Behavioral interactions between coho (Oncorhynchus kisutch) and chinook salmon (Oncorhynchus shawytscha) and prey fish species

1997 ◽  
Vol 6 (4) ◽  
pp. 190-195 ◽  
Author(s):  
J. Savitz ◽  
L. Bardygula-Nonn
1993 ◽  
Vol 50 (4) ◽  
pp. 759-766 ◽  
Author(s):  
Kira Salonius ◽  
George K. Iwama

Coho (Oncorhynchus kisutch) and chinook salmon (0. tshawytscha) from aquaculture and wild environments were subjected to handling (30–60 s of netting and aerial emersion) and disease challenges. Plasma cortisol concentrations ([cortisol]pl) in both coho and chinook salmon from wild environments were significantly elevated 4 h after handling. Colonized coho salmon (hatchery-reared fish, transported into a natural water body as fry) responded in a similar fashion to wild fish, while those reared entirely in the hatchery showed no significant rise in [cortisol]pl. The responses to handling stress were retained in wild and colonized coho salmon after 7 mo of hatchery rearing. A transient increase in the leukocyte to red blood cell ratio in both wild and hatchery-reared chinook salmon occurred 4 h after handling. Handling signficantly decreased the antibody-producing cell (APC) number in wild fish and elevated their [cortisol]plrelative to hatchery fish. Wild fish had the highest APC number among the three groups before the handling. No difference in resistance to Vibrio anguillarum was apparent in coho and chinook salmon among the different rearing environments, although chinook salmon were generally more susceptible; disease resistance was reduced in wild coho salmon after 7 mo of rearing in a hatchery.


2014 ◽  
Vol 59 (10) ◽  
pp. 2150-2161 ◽  
Author(s):  
Gord Paterson ◽  
Scott A. Rush ◽  
Michael T. Arts ◽  
Ken G. Drouillard ◽  
Gordon Doug Haffner ◽  
...  

2004 ◽  
Vol 177 (1-2) ◽  
pp. 95-106 ◽  
Author(s):  
Irene Martins ◽  
José Costa Pereira ◽  
Jaime A. Ramos ◽  
Sven Erik Jørgensen

1994 ◽  
Vol 51 (6) ◽  
pp. 1384-1390 ◽  
Author(s):  
Craig A. Stow ◽  
Stephen R. Carpenter ◽  
James F. Amrhein

Lake Michigan coho (Oncorhynchus kisutch) and chinook salmon (O. tshawytscha) PCB concentration data from 1974 to 1990 were examined. The mean and variance of the concentrations exhibited a generally decreasing pattern in each species. Three alternative models, an exponential decay model, a double exponential decay model, and an exponential decay model with a nonzero asymptote, were fit to the data. The double exponential model provided the best fit for both species. Estimated rate coefficients for this model indicated that an early rapid decrease in PCBs has slowed and that PCBs may currently be increasing in coho and chinook salmon. These PCB increases may be the indirect result of a decline in the alewife (Alosa pseudoharengus) forage base that occurred during the 1980s. Parameter estimates from the nonzero asymptote model suggested that PCB levels may not decrease substantially below the current 2 mg/kg FDA action level. Significant decreases of PCB concentrations in coho and chinook salmon may depend on fisheries management practices that promote higher fish growth rates.


1975 ◽  
Vol 32 (9) ◽  
pp. 1648-1652 ◽  
Author(s):  
A. J. Ross ◽  
W. T. Yasutake ◽  
Steve Leek

Phoma herbarum, a fungal plant saprophyte, was isolated from diseased hatchery-reared coho salmon (Oncorhynchus kisutch), chinook salmon (O. tshawytscha), and rainbow trout (Salmo gairdneri). The disease was observed at 10 national fish hatcheries in Washington and Oregon, but the low incidence of experimental infections indicate that it is only weakly contagious. Histopathological examination suggests that the air bladder is one of the primary organs infected. The visceral organs are also affected in both natural and experimental infections.


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