Fishing in British Columbia > Members' Fishing Reports

Alouette Lake March 23, 2017

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sbc hris:
Do they still fertilize the lake? If not, that could have an awful lot to do with it as well...

typhoon:

--- Quote from: wildmanyeah on March 29, 2017, 11:10:30 AM ---"In 2007 there is estimated to be between 70,000 to 90,000 sockanee that traveled over the spillway on their way to the Pacific Ocean"

"The Rotary Trap was be installed at Mud Creek to count Kokanee “sockanee” escapement which preliminary numbers show to be approximately 70,000. "

These smolts would of otherwise stayed in the lake and grew up to be Kokanee. I don't have concrete evidence that releasing 70K smolts from the lake each year reduced the numbers of Kokanee in the lake but I know a few people in the area that worked with the project that contribute it to the reduced number of kokanee in the lake.

--- End quote ---

Figure 9 in this report shows that there were fewer 2-3 yr old fish in the lake in 2007, but those number recovered nicely. In 2012 the numbers were almost 6x higher than in 2006 (before the large escapement). 
https://www.bchydro.com/content/dam/BCHydro/customer-portal/documents/corporate/environment-sustainability/water-use-planning/lower-mainland/alumon-6-yr5-2014-03-01.pdf

They are still fertilizing the lake, but the impact to fish size has diminished as shown in Figure 7. The average size has reduced to pre-fertilization levels.
There seem to be other factors at play.

wildmanyeah:
"Spillway releases from the dam during the spring have occurred since 2005 and were
implemented to determine the volitional migration success of O. nerka from the reservoir
(Mathews et al., 2013). It is suspected that spillway releases have the potential to impact to the
kokanee population due to the high proportion of age 1 fish that emigrate. An average of
~17,000 nerkids per year has emigrated from ALR since 2005, not a small number if the
reservoir estimates are anywhere near correct (Plate et al., 2014). However, as previously
discussed, there is the possibility that a compensatory benefit in growth and survival from the
annual loss of kokanee from the reservoir. These potential benefits may provide the ability of
regulatory agencies (MOE and DFO) to meet the management objectives for the restoration of
the ALR and the Alouette River Sockeye Re-Anadromization Project (Plate et al., 2014)."

Also saying that by releasing smolts may increase survival rates and size seems sketchy too when you then go and stock the lake with rainbow!

seems very unclear for sure, still my dream is to see a fishway past the dam!

http://www.gofishbc.com/Stocked-Fish/Detailed-Report.aspx?region=LOWER%20MAINLAND&town=MAPLE%20RIDGE&waterbody=ALOUETTE&start=3/29/2007&end=3/29/2017

RalphH:
Re-establishing some anadromous fish runs above the dam would be quite an achievement.The kokanee population in Alouette never offered much of a fishery until the fertilization project produced some increase in both numbers and size but that seems to have been temporary effect.

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