| Genetic Work on Steelhead:
CRAA worked with Pete Addison and MNR's Chris Wilson to look at the difference of wild and hatchery origin Credit River steelhead. The 2005-06 study found that wild steelhead have diverged from Normandale hatchery steelhead, but have very similar traits to wild Ganaraska steelhead.
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This comes as little surprise as MNR stocked steelhead have been able to spawn and intermingle with wild steelhead on the Credit River fully prior to 2005. As a result of this study CRAA initiated our adult wild steelhead transfer program where we transfer wild steelhead to the prime spawning waters available to the specie, while hatchery steelhead (with fin clips) are released to spawn below Norval. This wild selection process began in 2005 and has been ongoing to 2010. The first year of the program CRAA transported only 32 wild steelhead (2005). In 2010, CRAA transported 1402 wild steelhead! |
CRAA plans to follow up this study with a new study (2012-2014) to see if any additional divergence has occurred as the hatchery and wild populations have been separated partially. Many wild steelhead still pass the Streetsville dam and spawn below Norval with the hatchery fish lifted through the ladder. However, in most years reproduction is limited in this reach due to poor summer water conditions (high temperatures). Whereas the transferred wild steelhead have spawned in more suitable cold water tributaries and have a much higher reproductive success rate. Please review the following study for more information:
Report on the genetic structure of Credit River steelhead 
Peter A. Addison and Chris C. Wilson 2007
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