Role of Exposure Duration in Hydrogen Ion Toxicity to Brook (Salvelinus fontinalis) and Rainbow Trout (Salmo gairdneri)

1989 ◽  
Vol 46 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Lawrence R. Curtis ◽  
Wayne K. Seim ◽  
Lisbeth K. Siddens ◽  
Debra A. Meager ◽  
Richard A. Carchman ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Exposure Duration ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Recovery Period ◽  
Whole Body ◽  
Toxicity Tests ◽  
Salmo Gairdneri ◽  
Electrolyte Balance ◽  
Toxicant Concentration

Acidification of streams and rivers associated with rainstorm or snowmelt events is often episodic as are many environmental introductions of toxic substances. We examined the toxicity of continuous or intermittent exposures to sulfuric acid (H+) to brook trout (Salvelinus fontinalis) embryos, alevins, and fry. Acute toxicity tests were conducted with juvenile rainbow trout (Salmo gairdneri). These studies permitted evaluation of key components of intermittent exposures (toxicant concentration, exposure duration, and recovery period) on mortality, reduced growth, and perturbed electrolyte balance. Lethality of H+ markedly changed with developmental stage of brook trout. Resistance of the chorion to H+ penetration probably protected embryonic fish, while hatching and onset of active swimming exacerbated H+ toxicity. Response surface methods demonstrated that between pH 4 and 7, time–concentration relationships for H+ toxicity were greatly influenced by exposure duration and peak concentration but little by length of recovery period. Daily pulses at pH 4 with duration as short 4.5 h produced marked mortality after 90 d. This did not occur after 4–60 d of testing. Whole-body Na+, K+, and Ca2+ concentrations of brook trout were negatively correlated with mean H+ concentrations after 90 d of exposure. Cation depletion appeared to be a more sensitive index of chronic, sublethal H+ toxicity than reduced growth.

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.

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

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

Influence of pH on the Acute Lethality of Fenitrothion, 2,4-D, and Aminocarb and Some pH-Altered Sublethal Effects of Aminocarb on Rainbow Trout (Salmo gairdneri)

1988 ◽  
Vol 45 (2) ◽  
pp. 287-293 ◽  
Author(s):  
K. G. Doe ◽  
W. R. Ernst ◽  
W. R. Parker ◽  
G. R. J. Julien ◽  
P. A. Hennigar
Keyword(s):  
Rainbow Trout ◽  
Sublethal Effects ◽  
Acetylcholinesterase Activity ◽  
Whole Body ◽  
Toxicity Tests ◽  
Salmo Gairdneri ◽  
Control Range ◽  
Decreasing Ph ◽  
Influence Of Ph ◽  
Brain Acetylcholinesterase

Three pesticides, fenitrothion, 2,4-D, and aminocarb, were tested in static 96-h acute lethal toxicity tests using fingerling rainbow trout (Salmo gairdneri) at pH 4.6, 5.6, 6.9, and 8.5. The toxicity of aminocarb, a base, increased significantly with increasing pH. Conversely, the toxicity of the acidic pesticide 2,4-D increased with decreasing pH. The toxicity of the neutral pesticide fenitrothion did not change significantly with changing pH. Subsequent tests were performed on trout fingerlings with aminocarb to determine the effect of two exposure pH's on brain acetylcholinesterase activity and whole-body aminocarb residue. Brain acetylcholinesterase was found to be inversely proportional to whole-body aminocarb content of fish. In fish exposed at pH 4.6, brain acetylcholinesterase was maximally depressed at 6 h, after which it recovered to within the control range. Whole-body aminocarb concentrations rose to a maximum within 6 h and subsequently declined to low levels. In fish exposed at pH 8.2, brain acetylcholinesterase dropped below the control range by 1 h and remained low until all fish died by 72 h. A maximum whole-body aminocarb concentration was reached within 1 h and remained elevated until the fish died. Several explanations for the observed results are presented.

Isolation of Infectious Pancreatic Necrosis Virus from the Blood and Blood Components of Experimentally Infected Trout

1982 ◽  
Vol 39 (1) ◽  
pp. 225-228 ◽  
Author(s):  
Robert N. Swanson ◽  
James H. Gillespie
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Pancreatic Necrosis ◽  
Salvelinus Fontinalis ◽  
Infectious Pancreatic Necrosis Virus ◽  
Salmo Gairdneri ◽  
Blood Components ◽  
Necrosis Virus ◽  
Infectious Pancreatic Necrosis ◽  
Pancreatic Necrosis Virus

Experimental infection with infectious pancreatic necrosis virus (IPNV) was achieved in yearling rainbow trout (Salmo gairdneri) and 7-mo-old brook trout (Salvelinus fontinalis) by intraperitoneal inoculation and by water contact, respectively. Blood removed periodically from both groups of fish was fractionated and various blood components examined for virus. IPNV was recovered consistently from the plasma and mononuclear-enriched blood fractions of the rainbow trout from 1 to 19 d postinoculation (DPI) and also was detected in the mononuclear fraction on 33 DPI. In the brook trout virus was recovered from 3 to 40 DPI in the plasma and from 7 to 40 DPI in the mononuclear fraction. Thus a viremia appeared to be important in the early stages of experimental IPNV infection and infectious virus was found both free in the plasma and in association with an undetermined cell population present in the mononuclear component of blood.Key words: infectious pancreatic necrosis, blood, fish disease, Salmo gairdneri, Salvelinus fontinalis

Risk to Salmonids of Water Quality in the Turkey Lakes Watershed as Determined by Bioassay

1988 ◽  
Vol 45 (S1) ◽  
pp. s127-s135 ◽  
Author(s):  
W. Kwain ◽  
J. R. M. Kelso
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Lake Trout ◽  
Exposure Period ◽  
Whole Body ◽  
Salmo Gairdneri ◽  
Number Of Factors ◽  
Metal Levels ◽  
Turkey Lakes Watershed

Batchawana Lake, the headwater lake in the Turkey Lakes Watershed, was devoid offish. Although a number of factors could cause this fishless state, we conducted in situ studies to partially address conditions related to lake acidification. The spring pH depression did not induce significant, consistent mortality to rainbow trout (Salmo gairdneri) or lake trout (Salvelinus namaycush) caged in situ. In 1981, however, considerable mortality occurred to fish caged in Batchawana Lake during or immediately following the maximum spring pH depression. In the remaining lakes, mortality occurred later in the exposure period. Whole-body concentrations of Na+, Ca2+, and Mg2+ in rainbow trout caged (1980) in three lakes of the watershed were similar; however, K+ appeared slightly higher (but not statistically different) in fish held in the headwater lake. Static bioassays indicated that the 96-h pH-LC50 for brook trout (Salvelinus fontinalis) was 3.80–4.09, considerably lower than the lowest pH, 4.66, observed during spring. Brook trout corralled in Batchawana Lake grew slightly faster and accumulated more Pb and Hg than fish held in a downstream lake. Although pH and trace metal levels in Batchawana Lake may at times be inhospitable to fish, other factors likely contributed to the fishless condition of this lake.

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