The use of a real-time PCR primer/probe set to observe infectivity of Yersinia ruckeri in Chinook salmon, Oncorhynchus tshawytscha (Walbaum), and steelhead trout, Oncorhynchus mykiss (Walbaum)

2011 ◽  
Vol 34 (10) ◽  
pp. 783-791 ◽  
Author(s):  
R A Glenn ◽  
P W Taylor ◽  
K C Hanson
1991 ◽  
Vol 48 (11) ◽  
pp. 2083-2094 ◽  
Author(s):  
John D. Morgan ◽  
George K. Iwama

Rainbow and steelhead trout (Oncorhynchus mykiss) and fall chinook salmon (Oncorhynchus tshawytscha) fry were acclimated to a range of salinities to test the hypothesis that the energy requirements for ion regulation would be minimal at an isotonic water salinity (8–10 ppt). Survival, growth, metabolic rate, plasma Na+ and Cl− concentrations, and seawater adaptability were measured for 5–12 wk, depending on the species. Growth of all three species was highest in fresh water and declined with increasing salinity. Metabolic rates increased with salinity and were inversely correlated with growth rates. Isotonic salinity, therefore, did not offer significant metabolic or growth advantages to rainbow, steelhead, and chinook fry. While plasma Na+ and Cl− concentrations varied among groups, chinook fry tended to better maintain ionic homeostasis at higher salinities than the trout. Acclimation to the various dilute salinities did not influence the seawater adaptability of juvenile steelhead trout or chinook salmon. Our results indicate that optimal salinities for growth and metabolic rates were influenced by species and life history stage. The metabolic rate data suggested that the energetic cost of ionic regulation increased with salinity, but attempts to quantify this cost were probably affected by other metabolic processes which responded to changes in salinity.


2012 ◽  
Vol 96 (2-3) ◽  
pp. 273-286 ◽  
Author(s):  
Eric D. Chapman ◽  
Alex R. Hearn ◽  
Cyril J. Michel ◽  
Arnold J. Ammann ◽  
Steven T. Lindley ◽  
...  

2015 ◽  
Vol 78 (4) ◽  
pp. 855-858 ◽  
Author(s):  
DONG-HYEON KIM ◽  
JUNG-WHAN CHON ◽  
HONG-SEOK KIM ◽  
JIN-HYEOK YIM ◽  
HYUNSOOK KIM ◽  
...  

Lactobacillus kefiranofaciens is an indicator microorganism for kefir and a key factor in kefir grain formation and kefiran production. We designed a novel real-time PCR primer and probe set, LKF_KU504, for the rapid detection of L. kefiranofaciens. In inclusivity and exclusivity tests, only 14 L. kefiranofaciens strains were positive among 61 microorganisms, indicating 100% sensitivity and specificity. The LKF_KU504 set also differentiated kefir milk from 30 commercial nonkefir yogurts. The levels of L. kefiranofaciens in kefir grain and kefir milk were significantly different, indicating L. kefiranofaciens was more concentrated in kefir grain than in kefir milk.


2011 ◽  
Vol 68 (9) ◽  
pp. 1615-1624 ◽  
Author(s):  
George P. Naughton ◽  
Matthew L. Keefer ◽  
Tami S. Clabough ◽  
Michael A. Jepson ◽  
Steven R. Lee ◽  
...  

Increasing pinniped abundance in the Pacific Northwest has coincided with population declines of Pacific salmon ( Oncorhynchus  spp.) and steelhead trout ( Oncorhynchus mykiss ), and concentrated predation may affect the recovery of some threatened and endangered salmonid stocks. We used radiotelemetry to evaluate pinniped-caused injury effects on migration survival of 17 007 adult Columbia River Chinook salmon ( Oncorhynchus tshawytscha ) and steelhead trout. Injuries from pinnipeds were common (mean injury rate across 29 run-years = 36.5%) and were most common for spring Chinook salmon and steelhead trout. Injury was not consistently associated with adult survival to spawning tributaries, but some negative survival effects were detected. Pinniped-caused injury rates decreased as annual run sizes increased, indicating density-dependent or saturation effects. Within a run, large fish generally had a higher injury incidence than small fish, suggesting pinnipeds targeted large fish or more efficiently captured small fish. Seasonal, size-dependent, and density-dependent results imply that pinniped effects likely differ widely among salmonid populations within the Columbia River basin. A better understanding of these effects is needed to guide management and conservation strategies.


2001 ◽  
Vol 58 (2) ◽  
pp. 365-374 ◽  
Author(s):  
Michael J Bradford ◽  
Paul S Higgins

Juvenile salmonids that live in streams are sometimes nocturnal and may spend the day concealed in the stream substrate. We observed the diel activity patterns of juvenile chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) in two areas of the Bridge River, British Columbia, in all four seasons. In a reach with higher flows, most fish were nocturnal year-round, and they emerged from the substrate only at dusk to forage. In the reach with lower flows, some fish were active in the water column in the day in summer, but others remained concealed in the substrate until dusk. Parr and older fish were more nocturnal in summer than fry. All fish were nocturnal in winter. Because our study design controlled for temperature and photoperiod, we concluded that the differences in behaviour that we observed between reaches were due to habitat conditions that likely affected the trade-off between more risky daytime foraging and less efficient, but safer, nighttime foraging. Habitat-driven variation in activity patterns will likely affect the processes that regulate these populations and could make the prediction of the effects of ecosystem manipulations such as changes in flow very difficult.


1992 ◽  
Vol 70 (7) ◽  
pp. 1341-1346 ◽  
Author(s):  
John D. Morgan ◽  
John O. T. Jensen ◽  
George K. Iwama

Metabolic rates, hatching success, alevin survival, time to hatch, and growth were measured for steelhead (Oncorhynchus mykiss) and fall chinook salmon (Oncorhynchus tshawytscha) embryos incubated in salinities of 0, 4, 8, and 12 parts per thousand (ppt) from the eyed stage. Metabolic rates of eyed steelhead trout eggs, and chinook salmon eggs and alevins were not significantly affected by the salinities tested. The metabolic rate of newly hatched steelhead trout alevins, however, was significantly lower in 8-ppt, and significantly higher in 12-ppt, than in 0- and 4-ppt salinities. Egg hatchability was high in all four salinities, but newly hatched alevins of both species showed decreased survival and were smaller in 12-ppt salinity. Salinity effects on alevin survival and size were greater for steelhead trout than for chinook salmon. The results suggest that 8-ppt salinity is the upper limit for the normal development of steelhead trout and chinook salmon eggs and alevins.


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