Report of the metacestode of Paradilepis simoni Rausch, 1949 (Cyclophyllidea: Dilepidae) from fish in British Columbia

1982 ◽  
Vol 60 (2) ◽  
pp. 184-186 ◽  
Author(s):  
Hilda Lei Ching
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Oncorhynchus Nerka ◽  
Salmo Gairdneri ◽  
Size And Shape ◽  
Larval Stages ◽  
Prosopium Williamsoni

Larval stages of tapeworms were found encysted in the livers of the following fish: 77% of 87 Oncorhynchus nerka (Walbaum), kokanee; 22% of 111 Salmo gairdneri (Richardson), rainbow trout; 13% of 113 Ptychocheilus oregonensis (Richardson), northern squawfish; 3% of 98 Prosopium williamsoni (Girard), mountain whitefish; and 2% of 85 Cottus asper (Richardson), prickly sculpin. The metacestodes were identified to be that of Paradilepis simoni from the number, size, and shape of the rostellar hooks.

The life histories and trophic relationships of the Trichoptera of Marion Lake, British Columbia

1971 ◽  
Vol 49 (5) ◽  
pp. 623-635 ◽  
Author(s):  
Michael J. Winterbourn
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Life Histories ◽  
Oncorhynchus Nerka ◽  
Trophic Relationships ◽  
Salmo Gairdneri ◽  
Taricha Granulosa ◽  
Kokanee Salmon ◽  
Competitive Species ◽  
Species Being

Life histories and trophic relationships of Trichoptera were studied in a small British Columbia lake. Larvae of 10 caddis species were primarily sediment feeders, 2 were leaf feeders, 3 carnivores, and 1 Banksiola crotchi, an algal feeder in early instars and predaceous in later ones. The final instar larvae of potentially competitive species tended to be separated in time. Caddis larvae were an important component of the diet of rainbow trout (Salmo gairdneri), species being preyed upon sequentially as their later instars appeared in the lake. Larvae were also important as prey of the salamander Taricha granulosa but were less significant in the diets of kokanee salmon (Oncorhynchus nerka) and a second salamander Ambystoma gracile.

The development of Philonema oncorhynchi (Nematoda: Philometridae) in Cyclops bicuspidatus in relation to temperature

1969 ◽  
Vol 47 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Ronald C. Ko ◽  
James R. Adams
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Larval Development ◽  
Sockeye Salmon ◽  
Natural Infection ◽  
Salmo Gairdneri ◽  
Infective Stage ◽  
Final Size ◽  
Rate Of Development ◽  
Larval Stages

Development of Philonema oncorhynchi was followed in Cyclops bicuspidatus kept at 4°, 10°, and 15 °C. The nematode molted twice in the haemocoel of copepods. Three larval stages are described. The final size of the infective stage was unaffected by temperature. The rate of larval development was directly proportional to temperature between 4° and 15 °C. An increase of 5 °C halved the rate. The significance of these findings to the natural infection of sockeye salmon in Cultus Lake, British Columbia, is discussed.The development of P. agubernaculum from the rainbow trout, Salmo gairdneri, was studied at 10 °C by the same methods. Morphological features and rate of development were similar to those of P. oncorhynchi.

Occurrence of the eyefluke, Diplostomum (Diplostomum) baeri bucculentum Dubois et Rausch, 1948, in salmonid fishes of northern British Columbia

1985 ◽  
Vol 63 (2) ◽  
pp. 396-399 ◽  
Author(s):  
Hilda Lei Ching
Keyword(s):  
Rainbow Trout ◽  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Lake Trout ◽  
Infected Fish ◽  
Salmo Gairdneri ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Dolly Varden Salvelinus Malma ◽  
Prosopium Williamsoni

As a result of experimental infections in chicks, diplostomula found in the retina of chinook salmon from the Nechako River were identified as Diplostomum (Diplostomum) baeri bucculentum. Eyeflukes in other salmonids were considered to be the same species based on similar measurements and site in the eyes. These eyeflukes varied in prevalence and mean intensity in seven salmonid species surveyed in nine localities in 1979–1981. The following fish were sampled: rainbow trout (Salmo gairdneri), 505; mountain whitefish (Prosopium williamsoni), 334; lake whitefish (Coregonus clupeaformis), 32; Dolly Varden (Salvelinus malma), 66; lake trout (S. namaycush), 13; kokanee or sockeye salmon (Oncorhynchus nerka), 323; and chinook salmon (O. tshawytscha), 164. Eyeflukes had prevalences ranging from 84 to 100% in six lakes, 64% in the river, 53% in one reservoir site, and a prevalence of 15% in the other reservoir site. Mountain and lake whitefishes had high mean intensities while kokanee had low mean intensities. Correlation of increased intensity with increased fish size was significant for 6 of 27 samples. Four samples of lake whitefish, mountain whitefish, rainbow trout, and chinook salmon showed significant asymmetry when numbers of diplostomula were compared between eyes. More of the heavily infected fish showed asymmetry than did the lightly infected fish.

Nest digging behavior of rainbow trout (Salmo gairdneri)

1970 ◽  
Vol 48 (6) ◽  
pp. 1458-1462 ◽  
Author(s):  
G. F. Hartman
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Wild Population ◽  
Salmo Gairdneri ◽  
Tactile Stimuli ◽  
Digging Behavior ◽  
Nest Digging

A wild population of rainbow trout (Salmo gairdneri) was observed during spawning in the Lardeau River in southeastern British Columbia, in April and May in 1966 and 1967. Nest digging in the first few days of spawning in 1967 was predominantly nocturnal, but diurnal nest digging increased until activity was nearly steady around the clock.Rate of digging (digging bouts per 10-min interval) averaged near five before spawning, rose sharply immediately after spawning, and then decreased. The number of body flexures per bout of digging was near six before spawning, decreased sharply right after spawning, and then rose progressively over a 50-min period. Touching or feeling the bottom of the nest was frequent before spawning and decreased after. The effect of internal stimuli (egg release) and tactile stimuli on digging behavior is considered.

Molybdenum Concentrations in Tissues of Rainbow Trout (Salmo gairdneri) and Kokanee Salmon (Oncorhynchus nerka) from Waters Differing Widely in Molybdenum Content

1973 ◽  
Vol 30 (6) ◽  
pp. 841-842 ◽  
Author(s):  
James V. Ward
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Nerka ◽  
Weight Basis ◽  
Molybdenum Content ◽  
Salmo Gairdneri ◽  
Kokanee Salmon ◽  
Water Fish ◽  
Wet Weight ◽  
Molybdenum Concentration

Concentrations of molybdenum in tissues of rainbow trout (Salmo gairdneri) from three waters increased only slightly with increase in molybdenum concentration of the water. Fish from high (300 ppb) molybdenum water had mean concentrations of 13–332 ppb on a wet-weight basis; those from low (6 ppb) molybdenum water, 10–146 ppb; and those from trace molybdenum water, 5–118 ppb. Rainbow trout exhibited generally higher molybdenum concentrations than did kokanee salmon (Oncorhynchus nerka) in high molybdenum water. A possible plateau mechanism concerning molybdenum accumulation by salmonids is discussed.

Factors Affecting Rainbow Trout (Salmo gairdneri) Predation on Migrant Fry of Sockeye Salmon (Oncorhynchus nerka)

1976 ◽  
Vol 33 (1) ◽  
pp. 19-24 ◽  
Author(s):  
R. M. Ginetz ◽  
P. A. Larkin
Keyword(s):  
Rainbow Trout ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Development Stage ◽  
Salmo Gairdneri ◽  
Factors Affecting ◽  
Light Intensities ◽  
Salmon Fry ◽  
Lower Stream ◽  
Downstream Movement

Predation of rainbow trout (Salmo gairdneri) on migrant sockeye salmon (Oncorhynchus nerka) fry in experimental streams was higher on fry at an earlier development stage, in moonlight by contrast to cloudy night light intensities, at lesser turbidities, and at lower stream velocities. At dusk light intensities, from.05 to.30 ft-c, mortality from predation was inversely related to light intensity. The longer the period of exposure of fry to naturally declining light intensities prior to downstream movement, the lower was the loss to predators. Exposure of predators to high light intensities prior to the downstream movement of fry resulted in decreased fry mortality. Fry that had survived exposure to predators in an experimental stream 1 and 2 days previous were less vulnerable to predation than "naive" fry. Successive exposures further decreased the loss to predation. Fry enumerated at a counting fence suffered less predation than fry not enumerated. Experienced fry moved downstream more rapidly than naive fry.In laboratory aquaria, experienced fry formed compact schools prior to and in response to stimuli, while naive fry formed loose schools or did not school. Experienced fry were less active in responding to stimuli. Enumerated fry resembled experienced fry; nonenumerated fry resembled naive fry.Various techniques of enhancing sockeye salmon fry survival during downstream migration are suggested by these results.

First Record of Bacterial Kidney Disease in an Apparently Wild Salmonid in British Columbia

1973 ◽  
Vol 30 (10) ◽  
pp. 1578-1580 ◽  
Author(s):  
T. P. T. Evelyn ◽  
G. E. Hoskins ◽  
G. R. Bell
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Kidney Disease ◽  
First Record ◽  
Wild Fish ◽  
Salmo Gairdneri ◽  
Bacterial Kidney Disease ◽  
Causative Bacterium

A confirmed case of bacterial kidney disease in a sports-caught rainbow trout (Salmo gairdneri) from Loon Lake, British Columbia, is reported. The case represents the first record of this disease in an apparently wild fish in this province. Descriptions of the affected trout and of the causative bacterium are provided.

Kudoa thyrsites (Gilchrist, 1924) (Myxozoa) in the cardiac muscle of Pacific salmon (Oncorhynchus spp.) and steelhead trout (Salmo gairdneri)

1989 ◽  
Vol 67 (2) ◽  
pp. 341-342 ◽  
Author(s):  
Z. Kabata ◽  
D. J. Whitaker
Keyword(s):  
British Columbia ◽  
Cardiac Muscle ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Salmo Gairdneri ◽  
Oncorhynchus Keta ◽  
Steelhead Trout ◽  
Myxozoan Parasite ◽  
Kudoa Thyrsites ◽  
Pacific Salmonids

An examination of the cardiac muscle of returning adults of all species of British Columbia Pacific salmonids, including steelhead trout (Salmo gairdneri), for infection by the myxozoan parasite Kudoa thyrsites showed that all species but chum (Oncorhynchus keta) and sockeye (Oncorhynchus nerka) are susceptible to infection. The prevalence of observed infection was low. Its intensity was not determined, but the small numbers of spores observed suggest that it was low. The possible causes of these observations are discussed.

Effect of Metopirone on Pituitary–Interrenal Function in Two Teleosts, Sockeye Salmon (Oncorhynchus nerka) and Rainbow Trout (Salmo gairdneri)

1968 ◽  
Vol 25 (7) ◽  
pp. 1465-1474 ◽  
Author(s):  
Ulf H. M. Fagerlund ◽  
J. R. McBride ◽  
Edward M. Donaldson
Keyword(s):  
Rainbow Trout ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Inhibitory Effect ◽  
Salmo Gairdneri ◽  
Pars Distalis ◽  
Marked Inhibitory Effect ◽  
Interrenal Cells ◽  
Rostral Region ◽  
Low Dosage

Metopirone (SU 4885), an inhibitor of 11β-hydroxylation of adrenocorticosteroids, was administered intramuscularly to adult castrated sockeye salmon (Oncorhynchus nerka) and intact rainbow trout (Salmo gairdneri). Marked hypertrophy of interrenal cells pointed to an increase in the activity of the interrenal tissue of both species. Increased cortisol concentrations in trout at low dosage levels of metopirone suggested that the drug was stressful. However, decreased concentrations at higher dosage levels in trout, and decreased cortisol concentrations in all salmon indicated that the drug was also exerting a marked inhibitory effect on 11β-hydroxylation. In salmon, a repository ACTH preparation (acthar) brought about interrenal hypertrophy similar to that produced by metopirone. Metopirone also induced degranulation and hyperplasia of the cells of the palisade-like layer in the rostral region of the pars distalis in both species of fish. These cells were the only cell type of the pars distalis that were stained with lead-haematoxylin. The evidence indicates that they are the corticotrops.

Lakeward Migration of Young Rainbow Trout (Salmo gairdneri) in the Upper Lardeau River, British Columbia

1969 ◽  
Vol 26 (1) ◽  
pp. 33-45 ◽  
Author(s):  
T. G. Northcote
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Water Temperature ◽  
Water Current ◽  
Salmo Gairdneri ◽  
Field Observations ◽  
Predominant Role ◽  
Emergence Period ◽  
Trout Lake ◽  
Kootenay Lake

Lakeward migration of rainbow trout fry was studied in the upper Lardeau River, where the young emerge from a spawning area immediately below the outlet of Trout Lake utilized by large trout from Kootenay Lake, about 56 km downstream. Most fry move downstream towards Kootenay Lake shortly after emergence; however, some, particularly later in the emergence period, move upstream into Trout Lake. Field observations and experiments suggest that water temperature may be important in inducing different responses to water current in these fish, but may not play such a predominant role or operate at the same levels as proposed earlier for control of young trout migration in the Loon Lake system.

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