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At least 325 records · Page 18Linked to original sources
USGS1976

Relative effect of two dietary water-soluble analogues of menaquinone on coagulation and packed cell volume of blood of lake trout (Salvelinus namaycush)

Triplicate lots of fingerling lake trout ( Salvelinus namaycush ) (initial mean weight, 5.3 g) were fed a basal, semipurified diet, or this basal diet supplemented with either 1.0 or 2.0 ppm of either menadione sodium bisulfite (MSB) or menadione dimethylpyrimidinol bisulfite (MPB) for 18 wk at 14 C. Neither form of vitamin K had a significant effect on the growth, food conversion, or body composition of the fish.Fish fed 1 ppm of MSB had a significantly higher mean packed cell volume (PCV) than those fed 2 ppm of either analogue. Trout fed 2 ppm of MPB had an intermediate PCV which was not significantly different from that of trout fed either 1 ppm MPB or 2 ppm MSB. A dietary level of 1 ppm MPB (providing an equivalent menaquinone concentration of about 0.5 mg/kg of diet) is sufficient to insure normal coagulation of lake trout blood and a satisfactory PCV.

Journal of the Fisheries Research Board of Canada↗
USGS1976

Optimum level of dietary biotin for growth, feed utilization, and swimming stamina of fingerling lake trout (Salvelinus namaycush)

Triplicate lots of fingerling lake trout ( Salvelinus namaycush ) held at 9 C for 20 wk were fed a semipurified basal diet supplemented with 1% spray-dried egg white or d-biotin at concentrations of 0.1, 0.5, 1.0, or 5.0 ppm. Trout fed the basal diet, either alone or with egg white, grew more slowly and converted feed less efficiently ( P < 0.05) than those fed supplemental biotin. Neither the growth rate nor feed conversion differed significantly among the four groups fed supplemental biotin. However, when forced to swim to exhaustion against controlled water currents, trout fed either basal diet, with or without egg white, or 0.1 ppm supplemental biotin, swam a shorter distance ( P < 0.05) than those fed more biotin. Fish fed 0.5 ppm biotin swam as far as those fed 1.0 ppm, but not as far as those fed 5.0 ppm. These results indicate that young lake trout probably need no more than 0.1 ppm biotin for optimum growth and feed conversion, but require from 0.5 to 1.0 ppm for optimum swimming stamina.

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

Glomerular mesangial fibrosis in hatchery-reared rainbow trout (Salmo gairdneri)

Light and electron microscopic studies were performed on tissues of hatchery-reared rainbow trout ( Salmo gairdneri ) having a disease of currently unknown etiology with external symptoms of severe edema which causes increased mortality rate. Comparison with unaffected trout tissues revealed loss of cellularity in glomerular tufts with a replacement of mesangial cells by connective tissue. Ultrastructural studies showed the material to be collagen and established the diagnosis of glomerular mesangial fibrosis. The glomerular lesion was associated with alterations in lining epithelium of proximal tubules and extensive debris within tubule lumens. The findings are compared to glomerular lesions in mammalian and amphibian kidney.

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

Immunization of pacific salmon: comparison of intraperitoneal injection and hyperosmotic infiltration of Vibrio anguillarum and Aeromonas salmonicida bacterins

Two methods of immunizing fish, intraperitoneal (i.p.) injection and hyperosmotic infiltration, were compared for control of vibriosis and furunculosis in pen-reared coho salmon ( Oncorhynchus kisutch ) and chinook salmon ( O . tshawytscha ). Both methods provided significant protection against vibriosis under field test conditions. In coho salmon, hyperosmotic infiltration provided the best protection and fastest rise in antibody titer of seven treatments tested. In chinook salmon, hyperosmotic infiltration of Vibrio anguillarum and Aeromonas salmonicida vaccines resulted in 83.3% survival in comparison with 28.7% survival in controls. Both i.p. injection and hyperosmotic infiltration of V . anguillarum and A . salmonicida bacterins resulted in production of serum antibodies specific for each respective pathogen. Vaccination with bivalent V . anguillarum &ndash; A . salmonicida vaccines produced antibodies to both pathogens, and provided protection against vibriosis. Growth rates of vaccinated coho salmon were not significantly different from controls.

Journal of the Fisheries Research Board of Canada↗
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

Survival of two bacterial fish pathogens (Aeromonas salmonicida and the Enteric Redmouth Bacterium) in ozonated, chlorinated, and untreated waters

Ozone and chlorine inactivation curves were determined in three water types at 20 &deg;C for the destruction of the fish pathogens Aeromonas salmonicida , the etiologic agent of furunculosis, and the enteric redmouth bacterium (ERM). In phosphate-buffered distilled water, 0.01&ensp;mg/ℓ ozone inactivated 10 3 cells/ml of ERM and A . salmonicida in 1/2 and 10&ensp;min, respectively. Chlorine at this concentration had little effect on either pathogen and a residual of at least 0.05&ensp;mg/ℓ was needed to achieve a complete kill within a 10-min contact time. In soft lake water (30&ensp;mg/ℓ as CaCO 3 ) a chlorine residual of 0.1&ensp;mg/ℓ rapidly inactivated A . salmonicida and ERM but in hard water (120&ensp;mg/ℓ) A . salmonicida was more resistant and 0.2&ensp;mg/ℓ chlorine was required. Ozonation of the two lake waters at 90&ensp;mg O 3 ∙h &minus;1 ∙ℓ &minus;1 (equivalent to a 0.01&ensp;mg/ℓ residual in ozone demand-free water) was required to destroy both pathogens within 10&ensp;min.In untreated soft lake water 10 3 cells/ml of A . salmonicida survived only 2 days, while the ERM bacterium (10 3 cells/ml) survived even after 20 day s in soft and hard untreated lake waters.

Journal of the Fisheries Research Board of Canada↗
USGS1977

Establishment of white perch, Morone americana , in Lake Erie

White perch, Morone americana, was first reported in Lake Erie in 1953. No further reports of capture were recorded until 1973, when one fish was taken. Three other captures were confirmed in 1974, and 34 in 1975. All but 3 of the 38 specimens were taken in the warm, shallow western basin and the extreme eastern end of the central basin. The widespread distribution and the sizable numbers of specimens collected in 1975 strongly indicate that this nonendemic species has become established in Lake Erie.

Journal of the Fisheries Research Board of Canada↗
USGS1977

Changes in yellow perch (Perca flavescens) populations of Lake Michigan, 1954-75

In the early and mid-1960s the abundance of yellow perch ( Perca flavescens ) in Lake Michigan declined abruptly. The decline began in the northern part of the lake and spread progressively southward. Circumstantial evidence suggests that the nonnative alewife ( Alosa pseudoharengus ), by interfering with perch reproduction, was the primary cause of the decline. The alewife was first reported in northeastern Lake Michigan in 1949, and had become extremely abundant throughout the lake before an enormous die-off in 1967 reduced its numbers by an estimated 70%. An intensive fishery hastened the decline of perch. In most areas the decline was immediately preceded by a period of conspicuously high commercial production. This high production appears to have been related in part to increased growth rates of perch resulting from much lower density of younger fish. A sport fishery for perch in shallow water collapsed a few years before the species declined in abundance. The most logical explanation is that heavy concentrations of alewives physically displaced the perch from nearshore areas. Although perch populations increased in some areas in the 1970s, a full recovery is unlikely unless alewife numbers are further reduced.

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↗
USGS1978

Myxosoma cerebralis: Fluorescent antibody techniques for antigen recognition

Rabbits were immunized with antigens extracted from mature spores or prespore stages of Myxosoma cerebralis , and the resulting antisera and their globulins were used in direct and indirect fluorescent antibody techniques. Both kinds of antisera reacted with homologous spores and with stages of the organism that precede spores. When tested for specificity against spores of 12 other myxosporidans the direct fluorescent antibody technique showed cross-reactivity with only one other and that was a species of Myxosoma . The indirect fluorescent antibody technique showed some reactions across generic lines. The antisera have application in studies of the parasite's life cycle and in diagnostics.

Journal of the Fisheries Research Board of Canada↗
USGS1978

Survival of the salmonid viruses infectious hematopoietic necrosis (IHNV) and infectious pancreatic necrosis (IPNV) in ozonated, chlorinated, and Untreated waters

Ozone and chlorine inactivation curves were determined in three water types at 10 &deg;C for the fish pathogenic viruses infectious hematopoietic necrosis (IHNV) and infectious pancreatic necrosis (IPNV). In phosphate-buffered, distilled water (PBDW) an ozone dose of 0.01&ensp;mg/L for 30 or 60&ensp;s inactivated IHNV or IPNV, respectively, suspended at a tissue culture 50% infective dose (TCID50) of 10 4 &ndash;10 5 /mL. In hard (120&ensp;mg/L as CaCO 3 ) and soft water (30&ensp;mg/L) lake waters, an ozone application rate of 70&ensp;mg∙h &minus;1 ∙L &minus;1 for 10&ensp;min destroyed IHNV. IPNV inactivation in hard water required 90&ensp;mg∙O 3 ∙h &minus;1 ∙L &minus;1 for 10&ensp;min but only a 30-s contact time in soft water. The IPNV was also somewhat more resistant to chlorine. In PBDW, a residual of 0.1&ensp;mg/L with contact times of 30 and 60&ensp;s, respectively, destroyed IHNV and IPNV. In soft lake water IHNV was destroyed within 5&ensp;min at 0.5&ensp;mg/L, while in hard water a 10-min contact time was required. For IPNV disinfection in soft water, 0.2&ensp;mg/L for 10&ensp;min was sufficient but this chlorine residual had essentially no effect on IPNV in hard water. Increasing this dose to 0.7&ensp;mg/L destroyed IPNV in hard water within 2&ensp;min. In untreated waters, IPNV was stable for at least 8&ensp;wk in either distilled, soft, or hard lake waters. However, IHNV survived only about 2&ensp;wk in distilled and 7&ensp;wk in the soft or hard lake waters. We suggest the serious consideration of ozone as a fish disease control agent. Key words : ozone, chlorine disinfection, fish pathogens, viruses

Journal of the Fisheries Research Board of Canada↗
USGS1978

Evaluation of an aerial survey of Pacific walruses

An aerial survey of Pacific walruses ( Odobenus rosmarus divergens ) was evaluated to determine the reliability of estimates of population abundance. The probability of detecting groups of walruses on the pack ice remained uniform to at least 0.93 km from the flight line, whereas the probability of detection decreased significantly beyond 0.23 km for walruses in the water. Walruses were more abundant along the ice-edge zone between 162 and 165°W than in other areas of the Chukchi Sea during September 1975. Few walruses were observed in consolidated pack ice north of the ice-edge zone or in ice-free water to the south. More walrus groups and larger mean group size were observed on September 8 than on other days. We estimated abundance for each day and all days combined using methods based on sample area and numbers of strip samples. Estimates varied among days by over an order of magnitude; this variation is attributed to the combined effect of chance sampling of an aggregated population and variation in the fraction of walruses hauled out. The coefficient of variation of the estimates ranged between 0.25 and 0.99. This imprecision was due to the aggregated distribution of walruses and the large variation in group size. Using the survey data as a basis for stratification, we calculated that, due to the high variability within strata, a sample size of 40% of the total area or 56% of the total available strips would be required to obtain 95% confidence limits within 10% of the estimate of total abundance. Variation contributed by observer error in estimating group size also is relatively unimportant to the precision of abundance estimates. Studies of natural history, particularly those oriented toward activity and habitat selection, would help investigators estimate bias due to the variable fraction hauled out and design surveys based on meaningful strata. Estimates of total abundance based on limited survey efforts will provide information of little reliability.

Journal of the Fisheries Research Board of Canada↗