Good day, everyone. Sorry to dredge up an old topic, but I was doing some work the last couple of days that related to some topics on this particular question.
First, I read a couple of papers on reproduction by F1 hybrid sunfish. I'll post the references below for those of you who are truly interested, and may have access to a research library.
Laarman, P. W. 1979. Reproduction of F1 hybrid sunfishes in small ponds. The Progressive Fish-Culturist 41:145-147.
Wills, P.S., R.J. Sheehan, and S.K. Allen. 2000. Reduced reproductive capacity in diploid and triploid hybrid sunfish. Transactions of the American Fisheries Society 129:30-40.
The gist of both papers was similar -- that the hybrids have a MUCH reduced reproductive capacity compared to pure bluegills. Incidentally, in the Wills study, the bluegill X green sunfish hybrid exhibited less reproduction than the bluegill X redear hybrid (with both FAR below pure bluegills). Of course, the question always remains: what was the purity of the original parents.
NOW -- I still don't mean to imply that the future generations of F1 hyrids are OK. In both studies, there was reproduction, and Greg Grimes clearly discussed the small size of most of these future generations.
I also read a new study this weekend from Southern Illinois University biologists that substantiated another point made by Greg on this thread (hybrid striped bass vs. largemouth bass). The SIU study compared predation efficiency of largemouth bass and hybrid striped bass that were feeding on bluegills. In tanks with "structure" (in this case, artificial vegetation), the largemouth bass were more than four times more efficient at capturing bluegills than were the hybrid striped bass. In open water, with no structure, efficiency was similar between largemouths and the hybrids.
So, I thought some of you might find these "tidbits" of interest.
Dave
