So which is more important for maximizing growth rates of largemouth bass: genes, food supply, or population density? It is an interesting question which gets touched upon at times in various message board discussions. We now have an interesting first glance at a potential answer, and genetics might play 2nd fiddle in some cases. Latitudinal Influence on First Year Growth and Survival of Largemouth Bass by Slaughter IV, et. al. studied first year growth rates of both northern strain LMB (native and non-native populations) and Florida strain bass under similar conditions. The common belief being that fish in the south grow faster, frequently attributed to genetics; “live fast, die young” being one theme along with the frequent stocking of Florida strains to intentionally introduce those genes into the local bass population.
In this paper the authors found that, “the genetic composition of these fish may not always be as important a factor in first-year body size and consumptive demand as population survival and prey availability, both of which are influenced by the host system. Without an adequate prey base to support fast growth and ecological mechanisms to lessen competition or density-dependent growth, it is likely that there would be little increase in the body size of largemouth bass.”
In short, when a particular bass group had the fastest growth rate during its first year as compared to the other two (and it varied between years as to which group grew fastest), it was more likely a result of density dependence and/or prey availability. The less individuals around to compete for exisitng prey, the more food there was to go around per individual bass. Additionally, the greater the prey density of correct size available to forage upon, the more likely to see faster growth. Genetic background seemed to play a less important role in these cases. So good genetics might be important in some instances, but it’s not the “be all and end all” to a fast start on life.