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At least 1,225 records · Page 68Linked to original sources
USGS1974

Comparison of protection in rainbow trout (Salmo gairdneri) inoculated with and fed Hagerman redmouth bacterins

Rainbow trout ( Salmo gairdneri ) fed 1.0 mg Hagerman redmouth bacterin per fish for 2 wk had no detectable specific, circulating, agglutinating antibody. In fish given a single subcutaneous inoculation of 1.0 mg of bacterin per fish, antibody was present from 3 wk later until 3 mo later, when the final sample was taken. Median lethal doses at various intervals after the bacterins were administered indicated that the inoculated fish could withstand a greater challenge by subcutaneous inoculation of the virulent bacteria than the orally immunized fish. The fish fed the vaccine lost their protection within 6 wk, whereas the inoculated fish had high levels of protection through 3 mo. The degree of protection was also confirmed by a "natural" exposure challenge.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Pathophysiology of infectious hematopoietic necrosis virus disease in rainbow trout (Salmo gairdneri): early changes in blood and aspects of the immune Response after Injection of IHN Virus

Juvenile rainbow trout ( Salmo gairdneri ) were injected with infectious hematopoietic necrosis (IHN) virus and various hematological and blood chemical changes were monitored over 9 days. The packed cell volume, hemoglobin, red blood cell count, and plasma bicarbonate were significantly depressed by day 4. Plasma chloride, calcium, phosphorus, total protein, and blood cell types did not change during the 9 days. Furthermore, plasma LDH isozyme was significantly increased by the fourth day, and fish infected with infectious pancreatic necrosis virus, Vibrio anguillarum , Aeromonas salmonicida , and redmouth bacterium did not show specific LDH isozyme alterations. Acid-base alterations occurred at 10 C but not at 18 C. The acid-base imbalance and elevation of the LDH isozyme were consistently associated with the early development of the disease.The immune response after injection of IHN virus was determined and protection from disease was tested by passive immunization. Actively immunized fish developed IHN-neutralizing antibodies within 54 days after injection of virus, and the antibodies were protective when juvenile fish were passively immunized and experimentally challenged with IHN virus.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Effect of temperature on accumulation of methylmercuric chloride and p,p'DDT by rainbow trout (Salmo gairdneri)

Amounts of mercury and DDT residues accumulated from water by yearling rainbow trout ( Salmo gairdneri ) in the laboratory increased as water temperature increased. Fish exposed to methylmercuric chloride at concentrations of 234&ndash;263 parts per trillion for 12&ensp;wk at 5, 10, and 15&ensp;C accumulated 1.19, 1.71, and 1.96&ensp;ppm; fish exposed to p , p &prime;DDT at concentrations of 133&ndash;176 parts per trillion accumulated 3.76, 5.93, and 6.82&ensp;ppm. Concentrations of mercury accumulated by the fish were significantly different ( P &ensp;<&ensp;0.01) at each of the three temperatures, and the concentrations of DDT were significantly different at 5 and 10 and 5 and 15&ensp;C. Throughout the period of exposure, the concentration factors (concentration of contaminant in the fish/concentration in water) at each of the three temperatures were far higher for p , p &prime;DDT than for methylmercuric chloride.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Effect of feeding brown trout (Salmo trutta) a diet pelleted in dry and moist forms

Growth rate, body composition, and intake of either dry matter or energy did not differ significantly ( P > 0.05) between two groups of juvenile brown trout ( Salmo trutta ) fed either a low- or high-moisture semipurified diet at different rates to compensate for a diet energy density gradient. Feed/gain efficiency, on an as-fed basis, was significantly greater ( P < 0.01) in fish fed the low-moisture diet, but did not differ ( P > 0.05) when compared on the basis of dry matter or energy intake.

Journal of the Fisheries Research Board of Canada↗
USGS1975

Statistical methods for estimating normal blood chemistry ranges and variance in rainbow trout (Salmo gairdneri), Shasta Strain

Gaussian and nonparametric (percentile estimate and tolerance interval) statistical methods were used to estimate normal ranges for blood chemistry (bicarbonate, bilirubin, calcium, hematocrit, hemoglobin, magnesium, mean cell hemoglobin concentration, osmolality, inorganic phosphorus, and pH for juvenile rainbow ( Salmo gairdneri , Shasta strain) trout held under defined environmental conditions. The percentile estimate and Gaussian methods gave similar normal ranges, whereas the tolerance interval method gave consistently wider ranges for all blood variables except hemoglobin. If the underlying frequency distribution is unknown, the percentile estimate procedure would be the method of choice.

Journal of the Fisheries Research Board of Canada↗
USGS1976

Inbreeding in rainbow trout (Salmo gairdneri)

Effects of inbreeding on rainbow trout ( Salmo gairdneri ) were evaluated by a comparison of differences between inbred and outbred half-sib families reared as contemporaries during the 1st yr of life. Attention was focused on two levels of inbreeding expressed as inbreeding coefficients: F = 0.25, one generation of brother–sister matings, and F = 0.375, two generations of brother–sister matings. Although inbreeding at the F = 0.25 level in fall-spawning populations had no effect on egg hatchability, it significantly increased the frequency of crippled fry by 37.6% and significantly decreased feed conversion efficiency (5.6%), fry survival to 147 days (14.6%), and growth rate to 147 days (6%) and 364 days (23.2%). Effects of inbreeding at F = 0.375 were more pronounced; significant differences included increased frequency of crippled fry (191.5%) and decreased feed conversion efficiency (14.9%), fry survival to 147 days (29.7%), and growth rate to 147 day s (13.4%) and 364 days (33.5%). Application of the total effects of inbreeding on the number of fish remaining and the weight of fish remaining in a production lot at 1 yr of age indicated losses of 17.4 and 36.6% after one generation (F = 0.25) and 47.9 and 65.4% after two generations (F = 0.375) of brother–sister mating. Similar studies on a spring-spawning population produced similar results. General breeding methods that minimize the rate of inbreeding accumulation are discussed.

Journal of the Fisheries Research Board of Canada↗
USGS1976

Physiological response of juvenile coho salmon (Oncorhynchus kisutch) and rainbow trout (Salmo gairdneri) to handling and crowding stress in intensive fish culture

Moving 4&ndash;5-in. coho salmon ( Oncorhynchus kisutch ) held in soft (20&ensp;ppm CaCO 3 ) water from the relatively light loading density of 0.5&ensp;lb/ft 3 to 1, 2, or 4&ensp;lb/ft 3 (density index, DI&ensp;=&ensp;0.1, 0.2, 0.4, 0.8) caused significant stress as indicated by loss of feeding behavior, but only minimal physiological disturbances, as indicated by lack of hyperglycemia or hypochloremia. However, moving them to 6 or 12&ensp;lb/ft 3 (DI&ensp;=&ensp;1.2, 2.4) caused significant physiological stress which required at least a week for recovery. Smolting coho salmon were physiologically stressed by population densities of 1&ensp;lb/ft 3 or more and a subclinical corynebacterial kidney infection was activated. Rainbow trout ( Salmo gairdneri ) (4&ndash;5&ensp;in.) were physiologically stressed when moved and held at 1&ensp;lb/ft 3 or more but retained normal feeding behavior. This indicates that handling and crowding stress will be minimized in softwater areas if densities in fish distribution trucks or in ponds or raceways during disease treatments are held to 0.1&ndash;0.5&ensp;lb/gal.

Journal of the Fisheries Research Board of Canada↗
USGS1977

Genetic differences in growth and survival of juvenile hatchery and wild steelhead trout, Salmo gairdneri

Relative growth and survival of offspring from matings of hatchery and wild Deschutes River (Oregon) summer steelhead trout, Salmo gairdneri , were measured to determine if hatchery fish differ genetically from wild fish in traits that can affect the stock–recruitment relationship of wild populations. Sections of four natural streams and a hatchery pond were each stocked with genetically marked (lactate dehydrogenase genotypes) eyed eggs or unfed swim-up fry from each of three matings: hatchery × hatchery (HH), hatchery × wild (HW), and wild × wild (WW). In streams, WW fish had the highest survival and HW fish the highest growth rates when significant differences were found; in the hatchery pond, HH fish had the highest survival and growth rates. The hatchery fish were genetically different from wild fish and when they interbreed with wild fish may reduce the number of smolts produced. Hatchery procedures can be modified to reduce the genetic differences between hatchery and wild fish.

Oregon↗
USGS1977

Differences in swimming performance among strains of rainbow trout (Salmo gairdneri)

Swimming performance profiles, relating fish size to swimming time, were established for three strains of rainbow trout ( Salmo gairdneri ). No differences were found in slope of regressions; only in level at each size of fish. Swimming performances of New Zealand and Sand Creek strains did not differ, but were superior to the Manchester strain. In stamina results from 189-day-old fish from individual matings of seven strains and various crosses, similar strains and crosses had closely matching profiles whereas profiles of unrelated groups were variable. Comparison of slowest, average, and fastest growing fish within the New Zealand strain showed that swimming ability was not related to growth rate.

Journal of the Fisheries Research Board of Canada↗
USGS1977

Tests for association of transferrin and lactate dehydrogenase phenotypes with weight gain in rainbow trout (Salmo gairdneri)

Transferrin (Tf) phenotype was associated with weight gain in 147- and 230-day-old rainbow trout, but no association was found between lactate dehydrogenase (LDH) phenotype and weight gain. A total of 2038 progeny were examined from two different environments. Progeny lots were reared at densities below those known to affect mean fish weights. Differential survival among progeny with respect to their Tf of LDH phenotype was not detected.

Journal of the Fisheries Research Board of Canada↗
USGS1978

Prevention and treatment of Nitrite toxicity in juvenile steelhead trout ( Salmo gairdneri )

The efficacy of mineral salts, pH, and tetramethylthianine (methylene blue) treatment in reducing the acute toxicity of nitrite to fingerling steelhead trout ( Salmo gairdneri ) was determined using a static bioassay system at 10 &deg;C. The acute toxicity (96-h LC50) was reduced by a factor of about 24 for 5-g steelhead and 13 for 10-g fish when the total water hardness was increased from 25 to 300&ensp;mg/L (as CaCO 3 ). NaCl or CaCl 2 additions (0&ndash;200&ensp;mg/L) reduced toxicity by a factor of up to 3 for NaCl and 50 for CaCl 2 . Increasing the pH from 6.0 to 8.0 decreased toxicity by a factor of about 8 for the smaller and 3 for the larger fish. Methylene blue at 0.1 or 1.0&ensp;mg/L was effective in decreasing acute toxicity. For alleviating methemoglobinemia, removing the fish to freshwater for 48&ensp;h was about as effective as 1.0&ensp;mg/L methylene blue. Chronic exposure in soft water to 0.03&ensp;mg/L NO 2 -N for 6&ensp;mo caused no significant growth reduction, gill histological changes, hematological dyscrasias, or impaired ability of the smolts to adapt to 30&permil; seawater and grow for an additional 2&ensp;mo. Key words : nitrite, toxicity, fish, methylene blue, pH, salts, acute toxicity, chronic toxicity

Journal of the Fisheries Research Board of Canada↗
USGS1979

Physiological and biochemical aspects of ozone toxicity to rainbow trout ( Salmo gairdneri )

An acute toxicity curve for dissolved ozone (O 3 ) in soft water at 10 &deg;C, using 10&ndash;13-cm rainbow trout ( Salmo gairdneri ) as the test species was calculated. The 96-h LC50 (95%, confidence interval) was 9.3 (8.1&ndash;10.6)&ensp;&mu;g/L. The lethal threshold level was about 8&ensp;&mu;g/L mandating that a conservative margin of safety be used if ozone is employed as a fish disease control agent. Death apparently results from massive destruction of the gill lamellar epithelium together with a severe hydromineral imbalance. In partial chronic (3-mo) testing, 2&ensp;&mu;g/L caused no significant biological damage while 5&ensp;&mu;g/L caused some gill pathological changes and reduced feeding behavior. Accordingly, 2&ensp;&mu;g/L is suggested as a provisional maximum safe exposure level, pending completion of life cycle studies. Thus, if ozone-treated water is discharged into the environment, dissolved O 3 should be reduced to at least the 2&ensp;&mu;g/L level to minimize adverse impacts on salmonids in receiving waters.

Journal of the Fisheries Research Board of Canada↗
USGS1979

Plaque-forming cells and humoral antibody in rainbow trout (Salmo gairdneri) induced by immersion in a Yersinia ruckeri O-antigen preparation

Rainbow trout ( Salmo gairdneri ) were exposed to the O-antigen of Yersinia ruckeri by various immunization regimens. The passive hemolytic plaque assay was used to show specific splenic plaque-forming cells (PFC) and passive hemagglutination demonstrated humoral antibody titers in fish injected with or immersed in the antigen preparations. Preceding antigen immersion with a 2-min immersion in either a 5.2 or a 2.6% NaCl solution did not affect the numbers of PFC or levels of antibody. Fish held for 2 min in ethyl m -aminobenzoate methanesulfonate (MS-222 ® ) before antigen immersion showed no significant difference from the control fish. Dosage studies showed that the minimal concentration of antigen for induction of PFC by immersion was 5.0 μg/mL.

Journal of the Fisheries Research Board of Canada↗
USGS1980

Classification of sea lamprey ( Petromyzon marinus ) attack marks on Great Lakes lake trout ( Salvelinus namaycush )

Criteria for the classification of marks inflicted by sea lamprey ( Petromyzon marinus ) into nine categories were developed from laboratory studies in an attempt to refine the classification system used in field assessment work. These criteria were based on characteristics of the attachment site that could be identified under field conditions by unaided visual means and by touching the attachment site. Healing of these marks was somewhat variable and was influenced by the size of lamprey, duration of attachment, severity of the wound at lamprey detachment, season and water temperature, and by other less obvious factors. Even under laboratory conditions staging of some wounds was difficult, especially at low water temperatures. If these criteria are to be used effectively and with precision in the field, close examination of individual fish may be required. If the feeding and density of specific year-classes of sea lampreys are to be accurately assessed on an annual basis, close attention to the wound size (as it reflects the size of the lamprey's oral disc) and character of wounds on fish will be required as well as consideration of the season of the year in which they are observed. Key words : sea lamprey, attack marks, lake trout, Great Lakes

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1991

Nature and time course of acclimation to aluminum in juvenile brook trout ( Salvelinus fontinalis ): II. Gill histology

Gill samples from juvenile brook trout ( Salvelinus fontinalis ) acclimated to low-level aluminum at pH 5.2 showed severe damage by day 4, with necrosis and fusion of secondary lamellae and hyperplasia and hypertrophy of mucous cells. Over the following 20&ensp;d, there was a continual process of repair with proliferation and hypertrophy of mucous cells. Qualitative analysis of gill samples plus physiology and mortality data collected in a companion study indicated progressive development (by day 10 onward) of increasing acclimation to Al. Quantitative analysis of gill samples on day 13 showed that mucous cell volume density had tripled and mucous cell area had doubled in Al-exposed fish compared with control fish. A lamellar fusion index showed evidence of fusion in Al-exposed fish by day 4 with recovery to nearly control levels by day 13. Physiological disturbances appear to be directly related to the histological changes observed in the gill epithelium. At the cellular level, changes in either mucous cell production and secretion or changes in mucus chemistry contribute, in part, to acclimation to Al.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1966

Description of a bacterium associated with redmouth disease of rainbow trout ( Salmo gairdneri )

A description was given of a gram-negative, peritrichously flagellated, fermentative bacterium that was isolated on numerous occasions from kidney tissues of rainbow trout ( Salmo gairdneri ) afflicted with redmouth disease. Although the bacteria apparently were members of the family Enterobacteriaceae, it was impossible to determine their taxonomic position within the family with certainty. Hence it was recommended that their taxonomic position remain sub judice for the present. As a temporary designation RM bacterium was used. Redmouth disease was transmitted from infected to normal fish through the medium of water.

Canadian Journal of Microbiology↗