Activity response to chlorine in the brook trout, Salvelinus fontinalis (Mitchill)

1972 ◽  
Vol 50 (4) ◽  
pp. 405-410 ◽  
Author(s):  
J. W. T. Dandy
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Initial Increase ◽  
Locomotory Activity ◽  
Activity Response ◽  
Selection Responses

Exposure of brook trout to chlorine evoked changes in activity, ventilation, the "coughing" reflex, and at lethal levels a heavy secretion of mucus. Locomotory activity increased initially and was subsequently depressed. Both responses were seen at 0.35 and 0.08 ppm, but the initial increase was not seen at 0.04 or 0.005 ppm. The initial increase lasted 2 h, whilst the depressant response was still continuing after 7 days at the sublethal level of 0.005 ppm.The results are discussed in relation to the different selection responses to different chlorine concentrations shown in rainbow trout by Sprague and Drury (1969).

Food Specialization By Individual Trout

1972 ◽  
Vol 29 (11) ◽  
pp. 1615-1624 ◽  
Author(s):  
James E. Bryan ◽  
P. A. Larkin
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Stomach Contents ◽  
Cutthroat Trout ◽  
Salmo Gairdneri ◽  
Potential Prey ◽  
Repeated Observation ◽  
Size Growth ◽  
Salmo Clarki

Analyses of stomach contents showed that the kinds of prey eaten by brook trout (Salvelinus fontinalis), cutthroat trout (Salmo clarki), and rainbow trout (Salmo gairdneri) were seldom distributed at random among the individuals. Repeated observation of food eaten by individuals in a stream and ponds showed that prey types were eaten in proportions which were characteristic for an individual.Specialization occurred on several different kinds of prey. Although the degree of specialization was higher during shorter intervals, the data suggested that some specialization persisted for half a year. There were no striking correlations between degree of specialization and other individual properties such as size, growth rate, weight of food, number of food items, previous specialization, or area of recapture.In addition to the observations on trout in relatively undisturbed habitats, a field experiment was conducted using laboratory-reared rainbow trout held in small ponds. The food of each trout in the experiment was sampled repeatedly. In analysis of variance, interaction among the individuals and kinds of prey eaten showed that food specialization occurred. Both the absolute and relative abundance of potential prey were constant during the experiment.

Activity response to oxygen in the brook trout, Salvelinus fontinalis (Mitchill)

1970 ◽  
Vol 48 (5) ◽  
pp. 1067-1072 ◽  
Author(s):  
J. W. T. Dandy
Keyword(s):  
Brook Trout ◽  
Bridge Circuit ◽  
Flow System ◽  
Wheatstone Bridge ◽  
Threshold Concentration ◽  
Response Threshold ◽  
Locomotory Activity ◽  
Absolute Concentration ◽  
Activity Response ◽  
Voltage Output

Locomotory activity of brook trout was measured at 10 °C in water of three different oxygen concentrations. Activity was sensed with a thermistor probe in a Wheatstone bridge circuit. Voltage output of the bridge was integrated automatically and recorded.Exposure to 6.0 and 1.7 p.p.m. oxygen induced tin activity response within minutes which reached a peak during the first hour then slowly waned. The intensity of response was greater to lower than to higher oxygen levels. Not all fish responded to 8.0 p.p.m. The response threshold concentration was estimated to be 8.3 p.p.m. oxygen. The response appeared to be made to the absolute concentration rather than to the rate of oxygen decrease.Various difficulties in estimating thresholds for dissolved substances in a constant flow system are considered. It is suggested that the response threshold found here be applied only in the specific circumstances of this experiment.

Aeromonas salmonicida: Relationship between Extracellular Growth Products and Isolate Virulence

1981 ◽  
Vol 38 (11) ◽  
pp. 1322-1326 ◽  
Author(s):  
Rocco C. Cipriano ◽  
Billy R. Griffin ◽  
Burton C. Lidgerding
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Aeromonas Salmonicida ◽  
Salmo Gairdneri ◽  
Lesion Development ◽  
Culture Supernatants ◽  
Crude Material

Extracellular growth products, extracted from culture supernatants of Aeromonas salmonicida by precipitation with ammonium sulfate and ethanol, were resolved into four fractions by ion-exchange chromatography. Although one of these (fraction II) possessed leukocytolytic activity, virulence of the pathogen was not associated with leukocytotoxicity. A positive correlation was established, however, between virulence and the toxicity of extracted material to cultured rainbow trout gonad (RTG-2) cells. The crude material and fractions II and III from virulent isolates were more toxic to RTG-2 cells than were similar preparations from avirulent isolates. Preparations from virulent isolates caused hemorrhaging, lesion development, and mortality when injected intramuscularly into brook trout (Salvelinus fontinalis) and Atlantic salmon (Salmo solar). Rainbow trout (Salmo gairdneri) were more resistant and lesions could be produced only with fraction II. Fraction II also possessed proteolytic activity.Key words: Aeromonas salmonicida, furunculosis, pathogenicity, salmonids, extracellular products, cytotoxicity, leukocytolysis, proteolysis, fishes

Rainbow trout (Oncorhynchus mykiss) habitat overlap with wild Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) in natural streams: do habitat and landscape factors override competitive interactions?

2018 ◽  
Vol 75 (11) ◽  
pp. 1949-1959
Author(s):  
Scott D. Roloson ◽  
Kyle M. Knysh ◽  
Michael R.S. Coffin ◽  
Karen L. Gormley ◽  
Christina C. Pater ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Atlantic Salmon ◽  
Oncorhynchus Mykiss ◽  
Salmo Salar ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Habitat Overlap ◽  
Atlantic Salmon Salmo Salar ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Natural Streams

The purpose of this study was to update rainbow trout (Oncorhynchus mykiss) invasion status, delineate factors that increase the invasion probability, and quantify habitat overlap between invasive rainbow trout and native Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) on Prince Edward Island, Canada. Analysis of landscape-level variables in 26 watersheds (14 with and 12 without rainbow trout) demonstrated that watershed slope, percent agricultural land use, and distance to the nearest rainbow trout population significantly increased the probability of rainbow trout establishment. Two independent reach-level fish community surveys were conducted by electrofishing in combination with habitat surveys. Reaches with rainbow trout had higher stream slope, Atlantic salmon were found in wider reaches with larger substrate, and brook trout were typically dominant in headwater reaches with finer substrate. Findings at multiple ecological scales illustrated that rainbow trout invasion success is positively influenced by the presence of high-slope habitat. Habitat separation of the three salmonid species indicates that competition with introduced rainbow trout may not be the most significant threat to native salmonid populations.

Models of Ammonia Excretion for Brook Trout (Salvelinus fontinalis) and Rainbow Trout (Salmo gairdneri)

1980 ◽  
Vol 37 (9) ◽  
pp. 1421-1425 ◽  
Author(s):  
Larry J. Paulson
Keyword(s):  
Body Weight ◽  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Ammonia Excretion ◽  
Salmo Gairdneri ◽  
Feeding Rates ◽  
Data Set ◽  
Nitrogen Consumption ◽  
Good Agreement

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

Myxosoma cerebralis: Inactivation of Spores by Hot Smoking of Infected Trout

1982 ◽  
Vol 39 (6) ◽  
pp. 926-928 ◽  
Author(s):  
Ken Wolf ◽  
Maria E. Markiw
Keyword(s):  
Rainbow Trout ◽  
Aquatic Environment ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Soil Samples ◽  
Healthy Tissue ◽  
Salmo Gairdneri ◽  
Heat Inactivation ◽  
Whirling Disease

We processed 2-yr-old rainbow trout (Salmo gairdneri) and brook trout (Salvelinus fontinalis) with clinical whirling disease, which is caused by Myxosoma cerebralis, in one of the following ways: iced, iced and brined, or iced, brined, and hot smoked at 66 °C for 40 min. Skeletal elements of each group were added to tanks containing soil samples from an aquatic environment free of M. cerebralis and aged for 4 mo at 12.5 °C. Following this we assayed for infectivity by holding susceptible rainbow trout fry for 3 mo in the tanks of aquatic soil and skeletal elements. The fry were then examined for M. cerebralis spores. Spores were found in the fry from tanks that had received iced and iced and brined samples, but not in fry from the tanks containing hot smoked tissue, healthy tissue, or no tissue — the last two being negative controls.Key words: whirling disease, Myxosoma cerebralis, heat inactivation, hot smoking

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