scholarly journals Variation in Out-migration Timing and Estuary Reliance of “ocean-type” Chinook Salmon in the Fraser River Estuary, BC

2019 ◽  
pp. 25-27
Author(s):  
David Scott ◽  
Lia Chalifour ◽  
Misty MacDuffee ◽  
Julia Baum ◽  
Scott Hinch
1986 ◽  
Vol 43 (3) ◽  
pp. 565-573 ◽  
Author(s):  
Eric B. Taylor ◽  
P. A. Larkin

In Slim Creek, a tributary to the upper Fraser River east of Prince George, B.C., chinook salmon (Oncorhynchus tshawytscha) fry summer and overwinter in their natal stream before migrating seaward as yearlings; they are "stream-type" in juvenile life history pattern. From the Harrison River, a tributary to the lower Fraser River, chinook fry migrate to the Fraser River estuary sometime during their first spring or early summer; they are "ocean-type." Newly emerged chinook fry from Slim Creek showed a stronger positive current response, were more aggressive in mirror image stimulation tests and intra- and inter-specific (with coho salmon (O. kisutch) fry) stream tank tests, and had larger and more brightly colored median fins than chinook fry from the Harrison River. These differences between Slim Creek and Harrison River chinook fry are in a direction consistent with their different patterns of length of freshwater residence as juveniles, since aggressive behavior, positive rheotaxis, and bright fin coloration are important components of extended stream residence in salmonids.


1985 ◽  
Vol 63 (7) ◽  
pp. 1737-1740 ◽  
Author(s):  
Susan M. Bower

Ceratomyxa shasta (mainly trophozoites) from the intestinal tract of a naturally infected juvenile chinook salmon (Oncorhynchus tshawytscha) developed in the coelom of laboratory-reared chinook salmon when inoculated intraperitoneally. All developmental stages were observed. Successful subpassages were accomplished by intraperitoneal inoculation of trophozoites and sporoblasts, but an infection did not develop when these stages were pipetted into the esophagus of susceptible fish. Heavy infections, including the presence of C. shasta sporoblasts or spores, were observed in 2 of 28 feral juvenile chinook salmon seined from the Fraser River estuary in late July and early August. Trophozoite-like cells were observed in six other chinook salmon from this group. No C. shasta were observed in 15 juvenile sockeye salmon (Oncorhynchus nerka) caught in the estuary along with the chinook salmon.


2019 ◽  
pp. 13-15
Author(s):  
Lia Chalifour ◽  
David Scott ◽  
Misty MacDuffee ◽  
John Dower ◽  
Terry Beacham ◽  
...  

1988 ◽  
Vol 23 (1) ◽  
pp. 55-68 ◽  
Author(s):  
J. H. Carey ◽  
J. H. Hart

Abstract The identity and concentrations of chlorophenolic compounds in the Fraser River estuary were determined under conditions of high and low river flow at three sites: a site upstream from the trifurcation and at downstream sites for each main river arm. Major chlorophenolics present under both flow regimes were 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), pentachlorophenol (PCP), tetrachloroguaiacol (TeCG) and a compound tentatively identified as 3,4,5-trichloroguaiacol (3,4,5-TCG). Under high flow conditions, concentrations of the guaiacols were higher than any of the Chlorophenols and concentrations of all five chlorophenolics appeared to correlate. Under low flow conditions, concentrations of chloroguaiacols were higher than Chlorophenols at the upstream site and at the downstream site on the Main Arm, whereas at the downstream site on the North Arm, concentrations of 2,3,4,6-TeCP and PCP were higher than the chloroguaiacols in some samples. Overall, the results indicate that pulp mills upstream from the estuary are important sources of chlorophenolics to the estuary under all flow conditions. Additional episodic inputs of 2,3,4,6-TeCP and PCP from lumber mills occur along the North Arm. When these inputs occur, they can cause the concentrations of Chlorophenols in the North Arm to exceed provisional objectives. If chloroguaiacols are included as part of the objective, concentrations of total chlorophenolics in water entering the estuary can approach and exceed these objectives, especially under low flow conditions.


2002 ◽  
Vol 114 (4) ◽  
pp. 485-490 ◽  
Author(s):  
ROBERT W. BUTLER ◽  
PHILIPPA C. F. SHEPHERD ◽  
MOIRA J. F. LEMON

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