A Small RNA Virus Isolated from Salmonid Fishes in California, USA

1991 ◽  
Vol 48 (1) ◽  
pp. 99-104 ◽  
Author(s):  
R. P. Hedrick ◽  
S. Yun ◽  
W. H. Wingfield
Keyword(s):  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Coho Salmon ◽  
Rna Virus ◽  
Juvenile Fish ◽  
Cutthroat Trout ◽  
Kokanee Salmon ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Tissue Homogenates

Beginning in the summer of 1988, examinations of numerous salmonid broodstocks in northern California, USA, revealed widespread infections with a previously undescribed virus. The virus was isolated from ovarian fluids of adult rainbow trout (Oncorhynchus mykiss), cutthroat trout (O. clarki), brown trout (Salmo trutta), and brook trout (Salvelinus fontinalis) and from kidney and spleen samples of juvenile brown and brook trout. The virus was not associated with above-normal losses in adult or juvenile fish. Virions purified from infected CHSE-214 cells were hexagonal with a mean diameter of 37.5 nm (SD = 0.41) and did not possess an envelope. The virus induced a diffuse degenerative cytopathic effect in CHSE-214 cells 14–28 d after inoculation with ovarian fluids or tissue homogenates. The virus replicated in CHSE-214 cells at temperatures from 10 to 20 °C with an optimum at 15 °C. Replication of the virus was not inhibited by addition of 5-bromo-2-deoxyuridine (BUDR) to the growth medium. There was no virus-induced mortality but virus was recovered for periods of up to 3–5 wk following waterborne exposures of rainbow and brown trout and kokanee salmon (O. nerka) but not from chinook (O. tshawytscha) or coho salmon (O. kisutch).

Trends in the Distribution and Abundance of Yellowstone Cutthroat Trout and Nonnative Trout in Idaho

2014 ◽  
Vol 5 (2) ◽  
pp. 227-242 ◽  
Author(s):  
Kevin A. Meyer ◽  
Erin I. Larson ◽  
Christopher L. Sullivan ◽  
Brett High
Keyword(s):  
Rainbow Trout ◽  
River Basin ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Cutthroat Trout ◽  
Snake River ◽  
Trout Population ◽  
Yellowstone Cutthroat Trout ◽  
Over Time

Abstract The distribution and abundance of Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri across their native range is relatively well-known, but evaluations of trends in distribution and abundance over time are lacking. In 2010–2011, we resurveyed 74 stream reaches in the upper Snake River basin of Idaho that were sampled in the 1980s and again in 1999–2000 to evaluate changes in the distribution and abundance of Yellowstone cutthroat trout and nonnative trout over time. Yellowstone cutthroat trout occupied all 74 reaches in the 1980s, 70 reaches in 1999–2000, and 69 reaches in 2010–2011. In comparison, rainbow trout O. mykiss and rainbow × cutthroat hybrid occupancy increased from 23 reaches in the 1980s to 36 reaches in 1999–2000, and then declined back to 23 reaches in 2010–2011. The proportion of reaches occupied by brown trout Salmo trutta and brook trout Salvelinus fontinalis was largely unchanged across time periods. Yellowstone cutthroat trout abundance declined from a mean of 40.0 fish/100 linear meters of stream in the 1980s to 32.8 fish/100 m in 2010–2011. In contrast, estimates of abundance increased over time for all species of nonnative trout. Population growth rate (λ) was therefore below replacement for Yellowstone cutthroat trout (mean  =  0.98) and above replacement for rainbow trout (1.07), brown trout (1.08), and brook trout (1.04), but 90% confidence intervals overlapped unity for all species. However, λ differed statistically from 1.00 within some individual drainages for each species. More pronounced drought conditions in any given year resulted in lower Yellowstone cutthroat trout abundance 1 y later. Our results suggest that over a span of up to 32 y, the distribution and abundance of Yellowstone cutthroat trout in the upper Snake River basin of Idaho appears to be relatively stable, and nonnative trout do not currently appear to be expanding across the basin.

scholarly journals Fishery-exteriors characteristics of the brooders of brown trout, rainbow trout and brook trout

2019 ◽  
Vol 21 (90) ◽  
pp. 88-92
Author(s):  
Ye. O. Barylo ◽  
Yu. V. Loboiko ◽  
B. S. Barylo
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Salvelinus Fontinalis ◽  
Condition Factor ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Brown Trout Salmo Trutta ◽  
Relative Fertility

This study aims to determine the reproductive indices of three types of salmon fish: brown trout (Salmo trutta morfa fario Linnaeus (1758), rainbow trout (Oncorhynchus mykiss Walbaum, 1792) and brook trout (Salvelinus fontinalis Mitchill, 1814) in aquaculture. For this purpose, 10 females and 10 males of each species were selected on an analogous basis and the main fishery-exteriors and reproductive characteristics were identified. The researching of relative fertility permit to establish that this indicator in brook trout females was 18.36% higher compared to rainbow trout, however, by 7.5% lower compared to the brown trout. It was found that brook trout eggs had less weight and size in comparison with other studied species. In particular, the weight and diameter of the eggs were 2.89 and 9.7% respectively lower than of rainbow trout, as well as 8.1 and 3.44% respectively lower compared to the brown trout. When studying the quantity of ejaculate, it was found that on average, brook trout males had 16.95% less of ejaculates compared to rainbow trout males, but 79.6% more than of brown trout males. When comparing the main indices of the brooders body of the studied species, it was found that the condition factor of the brook trout and rainbow trout females was quite high at 1.55–1.57, the brown trout one was 1.35, and the profile index respectively was 3.5, 3.52 and 4.0. The males' condition factor of brook trout, rainbow trout and brown trout was respectively 1.64, 1.52 and 1.35. Fishery-exteriors indicators met the requirements of brooders species and age specificity norms of the studied fish species.

scholarly journals Assessment of trout populations inhabiting the Palena River, southern Chile

2021 ◽  
Vol 49 (1) ◽  
pp. 29-39
Author(s):  
Sandra Bravo ◽  
Ken Whelan ◽  
María Teresa Silva
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Salvelinus Fontinalis ◽  
Feeding Habits ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Recreational Angling ◽  
Brown Trout Salmo Trutta ◽  
Gravid Females

A survey of trout species was carried out to assess the trout stocks' quality inhabiting the Palena River Basin, one of the most important rivers for recreational angling in Chilean Patagonia. Six sampling campaigns were carried out over 16 selected stretches of the river between February 2012 and June 2013. A total of 912 trout were collected, 57% rainbow trout (Oncorhynchus mykiss), 33.3% brown trout (Salmo trutta), and 9.6% brook trout (Salvelinus fontinalis). Also, one tiger trout (Salmo trutta × Salvelinus fontinalis) (a hybrid between brown and brook trout) was recorded. Results showed that both rainbow trout and brown trout shared the same reaches of the river, with very similar feeding habits, while brook trout inhabited smaller and more enclosed streams. Maturity stages (V-VI) were recorded from the fish sampled over the period spring-summer-autumn in the case of rainbow trout; autumn-winter for brook trout, and summer-autumn for brook trout. One of the study's most notable features was the small size of the mature brook trout, reaching 17.5 cm in length for gravid females and 12.4 cm for mature males at age 2+. The maximum age recorded for rainbow and brown trout was 6+, with a maximum length of 69.8 and 58.5cm, respectively, while for brook trout, the maximum age recorded was 3+ for a female with a length of 29.9 cm length and 2+ for a male of 16.6 cm.

Effects of Fish Introductions and Hydroelectric Development on Fishes in the Kananaskis River System, Alberta

1965 ◽  
Vol 22 (3) ◽  
pp. 721-753 ◽  
Author(s):  
J. S. Nelson
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Cutthroat Trout ◽  
River System ◽  
Hydroelectric Development ◽  
Fish Introductions ◽  
Longnose Suckers ◽  
Abundance And Distribution

Changes occurred in the abundance and distribution of fishes in the Kananaskis River system, Alberta, in conjunction with fish introductions and hydroelectric development. Data from surveys from 1936 to 1961 indicate the probable chronology of events.Dolly Varden (Salvelinus malma), brook trout (S. fontinalis), cutthroat trout (Salmo clarkii), and rainbow trout (S. gairdneri) decreased in abundance, probably due to the introduction of brown trout (Salmo trutta), longnose suckers (Catostomus catostomus), and white suckers (C. commersonii), to the cooling of the Kananaskis River from reservoir construction, and to sport fishing. Hybridization between rainbow and cutthroat trout was also important in the decrease of the latter species. After introduction by man, brown trout, rainbow trout, longnose suckers, white suckers, lake chub (Hybopsis plumbea), and longnose dace (Rhinichthys cataractae) greatly increased in abundance. Prior to the increase in numbers of white suckers, a reduction in the numbers of longnose suckers occurred in Lower Kananaskis Reservoir. Little change in the distribution of mountain whitefish (Prosopium williamsoni), longnose dace, and brook sticklebacks (Culaea (= Eucalia) inconstans) occurred over the 25 years. Changes in the physicochemical environment and invertebrate fauna in the reservoirs appeared to be of secondary importance to the interaction among fish in causing the changes in species abundance and distribution.

An examination of the PCB: lipid relationship among individual fish

1997 ◽  
Vol 54 (5) ◽  
pp. 1031-1038
Author(s):  
C A Stow ◽  
L J Jackson ◽  
J F Amrhein
Keyword(s):  
Salmo Trutta ◽  
Lake Michigan ◽  
Oncorhynchus Tshawytscha ◽  
Lake Trout ◽  
Coho Salmon ◽  
Salvelinus Namaycush ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Strong Linear Correlation ◽  
Brown Trout Salmo Trutta ◽  
The Relationship

We examined data from 1984 to 1994 for five species of Lake Michigan salmonids to explore the relationship between total PCB concentration and percent lipid. When we compared mean species lipid and PCB values, we found a strong linear correlation. When we compared values among individuals, we found modest positive PCB:lipid associations in brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), and rainbow trout (Oncorhynchus mykiss) collected during spawning, but positive associations were not apparent among nonspawning individuals. Lake trout (Salvelinus namaycush) exhibited no discernible PCB:lipid relationship. Our results are not incompatible with previous observations that contaminants are differentially partitioned into lipids within a fish, but these results do suggest that lipids are not a major factor influencing contaminant uptake.

Unidirectional Natural Hybridization between Brown Trout (Salmo trutta) and Atlantic Salmon (S. salar) in Newfoundland

1992 ◽  
Vol 49 (9) ◽  
pp. 1953-1958 ◽  
Author(s):  
Colin McGowan ◽  
William S. Davidson
Keyword(s):  
Atlantic Salmon ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Dna Analysis ◽  
Juvenile Fish ◽  
Natural Hybridization ◽  
Major Influence ◽  
Isolating Mechanisms ◽  
Brown Trout Salmo Trutta ◽  
Sexually Mature

Protein electrophoresis and mitochondrial DNA analysis were used to detect the frequency and direction of natural hybridization between brown trout (Salmo trutta) and Atlantic salmon (S. salar) in nine Newfoundland rivers. In total, 37 hybrids were discovered in a sample of 792 juvenile fish for a regional frequency of 4.67%. Local frequencies ranged from 0.00 to 18.75% and were significantly heterogeneous. All of the hybrids sampled were produced from matings between female brown trout and male Atlantic salmon. Possible reasons for the breakdown of prereproductive isolating mechanisms between these species are considered. Reproductive characteristics of the populations involved appear to have a major influence on the dynamics of hybridization between these species in Newfoundland. It is proposed that an abundance of sexually mature Atlantic salmon parr in Newfoundland streams is responsible for both the frequency and direction of hybridization observed in this study.

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