Wahleach Project Water Use Plan Lower Jones Creek ... - BC Hydro

4.5.3 Water Temperature and Accumulated Thermal Units
Mean daily water temperatures and accumulated thermal units (ATUs) from September 15,
2008 (start of spawning) to May 14, 2009 (end of emergence) are shown in Figure 8. ATU for
the duration of the trapping program ranged from 731 to 995 (measured from the peak
spawning date of October 6, 2009 to May 15, 2009); the predicted peak emergence period for
chum fry using 900-950 ATU was from April 26 – May 6. This precisely matched the observed
peak, which was April 25 - May 6, (corresponding to between 901-953 ATU’s). The 50% outmigration
completion date for chum fry was April 25, which corresponds to 896 ATU. Water
temperature during the emergence period ranged from 0.01 to 8.3 degrees Celsius.
Temperature Celcius
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29‐Sep
Temperature Celcius
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Lower Jones Creek Fish Productivity Monitoring 2008-2009 20
ATU's
Figure 8 Lower Jones Creek mean daily water temperature and ATUs from the start of chum
spawning (September 22, 2008), to the end of emergence, (May 14, 2009).
4.8 Lorenzetti Creek Trapping Results
The trap on Lorenzetti Creek was in operation from March 26 to April 23, 2009 for a total of 29
days. There were 2,061 chum fry and 123 coho smolts were captured during that period.
Lorenzetta Creek had a much greater diversity of species captured (Table 8) and many more
chum fry over only a portion of the migration period.
Chum fry were captured on 25 of the 29 days that the trap was operating (Figure 9). The first
chum was captured on March 27 (which is the earliest date chum fry have been captured on
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ATU's