Effect of Stocking Density on the Survival, Growth, and Dispersal of Steelhead Trout Fry (Salmo gairdneri)

1987 ◽  
Vol 44 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Jeremy M. B. Hume ◽  
Eric A. Parkinson
Keyword(s):  
British Columbia ◽  
Overall Survival ◽  
Stocking Density ◽  
Mortality Rates ◽  
Wild Fish ◽  
Density Effect ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Density Dependent ◽  
Coastal British Columbia

In a coastal British Columbia stream a stocking density of between 0.3 and 0.7 fry/m2 maximized the production of steelhead trout (Salmo gairdneri) parr and smolts. A severe autumn flood doubled the mortality rates of fry stocked at densities of 0.7 fry/m2 or higher but had little effect on fry stocked at lower densities (<0.15 fry/m2). Overall survival to smolts appeared to be lower than measured elsewhere for wild fish (2 vs. 4.5 – 18%). The proportion (<10%) of surviving fry found below the stocked sections was considered to be an indicator of potential displacement mortality in streams with no vacant downstream areas. This downstream dispersal was not density dependent and was small in comparison with the mortality of nondispersing fish. Although initial fry and parr sizes were density dependent, there was no detectable density effect on older parr or smolt sizes.

Genetic Variation in Populations of Steelhead Trout (Salmo gairdneri) in British Columbia

1984 ◽  
Vol 41 (10) ◽  
pp. 1412-1420 ◽  
Author(s):  
Eric A. Parkinson
Keyword(s):  
British Columbia ◽  
Genetic Variants ◽  
Large Scale ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Isolated Populations ◽  
Gene Frequencies ◽  
Geographic Scale ◽  
Biochemical Genetic ◽  
Pattern Of Variation

The geographic distributions of biochemical genetic variants at four loci in indigenous British Columbia steelhead (Salmo gairdneri) populations indicated that there was a large-scale subdivision of the species into three major groups. At intermediate geographic scales, gene frequencies were uniform over unexpectedly large areas, but at the smallest geographic scale, significant differentiation was observed between populations in adjacent streams. This pattern of variation supports the view that this species is subdivided into a large number of semi-isolated populations each having the potential to evolve adaptations to local environmental conditions.

Genetic Differences in Growth and Survival of Juvenile Hatchery and Wild Steelhead Trout, Salmo gairdneri

1977 ◽  
Vol 34 (1) ◽  
pp. 123-128 ◽  
Author(s):  
R. R. Reisenbichler ◽  
J. D. McIntyre
Keyword(s):  
Growth Rates ◽  
Genetic Differences ◽  
Wild Fish ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Growth And Survival ◽  
Hatchery Fish ◽  
Natural Streams ◽  
Stock Recruitment ◽  
Relationship Of

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.

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.

Ceratomyxa shasta Noble, 1950 (Myxozoa: Myxosporea) present in the Fraser River system of British Columbia

1983 ◽  
Vol 61 (9) ◽  
pp. 1991-1994 ◽  
Author(s):  
T. E. McDonald
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Drainage Basin ◽  
Coho Salmon ◽  
Cutthroat Trout ◽  
River System ◽  
Salmo Gairdneri ◽  
Fraser River ◽  
Steelhead Trout

An examination of 220 chinook salmon (Oncorhynchus tshawytscha), 84 coho salmon (O. kisutch), 145 steelhead trout (Salmo gairdneri), and 21 cutthroat trout (S. clarki) for Ceratomyxa shasta (Myxozoa: Myxosporea) from 16 localities in the Fraser River drainage, British Columbia, showed that at all sites examined these salmonid species were infected, with a prevalence ranging between 11 and 100%. The study concludes that C. shasta, the causative agent of the salmonid disease ceratomyxosis, is widely distributed in the Fraser drainage basin and discusses these results in relation to proposed fish culture in the region.

Interbreeding with Domestic Strain Increases Foraging under Threat of Predation in Juvenile Steelhead Trout (Oncorhynchus mykiss): An Experimental Study

1991 ◽  
Vol 48 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Jörgen I. Johnsson ◽  
Mark V. Abrahams
Keyword(s):  
Experimental Study ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Foraging Behaviour ◽  
Wild Population ◽  
Mortality Rates ◽  
Wild Fish ◽  
Risk Exposure ◽  
Steelhead Trout ◽  
Safe Area

The foraging behaviour of laboratory-reared juvenile steelhead trout (Oncorhynchus mykiss) and steelhead/domesticated rainbow trout hybrids were compared. In 10 replicate experiments, 10 fish from each strain were allowed to choose between foraging in a safe area or an area containing a predator. The hybrid trout were significantly more willing to risk exposure to the predator than were the steelhead. It was possible that differences in the relative willingness to risk exposure may have reflected differences in their susceptibility to predation. A second experiment measured the susceptibility of these two strains to the predator by simulating standardized encounters between predator and prey. Both strains suffered identical mortality rates and therefore were considered to be equally susceptible to the predator. This experiment confirmed that the hybrid trout were significantly more willing to take risks than the wild steelhead. These results indicate that interbreeding between escaped hatchery and wild fish may have a potentially damaging effect on the wild population.

Role of Off-Channel Ponds in the Life Cycle of Coho Salmon (Oncorhynchus kisutch) and Other Juvenile Salmonids in the Coldwater River, British Columbia

1989 ◽  
Vol 46 (2) ◽  
pp. 232-242 ◽  
Author(s):  
S. Swales ◽  
C. D. Levings
Keyword(s):  
British Columbia ◽  
Oncorhynchus Tshawytscha ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
River Population ◽  
Main Species ◽  
Main River ◽  
Density And Biomass

Off-channel ponds in the upper reaches of the Coldwater River, British Columbia, were major rearing areas for juvenile coho salmon (Oncorhynchus kisutch). Chinook salmon (Oncorhynchus tshawytscha), steelhead trout (Salmo gairdneri), and Dolly Varden char (Salvelinus malma) were generally scarce in the ponds, although they were numerous in the main river. Coho salmon were predominant at "natural" river sites while steelhead trout was the main species at sites with "rip-rap" bank stabilization. Catches of juvenile coho were much lower in the main river than in the ponds where they were the main species, and were more variable in the river. Population density and biomass estimates of juvenile coho in the ponds ranged from 0.100 fish∙m−2 and 1.00 g∙m−2 to 1.00 fish∙m−2 and 5.15 g∙m−2, compared with density estimates of 0.08–0.23 fish∙m−2 in the river. The coho population in the ponds consisted of 0+ and 1+ age-groups in similar proportions, while in the main river the 0+ age-group was much more abundant. The growth rate of coho in the ponds was faster than in the main river, with pond fish reaching mean lengths of 62–79 mm at the end of the first growing season, compared with 53 mm in the main river. Smolt outmigration from the main study pond occurred in late spring with peak outmigration in May and June coinciding with peak river discharge and increasing water temperatures in the main river and pond.

scholarly journals Variability in Life History Characteristics of Steelhead Trout (Salmo gairdneri) Along the Pacific Coast of North America

1966 ◽  
Vol 23 (3) ◽  
pp. 365-393 ◽  
Author(s):  
I. L. Withler
Keyword(s):  
British Columbia ◽  
Pacific Coast ◽  
Salt Water ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Central California ◽  
Late Entry ◽  
Northern Areas ◽  
The Pacific ◽  
Variation Range

Steelhead enter spawning streams in the lower mainland of British Columbia throughout all months. Those ascending streams between November 1 and April 30 are termed "winter steelhead," while "summer steelhead" enter streams between May 1 and September 30. Cheakamus River is exceptional in that initial stream entry of winter steelhead is delayed until April 1, with most fish entering during April and May. Late entry is related to delayed freshet conditions within this stream. Almost twice as many female as male steelhead were angled. Comparison with trapping results suggests that sport fisheries select for females of anadromous rainbow trout populations. Repeat spawning of winter steelhead was found to range from 5.0% for fish from the Seymour River to 31.3% for Cheakamus River. Repeat spawning among summer steelhead ranged from 4.4% (Seymour River) to 6.3% (Coquihalla River). Mean fork lengths of populations of winter and summer steelhead showed little variation (range 26.3–31.0 inches). Winter steelhead from the Cheakamus River were larger than fish from all other populations while summer steelhead from the Coquihalla River had the least mean length. In general, mean fork lengths of winter and summer steelhead were not greatly different, despite the 5–8-month shorter term of saltwater residence of the latter. However, variations in mean lengths of steelhead between different river systems may result from differences in duration of saltwater residence since mean lengths of these populations did increase with longer saltwater residence. Steelhead spent from 1 to 4 years in fresh water and from 1 to 4 years in salt water.Along the Pacific coast from central California to southern British Columbia, timing of initial stream entry showed little variation. Sex ratios were nearly 1:1. Incidence of repeat spawning decreased from south to north. Mean fork lengths of steelhead populations were greater in northern areas where fish spent more years in fresh and more years in salt water.

Influence of the time and rate of liquid-manure application on yield and nitrogen utilization of silage corn in south coastal British Columbia

1996 ◽  
Vol 76 (2) ◽  
pp. 153-164 ◽  
Author(s):  
B. J. Zebarth ◽  
J. W. Paul ◽  
O. Schmidt ◽  
R. McDougall
Keyword(s):  
British Columbia ◽  
Dairy Manure ◽  
Inorganic Fertilizer ◽  
N Recovery ◽  
Corn Yield ◽  
Residual Soil ◽  
Soil Nitrate ◽  
Liquid Manure ◽  
Manure Application ◽  
Coastal British Columbia

Manure-N availability must be known in order to design application practices that maximize the nutrient value of the manure while minimizing adverse environmental impacts. This study determined the effect of time and rate of liquid manure application on silage corn yield and N utilization, and residual soil nitrate at harvest, in south coastal British Columbia. Liquid dairy or liquid hog manure was applied at target rates of 0, 175, 350 or 525 kg N ha−1, with or without addition of 100 kg N ha−1 as inorganic fertilizer, at two sites in each of 2 yr. Time of liquid-dairy-manure application was also tested at two sites in each of 2 yr with N-application treatments of: 600 kg N ha−1 as manure applied in spring; 600 kg N ha−1 as manure applied in fall; 300 kg N ha−1 as manure applied in each of spring and fall; 200 kg N ha−1 applied as inorganic fertilizer in spring; 300 kg N ha−1 as manure plus 100 kg N ha−1 as inorganic fertilizer applied in spring; and a control that received no applied N. Fall-applied manure did not increase corn yield or N uptake in the following growing season. At all sites, maximum yield was attained using manure only. Selection of proper spring application rates for manure and inorganic fertilizer were found to be equally important in minimizing residual soil nitrate at harvest. Apparent recovery of applied N in the crop ranged from 0 to 33% for manure and from 18 to 93% for inorganic fertilizer. Key words: N recovery, manure management

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