now that the Hybrid blue gill are spawning and the trout are not feeding we have an over abundance of the blue gill with no predation going on. Soon we will have what we did not want a stunted pond of bluegill. The hybrids have been a real disappointment. considering putting a couple of northern pike in or some other predator fish, but if the waters are too warm for the trout prob. the same situation with any other predator fish. The pond would be difficult to seine, lots of large stones on the bottom. Maybe large mouth bass would help, they like warmer waters.
I'm curious Nils, were you lead to believe that HBG were sterile, and would not reproduce? They are sometimes touted as such, when in fact they are quite capable of reproducing. The benefit of HBG, as far as I'm concerned, is that most of the first generation, (F1's), are male. Some studies suggest 90-95% male, in fact.
Esshup is right, if you want to lessen the odds of a stunted pond, then I would fish out the HBG, and make sure to keep any underwater vegetation to a minimum. I have found these fish to be quite predatory in nature, and have observed them feeding on yoy many times. However - it has been my experience that they will not succesfully control their own reproduction to the extent that LMB, or another predator species, will. I do not consider them self-limiting.
The fact that you stocked the HBG two years ago, coupled with your northern location, means that any LMB stocked now will probably have their work cut out for them. Your saving grace might be the fact that we're talking HBG, not native BG. I think it might be too late if they were regular BG. I'm no authority on NP, but it seems to me that they would enjoy the fusiform shape of your trout, possibly preferring them over the HBG?
I think if it were me, I would concentrate on fishing the hybrids out, and stock some LMB in the 6-9" range. I would be afraid that any larger Bass might also decimate the rainbows you stocked this year.
