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.

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.

Fecundity of coho salmon (Oncorhynchus kisutch) and chum salmon (O. keta) in the northeast Pacific Ocean

1982 ◽  
Vol 60 (6) ◽  
pp. 1463-1469 ◽  
Author(s):  
Terry D. Beacham
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Vancouver Island ◽  
Northeast Pacific ◽  
Queen Charlotte Islands ◽  
Kodiak Island ◽  
Salmon Stock ◽  
Northeast Pacific Ocean

Significant regional and annual variability in fecundity of coho salmon (Oncorhynchus kisutch) and chum salmon (O. keta) in British Columbia was detected during this investigation. A Kodiak Island (Alaska) coho salmon stock was more fecund than southern stocks in British Columbia and Washington. Fecundity ranged from 2450 to 2850 eggs per female at 53.6 cm postorbital–hypural length for Vancouver Island stocks to over 4400 eggs per female for a Kodiak Island stock at the same length. Chum stocks on Vancouver Island and the Queen Charlotte Islands generally had fecundities less than 3200 eggs per female at 58.8 cm postorbital–hypural length, whereas chum of equal lengths in mainland British Columbia stocks ranged from 3200 to 3450 eggs per female. Older chum and coho were usually more fecund than younger ones, but this difference could be accounted for by differences in mean length-at-age, fecundity being related to body size.

Straying Patterns of Coho Salmon (Oncorhynchus kisutch) Stock from Southeast Vancouver Island, British Columbia

1992 ◽  
Vol 49 (9) ◽  
pp. 1843-1855 ◽  
Author(s):  
M. Labelle
Keyword(s):  
British Columbia ◽  
Selective Breeding ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Vancouver Island ◽  
Water Sources ◽  
Adult Age ◽  
Hatchery Fish ◽  
Genetic Makeup ◽  
Average Adult

Fourteen coho salmon (Oncorhynchus kisutch) stocks of wild and hatchery origin were tagged from 1985 to 1988 in nine streams within a 150-km coastal section of Vancouver Island. Tag escapements to natal streams were estimated from fence counts, stream surveys, and mark–recapture operations. On average, adult (age 3+) strays accounted for ~4.7% of escapements, but for > 40% of the adult escapements in some cases. Adult straying rate, averaged across all years and stocks, was < 2%. Straying rates tended to be lower for hatchery fish and highest for stocks subjected to certain enhancement practices. Adult strays escaped to streams 2–159 km from their home stream (average 15.7 km); over 50% escaped to streams < 7 km from their stream of release. Straying rates of jacks (age 2+) in a given year and that of their adult siblings during the following year were not related. Genetic makeup, age-at-return, run timing, and exposure to nonnatal water sources during the rearing stage did influence homing. Changes in natural straying patterns should be suspected where enhancement measures include flow controls, selective breeding, and exposure of fry to various water sources. Straying levels and stray contributions should be considered when estimating survival and exploitation rates

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.

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