Growing Largemouth Bass In the South vs. North

AS SEEN PUBLISHED IN POND BOSS MAGAZINE

For decades, people in the great state of Texas have been managing private water to produce double digit Largemouth Bass. Over the past 30 years, this trend has spread across the country and has become somewhat mainstream among affluent landowners and outdoorsmen. As the industry continues to mature, trends continue to emerge. This has helped biologists better understand why bass grow larger in some areas and not others.

Largemouth Bass grow bigger in the south. This makes sense, since the Florida strain of Largemouth Bass have the ability to reach larger sizes, and they only live in the southern regions since cold water is lethal to them. As biologists work to push bass growth, they find themselves asking the question: is advantage due to bass genetics, or are other variables fueling this advantage?

So, what advantage does the south have? The answer is simple – warmer water temperature. It turns out that water temperature is the most critical variable that impacts Trophy Largemouth Bass fisheries. Temperature is the primary driver that influences the home range of the superior Florida Largemouth Bass strain. Equally as important, water temperature influences the production of phytoplankton, which leads to the production of forage fish. Simply put, phytoplankton, zooplankton, invertebrates, forage fish, and Largemouth Bass all rely on optimal temperatures to thrive. 

For the purposes of this article, the area of the United States where Florida strain Largemouth Bass are able to survive year-round will be referred to as the “Southern Region”.

As indicated above, this Southern Region has far more plankton growing days, which is the rocket fuel that propels the forage fish population further than waterbodies north of them. This extended growing season means more opportunities for forage fish to reproduce, as well as reach larger sizes within a growing season. This all leads to growing more pounds of forage fish using plankton compared to water to the north.

On the other hand, maintaining proper sized forage can be a big challenge for areas to the north.  Some of these cooler climates have the ability to stock threadfin shad; these shad get off to a later start, resulting in less generations of shad present in a growing season. Rather than reaching large sizes, these shad typically die off due to water temperatures dropping down to lethal levels. As a result, these waterbodies struggle to maintain decent size forage fish. This puts more pressure on other forage species such as Bluegill, which struggle to reach greater than 2.5-3 inches within their first growing season. This all leads to a higher probability of a smaller  forage than what is desired by the bass population.

Stocking F1 Largemouth Bass is one solution that was introduced many years ago to address the inferior bass genetic issue. These F1 bass are created by breeding Florida and Northern strain Largemouth Bass with each other, resulting in offspring that can tolerate colder water temperatures than their Florida strain parent, while reaching larger top-end sizes than their northern strain parent. As with the Florida strain, these F1’s have a lethal cold temperature limit, which restricts how far north they can survive in the winter. Although somewhat subjective, F1s typically do not survive in areas of the country where lakes and ponds ice over regularly each winter.

One downside to the improved genetics that F1s provide, is that the offspring produced by two F1 bass are genetically inferior to their F1 parents. As a result, Trophy fisheries who have F1s present should take additional management steps to offset this challenge. If you live up north where F1s cannot survive, keep in mind that northern strain bass will often top out 30-50 percent smaller than the Florida strain bass if managed properly. F1s, on the other hand, can get much closer to the size of Florida strain bass, although at the end of the day they are inferior.

If northern waters are hoping to grow close to the same biomass of forage fish within a calendar year, they will need to produce this biomass within a shorter period of time as a result of the shorter growing season. The only realistic method available to grow forage faster than with plankton is to supplement with pelleted fish feed. As a result, these waterbodies must feed their forage fish aggressively throughout the entire growing season. When executed properly, this will help tremendously to overcome the productivity headwinds. 

As productivity is increased, it is important to understand that proactive water quality management is needed to prevent fish stress as well as a fish kill. Some key parameters to pay attention to are dissolved oxygen, pH, alkalinity, total phosphorus, and total nitrogen. In many cases, it can be an expensive endeavor to monitor and  keep these parameters within their desired ranges, but if done successfully, the food-chain will have a significantly better chance of thriving. 

When looking at water quality by region throughout the country, the Southern Region has a challenge. Surface water temperatures become hot in the summer. This hot water is good for forage production, but is not as good for growing Largemouth Bass. Unfortunately this issue is not something that can be solved very easily. The best solution to this temperature challenge is to have a decent amount of water between 12 and 20 feet deep, as this deep water provides cooler water temperatures for bass. Maintaining sufficient dissolved oxygen up towards the surface as well as down in this deeper, cooler water is a challenge that would need to be overcome. As a generalization, this Southern Region can struggle to maintain sufficient oxygen levels due to the hot summertime water temperatures.