Conditioning ◽  
Black And White ◽  
Long Term Effect ◽  
Juvenile Trout

Yearling rainbow trout (Salmo garidneri) selected black substrate regardless of size or rearing experience when first introduced into an experimental tank offering a choice of black or white. Differences in the degree of black selection among the various lots of the same strain during the initial 120 min of exposure, under an illumination of 10−2 lx, were correlated only with the level of swimming activity. By 24 hr, only pond-rearsd fish continued to select black while laboratory-reared fish were randomly distributed over black and white. The continuing wariness of only the pond-reared fish reveals the long-term effect of prior experience on juvenile trout behavior. This finding indicates the possible feasibility of environmental conditioning for wariness in the artificial propagation of hatchery-reared fish for live release.

Effects of background adaptation on the pituitary and plasma concentrations of some pro-opiomelanocortin-related peptides in the rainbow trout (Salmo gairdneri)

1984 ◽  
Vol 101 (3) ◽  
pp. 277-284 ◽  
Author(s):  
K. T. Rodrigues ◽  
J. P. Sumpter
Keyword(s):  
Rainbow Trout ◽  
Time Course ◽  
Plasma Concentrations ◽  
Colour Change ◽  
The Body ◽  
Salmo Gairdneri ◽  
White Background ◽  
Black And White ◽  
Background Adaptation

ABSTRACT Radioimmunoassays for α-MSH, β-MSH, ACTH and endorphin were used to measure pituitary concentrations of these peptides in rainbow trout during adaptation to black and white backgrounds. There was no difference in the pituitary content of any of these peptides between long-term black- and white-adapted trout. Plasma levels of α-MSH immunoreactivity were significantly higher in black-adapted trout than in white-adapted trout. Time-course studies revealed that although the body colour of trout showed an initial rapid adaptation to background colour, this was not paralleled by a corresponding change in plasma α-MSH levels. These only showed significant changes after 7 or more days of background adaptation, when melanophore recruitment or degradation occurred on black or white backgrounds respectively. Intravenous administration of mammalian α-MSH, salmon β-MSH I or antibodies to these peptides did not affect short-term background adaptation. However, long-term administration of mammalian α-MSH via osmotic minipump maintained melanophore numbers in grey-adapted trout transferred to a white background, although this observation was based on only two fish. It is concluded that peptides derived from pro-opiomelanocortin do not appear to be involved in controlling physiological colour change but may be involved in regulating morphological colour change of the rainbow trout. J. Endocr. (1984) 101, 277–284

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.

Bacterial Kidney Disease in Feral Populations of Brook Trout (Salvelinus fontinalis), Brown Trout (Salmo trutta), and Rainbow Trout (Salmo gairdneri)

1979 ◽  
Vol 36 (11) ◽  
pp. 1370-1376 ◽  
Author(s):  
Douglas L. Mitchum ◽  
Loris E. Sherman ◽  
George T. Baxter
Keyword(s):  
Rainbow Trout ◽  
Kidney Disease ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Salmo Gairdneri ◽  
Age Classes ◽  
Bacterial Kidney Disease ◽  
Live Fish ◽  
Brown Trout Salmo Trutta

Incidence and effects of bacterial kidney disease (BKD) were determined in wild, naturally reproducing populations of brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Salmo gairdneri) in a small lake and stream system in southeastern Wyoming, USA where BKD epizootics have been observed since 1972. During 1976, dead fish were collected at three upstream stations, and 60 live fish were collected from each of 11 stations. All fish were necropsied, and virological, bacteriological, and parasitological examinations were conducted by standard methods. An indirect fluorescent antibody technique was used to detect the BKD organism in cultures and kidney tissue smears. Bacterial kidney disease was diagnosed in 100% of the dead brook trout collected. Incidence among live fish ranged from 83% at an upstream station to only 3% at the most downstream location, and was highest in brook trout and lowest in rainbow trout. Two longnose suckers (Catostomus catostomus), the only non-salmonids collected, were found negative for BKD. Clinical signs of infection and the most severe infections were found only in brook trout. Five age-classes of feral brook trout were involved in the epizootics. Since other known pathogens were essentially absent, it is believed that all deaths were due to BKD. Relationships between species susceptibility to BKD, age-classes, water chemistry and water temperatures, and certain ecological conditions are discussed. Key words: bacterial kidney disease, feral trout, epizootics, brook trout, brown trout, rainbow trout

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.

Influence of temperature, water current, illumination, and time on activity and substrate selection in juvenile smallmouth bass (Micropterus dolomieui)

1981 ◽  
Vol 59 (12) ◽  
pp. 2322-2330 ◽  
Author(s):  
Hugh R. MacCrimmon ◽  
William H. Robbins
Keyword(s):  
Water Temperature ◽  
Smallmouth Bass ◽  
Water Current ◽  
Activity Levels ◽  
Substrate Selection ◽  
Black And White ◽  
Micropterus Dolomieui ◽  
Highly Correlated ◽  
Fish Activity ◽  
Selection Of

Behaviour of wild juvenile smallmouth bass, Micropterus dolomieui, in the laboratory was significantly influenced by water temperature, current, and illumination. Activity increased with increasing water temperature and (or) water current. When exposed to black and white substrate, selection of black was inversely dependent on temperature and current, and highly correlated with fish activity (r = 0.995, P < 0.001, inverse cubic relation). Substrate pattern influenced fish activity, aggregation, and social interaction. Activity levels increased with increasing incident illumination whereas selection of black substrate declined, particularly at higher water temperatures. Older juveniles became less active with age and preferred black substrate when available, thereby indicating a developing behavioural pattern which favours survival and energy conservation under natural nursery conditions by the discrete use of available cover.

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