All:

I seem to have stirred up a hornet's nest with this one. As I tried to explain during the talk, this is not a major concern in pond management because genetics are secondary to food, age, and water temperature. However, outbreeding depression is clearly demonstrated in other agriculture. Farmers raise F1 hybrid corn, but they never save the seeds for replanting. Why? Because the subsequent generation does not perform as well. Now bass are not corn, and Florida bass and northern bass are much more similar than the parents of many hybrid species. In reality, we probably will never empiracally test it, since it would take 10 to 20 years to trully demonstrate, and there are too many confounding factors to sort out. I would be more worried about inbreeding depression - that is small gene pool - than outbreeding depression. However, if you would like some follow up reading, I list a few studies that you can check out below. You'll notice similar names on all of the papers because they are the primary researchers working with bass genetics. One study that addressed the potential for outbreeding depression is:

Philipp, D. P., J. E. Claussen, T. W. Kassler, and J. M. Epifanio. 2002. Mixing stocks of largemouth bass reduces fitness through outbreeding depression. Pages 349-363 in D. P. Philipp and M. S. Ridgeway, editors. Black bass: ecology, conservation, and management. American Fisheries Society, Symposium 31, Bethesda, Maryland.

This study did not directly test the outbreeding depression of F1 hybrids but instead it looked at the effect of stocking one genetic stock on the other. However, the mechanism is the same.

Dave Philipp had several earlier papers that addressed the potential for later generation intergrades to have reduced performance:

Philipp, D. P. 1991. Genetic implications of introducing Florida largemouth bass. Canadian Journal of Fisheries and Aquatic Sciences 48 (Supplement 1):58-65.

Philipp, D. P. 1992. Stocking Florida largemouth bass outside its native range. Transactions of the American Fisheries Society 121:688-691.

Philipp, D. P., and G. S. Whitt. 1991. Survival and growth of northern, Florida, and reciprocal F1 hybrid largemouth bass in Central Illinois. Transactions of the American Fisheries Society 120:58-64.

Another paper that I recommend is:

Kassler, T. W., J. B. Koppelman, T. J. Near, et al. 2002. Molecular and morphological analyses of the black basses: implications for taxonomy and conservation. Pages 291-322 in D. P. Philipp and M. S. Ridgeway, editors. Black bass: ecology, conservation, and management. American Fisheries Society, Symposium 31, Bethesda, Maryland.

In this manuscript, the authors offer substantial evidence that suggests "Florida bass" and "largemouth bass" are two separate species.

Think about it, stew over it, but I hope you talk nicely about me in the end \:\)