scholarly journals Characterizing Juvenile Chinook Salmon Residency and Early Growth in the Lower Fraser River Estuary

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


1984 ◽  
Vol 62 (6) ◽  
pp. 1081-1083 ◽  
Author(s):  
Hilda Lei Ching ◽  
D. R. Munday

Juvenile chinook salmon representing six stocks from the Fraser River drainage system were tested for susceptibility to the myxozoan pathogen, Ceratomyxa shasta. Of the six stocks tested, three were collected from the Nechako, Quesnel, and Clearwater rivers and three were hatchery stocks originating from Slim Creek and the Bowron and Birkenhead rivers. Of 302 fish exposed in August 1982, 95% became infected and died of ceratomyxosis. Susceptibility was high and time of death varied with the fish stock. High river temperatures during the 10 days of exposure and a high level of abundance of infectious C. shasta contributed to high mortalities of fish. Results of maintenance of infected fish in seawater indicated that ceratomyxosis is not attenuated and fish will continue to die after entering the estuarine environment.


2013 ◽  
Vol 97 (6) ◽  
pp. 731-740 ◽  
Author(s):  
Thomas P. Quinn ◽  
J. Anne Shaffer ◽  
Justin Brown ◽  
Nicole Harris ◽  
Chris Byrnes ◽  
...  

1986 ◽  
Vol 43 (7) ◽  
pp. 1386-1397 ◽  
Author(s):  
C. D. Levings ◽  
C. D. McAllister ◽  
B. D. Chang

From March 1982 to December 1983, juvenile chinook salmon (Oncorhynchus tshawytscha) were sampled by beach-seine in the Campbell River estuary and adjacent waters of Discovery Passage in order to examine estuarine use by wild and hatchery stocks. Wild juvenile chinook entered the estuary as migrant fry and were present in the estuarine zone mainly in late April to June, in the transition zone in mid-May to July, and in the marine zone in July. Hatchery fish were released from early May to early July. Maximum catches of wild stocks were similar in the estuarine and transition zones, while the maximum catches of most hatchery stocks were higher in the transition zone. For both wild and hatchery chinook, catches in the marine zone were much lower than in the estuarine and transition zones. Wild fry resided in the estuary for 40–60 d, while most hatchery fish used the estuary for about one-half this period. Wild stocks showed a relatively constant rate of increase in mean size from May to September. Higher rates of increase in the mean size of hatchery fish were shown by groups with earlier release dates and smaller mean sizes. Residency time and growth rates for wild fish were comparable with those observed in an estuary without hatchery fish. Potential for interaction between wild and hatchery stocks was greatest in the transition zone, where hatchery fish were most abundant and because hatchery releases occurred when catches of wild fish were highest in this foreshore area.


1988 ◽  
Vol 23 (1) ◽  
pp. 100-113 ◽  
Author(s):  
I. H. Rogers ◽  
J. A. Servizi ◽  
C. D. Levings

Abstract Juvenile chinook salmon were sampled from August 1986 to March 1987 at stations near Prince George and Quesnel, influenced by sewage and pulp mill discharges. Maximum densities of 0.2 fish·mࢤ2 were recorded. Salmon were collected at reference sites in November 1986 and at Agassiz in April 1987. Fingerling chinook were exposed at 0.7°C to a commercial wood preservative containing 2,3,4,6 - tetrachlorophenol (TeCP) and pentachlorophenol (PCP) in the laboratory to simulate winter conditions in the upper Fraser River. Fish exposed for 62 days to 2 ug·Lࢤ1 contained a mean of 224 ng·gࢤ1 TeCP and 431 ng·gࢤ1 PCP. Chlorophenol uptake in feral fish was low. However, 3,4,5-trichloro-guaiacol levels to 304 ng·gࢤ1 and tetrachloroguaiacol values to 136 ng·gࢤ1 were measured in March. Fish from Agassiz, 518 km downstream of Quesnel, also contained these two substances. Thus chinook salmon can bioconcentrate persistent chlorophenols and chloroguaiacols directly from cold water (< 1°C). The biological consequences are uncertain.


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