Effects of a Parasitic Gut Nematode on Consumption and Growth in Juvenile Rainbow Trout (Salmo gairdneri)

1973 ◽  
Vol 30 (3) ◽  
pp. 443-450 ◽  
Author(s):  
J. I. Hiscox ◽  
R. W. Brocksen
Keyword(s):  
Rainbow Trout ◽  
Food Consumption ◽  
Salmo Gairdneri ◽  
Direct Effects ◽  
Lepomis Cyanellus ◽  
Juvenile Rainbow Trout ◽  
Energy Stores ◽  
Warmwater Fish ◽  
Food Assimilation

A technique was developed for differentially infecting juvenile rainbow trout, Salmo gairdneri, by introduction of the parasitic gut nematode, Bulbodacnitis ampullastoma. Desired infection levels were induced in trout with 80% success. B. ampullastoma affected growth and food consumption of trout in the laboratory. The effects of the parasite were evident at low and high ration levels. At low and starvation ration levels the parasite effected a withdrawal of the energy stores of the fish. At higher ration levels, the direct effects of the parasite were compounded by apparent parasite interference with food assimilation by the fish.B. ampullastoma was directly infective to a warmwater fish, Lepomis cyanellus.

Assessment of the Acute Toxicity, Growth Impairment, and Flesh Tainting Potential of a Bleached Kraft Mill Effluent on Rainbow Trout (Salmo gairdneri)

1977 ◽  
Vol 34 (6) ◽  
pp. 869-878 ◽  
Author(s):  
D. M. Whittle ◽  
K. W. Flood
Keyword(s):  
Rainbow Trout ◽  
Acute Toxicity ◽  
Continuous Flow ◽  
Effluent Treatment ◽  
Salmo Gairdneri ◽  
Freshwater Ecosystem ◽  
Juvenile Rainbow Trout ◽  
Effluent Concentration ◽  
Kraft Mill Effluent ◽  
Kraft Mill

Static and continuous-flow bioassays utilizing juvenile rainbow trout (Salmo gairdneri) were conducted on a northern Ontario bleached kraft mill effluent to assess the range of acute toxicity and related sublethal effects. The acute toxicity of the total mill effluent, as determined by static bioassay procedures, ranged from a 96-h LC50 value of 14–49.0% vol/vol. The results of these bioassays depended on testing methodology and effluent treatment systems employed by the mill when samples were collected. Continuous-flow bioassays conducted on the effluent Produced 96-h LC50 values of 21.8 and 24.8% vol/vol. Growth rate of juvenile rainbow trout (1–2 g) held under continuous-flow conditions for 18 days was significantly reduced at 6% vol/vol effluent concentration (P < 0.05). Flavor of yearling rainbow trout [Formula: see text] exposed to 3% effluent for 48 h was significantly impaired (P < 0.05). This effluent concentration, the lowest level impairing flavor represents approximately 0.12 of the 96-h LC50 derived from continuous-flow bioassays. No significant flavor impairment was detected in fish exposed for 144 h to a 2% effluent concentration Flavor impairment at a 3% vol/vol effluent concentration, the most sensitive sublethal response measured in this study, may also be the most critical response when assessing the economic impact of a kraft mill discharge to a freshwater ecosystem.

Some Toxic Constituents of Chlorination-Stage Effluents from Bleached Kraft Pulp Mills

1981 ◽  
Vol 38 (7) ◽  
pp. 739-743 ◽  
Author(s):  
A. B. McKague
Keyword(s):  
Gas Chromatography ◽  
Rainbow Trout ◽  
Kraft Pulp ◽  
Pulp Mill ◽  
Salmo Gairdneri ◽  
Pulp Mills ◽  
Juvenile Rainbow Trout ◽  
Bleached Kraft Pulp ◽  
Toxic Materials ◽  
Kraft Pulp Mills

Constituents responsible for the toxicity of a sample of bleached kraft chlorination-stage effluent to juvenile rainbow trout (Salmo gairdneri) were investigated. Tetrachlorocatechol, 3,4,5-trichlorocatechol, and 2,6-dichlorohydroquinone were identified and evidence was obtained for the presence of other chlorodihydroxybenzenes in toxic acidic fractions of the sample. Concentrations of 0.46 mg/L 3,4,5-trichloro- and 0.74 mg/L tetrachloro-catechol were estimated in the sample by analytical gas chromatography. Toxic materials in the nonacidic fraction were not identified although the nontoxic dichloromethyl methyl sulfone was isolated.Key words: chlorination-stage effluent, toxicity, pulp mill, chlorocatechols, chlorodihydroxybenzenes

Influence of Photoperiod on Growth of Green Sunfish, Lepomis cyanellus

1965 ◽  
Vol 22 (6) ◽  
pp. 1379-1386 ◽  
Author(s):  
W. L. Gross ◽  
E. W. Roelofs ◽  
P. O. Fromm
Keyword(s):  
Food Consumption ◽  
Conversion Efficiency ◽  
Fish Growth ◽  
Food Conversion ◽  
Lepomis Cyanellus ◽  
Exposed Fish ◽  
Total Length ◽  
Warmwater Fish ◽  
Green Sunfish ◽  
Food Conversion Efficiency

Four 6-week experiments were conducted to evaluate the effect of photoperiod on growth (total length and weight), food consumption, and food conversion efficiency by green sunfish. Fish were held at constant temperatures in light-tight aquaria under four photoperiods (8-hr constant; 16-hr constant; variable, increasing from 8 to 16 hr; and variable, decreasing from 16 to 8 hr).Growth, food consumption, and food conversion efficiency were all influenced by photoperiod. Food consumption varied directly with the amount of light to which fish were exposed. Fish growth and food conversion efficiency were closely correlated and were generally highest in the increasing, lowest in the decreasing, and intermediate in the two constant photoperiods, but higher in the longer daylength. The results suggest that photoperiod influences growth through increasing conversion efficiency and also possibly through stimulating food consumption.Varying daylength exerts a greater influence on fish growth than a constant daylength. Increasing photoperiod stimulates growth and decreasing photoperiod inhibits growth. This result suggests that the lack of growth of warmwater fish in fall when water temperatures and average daylength correspond to those of spring is largely due to the influence of decreasing daylength.

Production and Movement of Juvenile Rainbow Trout (Salmo gairdneri) in a Headwater of Bothwell's Creek, Georgian Bay, Canada

1974 ◽  
Vol 31 (1) ◽  
pp. 117-121 ◽  
Author(s):  
D. Ross Alexander ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Great Lakes ◽  
Annual Production ◽  
Salmo Gairdneri ◽  
Ecological Disturbance ◽  
Georgian Bay ◽  
Juvenile Rainbow Trout ◽  
Total Annual Production ◽  
Calculated Ratio

Within the 21,500 m2 headwater, the standing population of juvenile rainbow trout reached a high of 7.05 g/m2 in October. Production was maximum during August at 1.77 g/m2. Total annual production is calculated at 284.5 kg (13.2 g/m2). Spring emigrants (no less than 4830 fish weighing 69 kg) were age I (91%) and age II. Minimum calculated ratio of production to yield as emigrants was 4.1:1. Comparatively few age 0 fish emigrated during summer. Because of their demonstrated capability to produce juveniles, sensitive headwaters must be preserved from ecological disturbance to assure self-perpetuating rainbow trout populations in the Great Lakes.

Effect of Aroclor 1254 and Mirex on Estradiol-lnduced Vitellogenin Production in Juvenile Rainbow Trout (Salmo gairdneri)

1986 ◽  
Vol 43 (1) ◽  
pp. 169-173 ◽  
Author(s):  
Thomas T. Chen ◽  
P. C. Reid ◽  
R. Van Beneden ◽  
R. A. Sonstegard
Keyword(s):  
Rainbow Trout ◽  
Serum Levels ◽  
Salmo Gairdneri ◽  
Sensitive Assay ◽  
Aroclor 1254 ◽  
Juvenile Rainbow Trout ◽  
17Β Estradiol

A rapid sensitive assay for vitellogenin using rocket immunoelectrophoresis was developed in juvenile rainbow trout (Salmo gairdneri) induced with 17β-estradiol. The assay detected vitellogenin serum levels as low as 0.05 mg/mL. Significant reduction of vitellogenin levels were detected in rainbow trout fed for 6 mo on diets contaminated with Aroclor 1254, Mirex, or a mixture of Aroclor 1254 and Mirex.

scholarly journals Migratory Behaviour of Juvenile Rainbow Trout, Salmo gairdneri, in Outlet and Inlet Streams of Loon Lake, British Columbia

1962 ◽  
Vol 19 (2) ◽  
pp. 201-270 ◽  
Author(s):  
T. G. Northcote
Keyword(s):  
Rainbow Trout ◽  
Water Temperature ◽  
Laboratory Experiments ◽  
Day Length ◽  
Water Current ◽  
Salmo Gairdneri ◽  
Flowing Water ◽  
Juvenile Rainbow Trout ◽  
Outlet Stream ◽  
Downstream Movement

The marked differences in response to water current, exhibited by juvenile rainbow trout migrating into Loon Lake from its outlet and inlet streams, were studied both in the field and in experimental laboratory apparatus. All available evidence argued against genetically discrete outlet and inlet stocks, each maintaining different innate responses to water current. Difference in water temperature between streams was shown, in field and laboratory experiments, to regulate direction of juvenile trout migration through action on behaviour associated with downstream movement, maintenance of position and upstream movement.In laboratory experiments with cool (5 and 10 °C) flowing water, recently emerged fry rarely made contact with the stream bottom in darkness and exhibited much more downstream movement than in warm (> 14 °C) water. In cool streams of the Loon Lake system (daily mean consistently < 13 °C) large numbers of recently emerged fry moved downstream in darkness. Laboratory experiments indicated that combination of cool water (10 °C) and long day length (16 hours) induced downstream movement of fingerlings. In the field, fingerlings moved downstream largely in late spring and summer in cool streams of the Loon Lake system.In laboratory experiments with warm (15 and 20 °C) flowing water, recently emerged fry made frequent contact with the stream bottom in darkness and exhibited much less downstream movement than in cool (10 °C) water. In the warm outlet stream (daily mean in summer usually > 15 °C) recently emerged fry maintained position in darkness. Laboratory experiments suggested that short day length (8 hours) may facilitate maintenance of position exhibited by fingerlings in streams during late autumn and winter.Upstream movement of fry recorded in the field and tested in the laboratory was most pronounced in warm water (> 14 °C). Fingerlings subjected to rapid 5–degree (C) increases in water temperature in an experimental stream exhibited an immediate increase in upstream movement. Upstream movement in summer of large fry and fingerlings occurred only in the warm outlet stream; daily periodicity of upstream movement was positively correlated with sharp rises in water temperature.Evidence examined from four other widely separated stream systems indicated an environmental control of migration in juvenile rainbow trout similar to that demonstrated in the Loon Lake stream system. Possible mechanisms and interaction of factors controlling migratory patterns between and within streams are discussed. Significance of the predominant role played by temperature is considered.

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