Here is an extended answer to your simple question.
Kentucky asks -
If these weights are the upper end of northern bass, what do you think the low end of a Florida bass is (in a middle of the country state like Kentucky)?
This is a very good question. My final answer is at the end of this verbose post. To verify we are discussing the Low End for length and weight of an ALL female FL bass population before they die. Qualifier - I am not real familiar with environmental stockings of FLMB nor F1 LMB.
My answer is - It All Depends on several if not numerous important points for growing trophy size LMB.
1. Main Factor is what percent of the stocker FLMB will survive central Kentucky's future winter conditions. They have to survive the winter cold conditions and not get overly stressed. My main concern is taking lots of effort and time to get the FLMB growing to 5, 6, 7, or 8 lbs and then have a harsh winter occur at the pond and have a significant percentage of the all females die. Very Risky Business IMO especially when other big bass options are available. But none the less, a big learning curve will be obtained
Winter is always the hardest time for fish to survive. Some winter mortality of FLMB will IMO definitely occur in central KY; how much is the big question????. Weather extremes seem to be more commonplace. The F1 genetic combination of stocker bass (northern LMBXFLMB) IMO would provide better overall results long term and still make it more feasible to grow a 10 lb bass. Finding all female F1 LMB would be the initial biggest hurdle for your all female bass project. PLUS – I think if you use FLMB or F1 females,,,, be prepared to supplemental or periodically stock akd ladder stocking some females due to attrition from several forms of mortality that will occur during the all female big bass growing project. Total bass mortality could be 10 to 15% per year. Angling of bass is a big stress producer especially as they age older.
Know that not all dead fish float.
2.. What factors will influence FLMB for years of growth toward the 10lb size in KY? One point in favor of FLMB in KY is they ‘could’ repeat ‘could’ live longer than the comparable FLMB living in the most southern states. Living longer could allow the bass to be alive longer while adding to its final body weight compared to a shorter life span of Southern growing FLMB. This is an energetics thing where the rate of growth tends to shorten life span. Slower growing organisms tend to live longer than those experiencing fast growth. DO WE KNOW GOOD INFORMATION FOR THE AVERAGE OR “NORMAL” LIFE SPAN OF NORTHERN VERSUS FLMB??
3. The FLMB ability to survive a future severe winter cold spell in your region of Kentucky. IMO older the bass becomes the more vulnerable it is to temperature extremes. Some will live, and some will not survive due to natural genetic variation of temperature tolerance of the FLMB species genetics. Each specie with DNA has numerous aspects of some natural genetic variability. Natural genetic variation exists in all life forms even the COVID virus.
4. Since FLMB will have southern LMB genetics will they not be as hungry or not eat as much when the pond water temperatures drop below 60F. I use 60F versus 50F because the FLMB are naturally adapted or evolved to southern winter water temps and not the common 50F temp that is often used for fish feeding and growth. Do you know how many days your water temperature is 60F or below?? Bass not eating means not growing and probably beginning the loss of some weight that needs to be regained before growth can again occur when the temperature again gets above 60F. In water colder than 60F for FL bass their metabolism slows down more than a northern LMB who tolerate and feed okay when water is 50F. Below 50F FLMB would be more lethargic and likely not eat compared to the northern LMB winter feeding behavior. My angling experiences and fish feeding sessions prove this fact. When FLMB and all fish are temperature stressed this is not healthy for their well being. IMO that is why many FLMB die during winter conditions; due to impacts of winter low temperature stressors.
However,,, on the other end of the water temperature spectrum story, the FLMB in KY will not have the reduced feeding periods during the high water temperatures above 90F that are common in the Southern states. Water temps above 90F are said to cause LMB to be lethargic and reduce the food intake of LMB and probably also the FLMB.
5. Good habitat is not for anglers catching LMB but for good diversity and proper amount of habitat is needed for it’s ability for growing more forages to feed the FLMB for optimum growth rate/s. This is important for getting the bass to the big or trophy size before they die of stressors of old age.
6. Forage diversity is important. The numbers of good types forage foods to grow big bass vary with the season. Diverse types of forage species produce proper amounts of the best sizes of food/s each season of the year. Optimum feeding sessions during each season allows LMB to get the best and most efficient weight gain for the least amount of energy expended for number of organisms eaten. Optimal Foraging Theory. The bigger a LMB gets larger easy catch food items should be commonly available to produce the best most efficient bass growth. Vulnerability of the forage food/s to be captured and eaten is an influence on how well the bass can catch food and then grow optimally. It usually takes several strikes for a bass to capture its food. Each travel session and strike attempt expends or consumes energy and reduces its growth potential.
7. Food quality . Research has shown that the different species of food items or species eaten by LMB have different protein and fat contents. Both amount of protein and fat are very important for best growth of bass. High quality foods. Note that you might likely have to supplimentally stock some high food value trout each fall to help the bass better endure the winter conditions. Trout stocking in CA are responsible for growing the biggest California LMB.
8. Food availability. Proper sizes and numbers of good items need to be continually abundant so LMB have short time periods without food in the belly. Best growing bass have full bellies EACH DAY. Dave Davidson says a bass should be able to while it is asleep awake with a full belly. This means LOTS of PROPER forage foods ALWAYS available.
9. Last but definately NOT least is annual water quality conditions. This is very important for several reasons. 1. Good dissolved oxygen throughout the entire water column reduces stress for the bass. Stress reduces growth. 2. Good water chemistries supporting proper plankton blooms 3. . Plankton blooms should have minimal percentages of Cyanobacteria aka bluegreen algae that contain low quality food value comprising the basis of the food chain. Bluegreen ‘algae’ blooms have overall low food value for the entire pond food web. As goes the phytoplankton community composition this controls the quality of the food available for the entire upper food chain or food web. Having good phytoplankton species blooming during summer ALWAYS produces the best fisheries.
Having said all this,,, if stocking ONLY female FLMB and you are lucky for mild winter weather conditions and some survive 9 to 11 years, I think the “low end” of the weight of those LowEnd bass in the all female FLMB population should be around 7 - 8 pounds before they die. This is because I have learned from my experiences with all female fish populations that not all females have the same growth potential, just as not all male humans do not grow to be 7ft tall despite all being the same specie or are even as brothers from the same parents. Natural variability of all species.
