Kudoa thyrsitis (Gilchrist) (Myxosporea: Multivalvulida) in coho salmon, Oncorhynchus kisutch (Walbaum)

1986 ◽  
Vol 64 (4) ◽  
pp. 1038-1040 ◽  
Author(s):  
Z. Kabata ◽  
D. J. Whitaker ◽  
J. W. Bagshaw
Keyword(s):  
British Columbia ◽  
Cardiac Muscle ◽  
Unusual Case ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Unusual Site ◽  
First Report

An unusual case of infection of coho salmon, Oncorhynchus kisutch (Walbaum), in British Columbia, Canada, with a myxosporean Kudoa thyrsitis (Gilchrist) is described. This first report of Kudoa parasitizing a member of the genus Oncorhynchus is interesting also because of the unusual site of Kudoa in the fish, the cardiac muscle.

First report of Loma sp. (Microsporida) in juvenile coho salmon (Oncorhynchus kisutch) from Vancouver Island, British Columbia

1987 ◽  
Vol 65 (3) ◽  
pp. 751-752 ◽  
Author(s):  
Brad G. Magor
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Vancouver Island ◽  
Maximum Intensity ◽  
First Report ◽  
Histopathologic Response

A species of Loma Morrison and Sprague, 1981 (Microsporida) was found in gills of smolt of Oncorhynchus kisutch from a hatchery on Vancouver Island, British Columbia. Prevalence of cysts was 28%. Maximum intensity was 84 cysts per fish. Histopathologic response of gills to cysts was minimal and localized where observed. This is the first report of a species of Loma in wild or captive fishes in western Canadian waters. The significance of its presence here is considered in light of a recent Loma epizootic in Alaska.

scholarly journals Evidence for Freshwater Residualism in Coho Salmon, Oncorhynchus kisutch, From a Watershed on the North Coast of British Columbia

2017 ◽  
Vol 130 (4) ◽  
pp. 336 ◽  
Author(s):  
Eric A Parkinson ◽  
Chris J Perrin ◽  
Daniel Ramos-Espinoza ◽  
Eric B Taylor
Keyword(s):  
British Columbia ◽  
Fresh Water ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Water Levels ◽  
North Coast ◽  
The North ◽  
Seaward Migration ◽  
Mature Fish

The Coho Salmon, Oncorhynchus kisutch, is one of seven species of Pacific salmon and trout native to northeastern Pacific Ocean watersheds. The species is typically anadromous; adults reproduce in fresh water where juveniles reside for 1–2 years before seaward migration after which the majority of growth occurs in the ocean before maturation at 2–4 years old when adults return to fresh water to spawn. Here, we report maturation of Coho Salmon in two freshwater lakes on the north coast of British Columbia apparently without their being to sea. A total of 15 mature fish (11 males and four females) were collected in two lakes across two years. The mature fish were all at least 29 cm in total length and ranged in age from three to five years old. The occurrence of Coho Salmon that have matured in fresh water without first going to sea is exceedingly rare in their natural range, especially for females. Such mature Coho Salmon may represent residual and distinct breeding populations from those in adjacent streams. Alternatively, they may result from the ephemeral restriction in the opportunity to migrate seaward owing to low water levels in the spring when Coho Salmon typically migrate to sea after 1–2 years in fresh water. Regardless of their origin, the ability to mature in fresh water without seaward migration may represent important adaptive life history plasticity in response to variable environments.

Evidence of chemically mediated population recognition in coho salmon (Oncorhynchus kisutch)

1986 ◽  
Vol 64 (1) ◽  
pp. 84-87 ◽  
Author(s):  
Thomas P. Quinn ◽  
Graeme M. Tolson
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
The Other ◽  
Potential Source ◽  
Source Of Information

To test the hypothesis that population-specific pheromones guide adult salmonids to their natal streams, juvenile and adult coho salmon (Oncorhynchus kisutch) were tested for chemosensory responses in two-choice tanks. Coho salmon from Quinsam and Big Qualicum rivers, British Columbia, Canada, distinguished their own population from the other. Tagging evidence indicates that straying between these two rivers and a third, geographically intermediate river seldom occurs. Thus, population-specific chemicals constitute a potential source of information for homing coho salmon, though their role vis-à-vis imprinted odors from other sources could not be evaluated.

Variation in Body Morphology Among British Columbia Populations of Coho Salmon, Oncorhynchus kisutch

1985 ◽  
Vol 42 (12) ◽  
pp. 2020-2028 ◽  
Author(s):  
Eric B. Taylor ◽  
J. D. McPhail
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Function Analysis ◽  
Oncorhynchus Kisutch ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Coastal Streams ◽  
Morphological Differences ◽  
Median Fins ◽  
Coastal British Columbia

Ten populations of juvenile coho salmon, Oncorhynchus kisutch, from streams tributary to the upper Fraser River, the lower Fraser River, and the Strait of Georgia region were morphologically compared. Juveniles from coastal streams (Fraser River below Hell's Gate and the Strait of Georgia) were more robust (deeper bodies and caudal peduncles, shorter heads, and larger median fins) than interior Juveniles. Discriminant function analysis indicated that juvenile coho could be identified as to river of origin with 71% accuracy. Juvenile coho from coastal streams were less successfully classified as to stream of origin; however, juveniles could be successfully identified as either coastal or interior with 93% accuracy. Juvenile coho from north coastal British Columbia, Alaska, and the upper Columbia system also fitted this coastal and interior grouping. This suggests that a coastwide coastal–interior dichotomy in juvenile body form exists. Three populations (one interior and two coastal) were studied in more detail. In these populations the coastal versus interior morphology was consistent over successive years, and was also displayed in individuals reared from eggs in the laboratory. Adult coho salmon also showed some of the coastal–interior morphological differences exhibited by juveniles. We concluded that the morphological differences between coastal and interior coho salmon are at least partially inherited.

scholarly journals The Effectiveness of Semi-Natural Rearing of Coho Salmon (Oncorhynchus kisutch) at the Nitinat River Hatchery, British Columbia

2014 ◽  
Vol 7 (1) ◽  
pp. 23-28
Author(s):  
Robert Brouwer ◽  
Amanda Ross ◽  
Ian Trepanier ◽  
Ronald W. Tanasichuk
Keyword(s):  
British Columbia ◽  
Survival Rate ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
The Other ◽  
Adult Fish ◽  
Male And Female ◽  
Rearing Method ◽  
Two Phases ◽  
The Cost

We compared: 1) rearing mortality, 2) size at release (mean length), 3) jack, male and female sizes, and 4) jack, female, and adult returns of coho salmon (Oncorhynchus kisutch) from three consecutive brood years reared at the Nitinat River hatchery using a conventional or a semi-natural rearing method. The semi-natural method included feeding restrictions, shading of the rearing ponds, lower rearing temperature and rearing densities, exposure to a predator and a volitional release. We found no significant effects of brood year or rearing method on rearing mortality; it was significantly lower during the marking to release phase than during the other two phases (eyed-egg to ponding, ponding to marking). Conventionally reared smolts were significantly longer. Conventionally reared males were longer. As a proportion of number of smolts released, semi-natural rearing produced 86% fewer jacks, the same proportion of females and 15% more adults. Adult production trends, described as marine survival rate (returning adults • smolt-1) for Nitinat River Hatchery coho, and as ln recruits • female spawner-1 for a nearby wild coho population, were similar. Jacking rates were lower in Nitinat River hatchery coho than for the nearby wild coho population. We concluded that the semi-natural rearing methodology produces adult fish more efficiently than the conventional rearing method does, and at 73% of the cost.

Rhabdochona kisutchi sp. nov. (Nematoda: Spiruroidea) from coho salmon, Oncorhynchus kisutch (Walbaum), of western Canada

1975 ◽  
Vol 53 (7) ◽  
pp. 960-966 ◽  
Author(s):  
L. Margolis ◽  
F. Moravec ◽  
T. E. McDonald
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Nematode Species ◽  
Western Canada ◽  
Pyloric Caeca ◽  
Polar Caps ◽  
Female Tail

A new nematode species, Rhabdochona kisutchi sp. nov., is described from the intestine and pyloric caeca of coho salmon (Oncorhynchus kisutch) smolts from streams of British Columbia, Canada. It differs from all hitherto known members of the genus, except R. sulaki Saidov, 1953, in having eggs provided with polar caps. It can be distinguished from R. sulaki by the shape, origin, and infrequent occurrence of polar filaments; the position of the vulva; and the length of the esophagus and female tail.

Influence of parental stock and incubation temperature on the early development of coho salmon (Oncorhynchus kisutch) in British Columbia

1990 ◽  
Vol 68 (2) ◽  
pp. 347-358 ◽  
Author(s):  
C. B. Murray ◽  
T. D. Beacham ◽  
J. D. McPhail
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Incubation Temperature ◽  
Survival Rates ◽  
Oncorhynchus Kisutch ◽  
Queen Charlotte Islands ◽  
Hatching Time ◽  
Parental Stock ◽  
Queen Charlotte Island ◽  
Developmental Characteristics

Coho salmon (Oncorhynchus kisutch) stocks in British Columbia spawning from October to April were surveyed for variation in developmental characteristics at incubation temperatures from 1.5 to 15 °C. There were no trends in embryo or alevin survival rates associated with spawning time or spawning temperature. The highest embryo and alevin survival rates occurred at 4 or 5 °C and complete mortality generally occurred at 14 or 15 °C. Vancouver and Queen Charlotte Island stocks had lower survival rates at 1.5 and 2 °C than did mainland stocks. Time to 50% hatching and 50% emergence varied inversely with incubation temperature. Alevin hatching time for the Pallant Creek stock on the Queen Charlotte Islands was later than for all other stocks. Stocks had different trends in alevin and fry length and weight with respect to incubation temperature. Northern stocks tended to be more efficient than southern stocks at converting yolk to body tissue at 1.5 and 2 °C, as were mainland stocks compared with island stocks.

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