This was posted a while ago but I thought I would share some info I learned when I stocked my pond last fall with 2-3Lbs rainbows.
I stocked aprox 80 fish and asked the guy where I got them from if there is any chance they would reproduce...he said never and not because there isn't running water or a gravel bed but because all the fish they have are Female.
I thought that was strange so I asked how do you guys get them to breed. Turns out that when they lower the water temps down to a certain temp and change there food in one of the tanks the females that were in that tank start producing sperm.....
I am not at all into this science stuff and sounds pretty freaky to me but I guess it works! Most of the places they sell there fish to are for food and he says by having all femails the mortality rate drops down to almost 0 as they don't fight or get marked up nearly as bad.
The place where I got them from also has Artic Char and he says its the same for them. I asked about possibly getting a few of them and he said no...they are under strict guidelines from the MNR so they can't sell them and they also can't come in contact with any surface water or water that will be come surface water.
Anyone else know anything about this whole self reproducing female rainbow trout thing?
Ryan
Believe it or not a good proportion of rainbow trout on farms these days are sterile females or triploids. Even my DNR has planted some sterile females. Instead of going to expense of keeping broodfish on hand, feeding them and the hassle of manually spawning them in uncomfortable cold temps (for the workers) many farms are ordering eggs from companies like the following:
http://www.troutlodge.com/?pageID=8D8C9607-3048-7B4D-A94D5EA9242EBCB3I believe your questions are answered on the site.
One added benefit of the sterile females is they put the energy they would have put into gonadal development into growth.
