Saltwater Exposure at Fertilization Induces Ploidy Alterations. Including Mosaicism, in Salmonid

1994 ◽  
Vol 51 (S1) ◽  
pp. 42-49 ◽  
Author(s):  
Gary D. Miller ◽  
James E. Seeb ◽  
Brian G. Bue ◽  
Samuel Sharr
Keyword(s):  
Flow Cytometry ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Chromosome Segregation ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Salt Water ◽  
Pink Salmon ◽  
Flow Cytometry Analysis ◽  
Rainbow Trout Oncorhynchus Mykiss

We found that salt water induces ploidy alterations in salmonid embryos. Flow cytometry analysis revealed significantly higher frequencies of haploids, triploids, heteroploid mosaics, and aneuploids in rainbow trout (Oncorhynchus mykiss) embryos experimentally exposed to salt water from fertilization to the two- and eight-cell stages of development. Heteroploid mosaics have been reported in diploid and triploid salmonid hybrids, although none were observed in the triploid coho salmon or diploid and triploid coho salmon (O. kisutch) × chinook salmon (O. tshawytscha) hybrids we examined. No mosaics were observed in intertidally spawned pink salmon (O. gorbuscha) embryos. Salt water could induce ploidy alterations by causing chromosome segregation errors during meiosis, mitosis, or both. Heteroploid embryos appeared morphologically normal although they may possess physiological deficiencies not immediately apparent.

The effects of domestication on the relative vulnerability of hatchery and wild origin spring Chinook salmon (Oncorhynchus tshawytscha) to predation

2007 ◽  
Vol 64 (5) ◽  
pp. 813-818 ◽  
Author(s):  
Anthony L Fritts ◽  
Jennifer L Scott ◽  
Todd N Pearsons
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Chinook Salmon ◽  
First Generation ◽  
Oncorhynchus Tshawytscha ◽  
State Of The Art ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Salmon Fry ◽  
History Of ◽  
Relative Vulnerability

We tested whether one generation of state-of-the-art hatchery culture influenced the vulnerability of Chinook salmon (Oncorhynchus tshawytscha) fry to predators. Size-matched hatchery and wild origin spring Chinook salmon fry were exposed to rainbow trout (Oncorhynchus mykiss) and torrent sculpin (Cottus rhotheus) predators in 10.8 m3 net pens. The hatchery origin fry were the offspring of first generation hatchery-reared broodstock, and the wild origin fry had no history of hatchery culture; both originated from the same stock. Wild origin fry were found to have a 2.2% (p = 0.016) survival advantage over hatchery origin fry during 2 years of predation challenges. The most important findings of this study are (i) domestication can affect the susceptibility to predators after only one generation of state-of-the-art hatchery culture practices, and (ii) the domestication effect was very small.

Hybridization with Domesticated Rainbow Trout (Oncorhynchus mykiss) Reduces Seasonal Variation in Growth of Steelhead Trout (O. mykiss)

1993 ◽  
Vol 50 (3) ◽  
pp. 480-487 ◽  
Author(s):  
Jörgen I. Johnsson ◽  
W. Craig Clarke ◽  
Ruth E. Withler
Keyword(s):  
Growth Rate ◽  
Seasonal Variation ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Natural Waters ◽  
Salt Water ◽  
Feeding Activity ◽  
Steelhead Trout ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Winter Conditions

We tested the hypothesis that hybridization with domesticated rainbow trout (Oncorhynchus mykiss) reduces the seasonal variation in growth in both fresh and salt water in anadromous steelhead trout (O. mykiss). The seasonal variation in freshwater growth was more pronounced in the steelhead trout than in the hybrid and domesticated trout. Consequently, differences in growth rate among groups were considerably higher during winter than in fall or spring. We suggest that high feeding activity during unfavourable winter conditions in natural waters is maladaptive, but is not selected against in protected hatchery environments with a continuous food supply. This may lead to genetic divergence in feeding physiology and/or behaviour between steelhead trout and domesticated rainbow trout. Growth rates in experimental groups transferred to seawater in December relative to groups transferred in April were faster in rainbow and hybrid trout than in steelhead trout. The results support the hypothesis that seasonal variation in seawater growth in steelhead trout is reduced by crossing with domesticated rainbow trout.

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