- Written by Don C. Keller, Certified Fisheries Scientist
Americans have always been very adaptive and innovative. If we need something, we build it. We built 4-wheel drive pickups to get us in and out of deer camp, Corvettes to attract the “Honeys,” and M-1 Abram tanks to chase down Iraqis. We bred horses to run the Kentucky Derby and horses that will cut cattle in a stockyard, dogs that will point quail, dogs that will break the ice to retrieve a duck, and dogs that will tear off your leg if you try to steal our lawnmower. Why then, with all the billions of dollars spent on bass fishing, hasn’t someone built or bred a better bass?
For more than three decades many fishery biologists and bass anglers have touted the Florida largemouth bass as the answer to trophy largemouth bass management. As California’s state record largemouth bass began to increase during the late 1960s and 70s (the results of earlier Florida largemouth bass introductions) everyone wanted to jump on the bandwagon. Nearly every state in the southeast outside the native range of the Florida largemouth bass and its intergrades (Florida and South Georgia) watched their state rod and reel record increase as a result of Florida largemouth bass introductions.
During the last 30 plus years there has been considerable research on the Florida largemouth bass, which has produced some consistent and interesting information, recorded in the scientific literature. Here are a few quick facts.
In southern latitudes, Florida largemouth bass live longer and grow faster than northern largemouth bass after age two. Outside of southern latitudes, Florida bass grow slower than native (northern) bass.
Florida largemouth bass are not cold tolerant, rapidly decreasing temperatures can cause mortality. Stocking Florida largemouth bass in northern latitudes can have possible negative impacts on native largemouth bass populations.
Florida bass are significantly more difficult to catch on artificial lures than northern bass. This difference in catchability is measurable at age one and increases, as the fish get older. Catchability is a genetic trait that is passed on from parent to offspring. An aggressive feeding brood bass will produce an easy to catch offspring.
Behavioral differences have been observed between Florida and northern largemouth bass. Floridas appear to be more skittish and in combination with northerns occupy more offshore areas of the lake.
The northern-Florida cross (F-1) is gaining in popularity in the South because of its fast growth rate and aggressive feeding behavior. How are these bass produced and what is a true F-1?
“F-1 or Tiger Bass production has to begin with pure stocks of Florida and northern largemouth bass,” says Don Keller of American Sport Fish Hatchery in Montgomery, Alabama. “We not only keep both strains separate, but we use PIT tags and external fin clips to identify strains and each individual brood fish,” notes Keller.
PIT tags are tiny transmitters that are inserted into the body cavity of the fish through a special hypodermic syringe. The tag does not have a battery, but its signal can be read with a special scanner whose magnetic field causes the tag to transmit a unique16 digit code. This allows the biologists to track data such as strain, sex, age, growth rates, and production from each brood fish. Each strain is then fin clipped by removing either the right or left pelvic fin as an external mark.
“American Sport Fish maintains more than 1,000 pounds of brood largemouth bass,” claims Keller. “We feed these bass approximately eight thousand pounds of live fish each year, primarily goldfish, koi, shad, and tilapia. Our brood bass are in top condition when it is time for spring spawning.”
Brood largemouth bass are removed from the hatchery ponds in early February and separated into males and females of each strain. A select number of these fish are spawned in the early spring in laboratory conditions where the length of daylight and temperature can be controlled. Pairs are placed in spawning vats and eggs are deposited on artificial spawning nests. Eggs are then removed and hatched in shallow troughs. Once the tiny bass fry begin to swim, they are transported to production ponds where they grow to two inches long before they are harvested.
When water in the ponds reaches prime spawning temperature (68 to 70 F), pairs of largemouth bass, usually female Florida largemouth bass and male northern largemouth bass, are placed in clear spawning ponds. Pairs are encouraged to spawn on artificial substrate so that eggs can be removed and hatched in the laboratory. Spawning here begins just as it would in your pond or lake with the male largemouth bass establishing a nesting site. He then entices a female to join him and after considerable courtship behavior, she deposits part of her eggs and he simultaneously fertilizes them. In the first spawning for the female, approximately half of her eggs will be deposited. This female may spawn multiple times; each subsequent spawn will contain fewer eggs.
In natural conditions the male largemouth bass will stay on the nest fanning the eggs and protecting the newly hatched fry. These fry cannot swim or eat, as they have not yet developed fins or mouthparts. They get their nourishment from an attached yolk sac or oil globule. It usually takes four to seven days for them to begin swimming and feeding on tiny insects (zooplankton). The male will remain with the school of largemouth bass fry guarding them from predators until they reach a size of approximately 3/4 inch. Then the fry become fair game for the male and other bass in the pond. The school soon breaks up and the little fingerlings are left to fend for themselves.
After spawning, Keller says that brood fish must be carefully separated by strain. “Producing F-1s is a lot more involved than just spawning a single strain or producing bass from a mixed genetic brood stock. We go to great lengths to insure the genetic integrity of our stocks. Our Florida strain largemouth bass brooders are from proven trophy lines and our northern largemouth bass have been selected for 15 generations for their aggressive feeding behavior. We produce a true F-1 and because of brood selection, a unique F-1 that we have trademarked TIGER BASS,” says Keller. “There are some hatcheries that claim to produce F-1s, but what they really have is an unknown mixture of Florida and Northern genetics, the Heinz 57 of bass,” exclaims Keller.
Now the next time you hear some one talking about F-1 or Tiger Bass, you will have a little better understanding about what they are and how they were “built.”
Barry W. Smith is a certified fisheries scientist.
- Written by Barry W. Smith, Certified Fisheries Scientist
Harvest is one of the most important techniques that can be used in the management of bass in private lakes and ponds. Many lake and pond owners often misunderstand the concept of harvest. Although lake management publications will often recommend removing 15 to 30 pounds of bass per surface acre, depending on the fertility of the lake, removing four 5-pound bass does not have the same effect as removing 25 bass that average .8 pounds each. The key to the success of bass harvest is understanding which sizes of bass need to be removed, and why. This is what many management biologists call “selective” bass harvest.
Within the southeastern United States, most bass become sexually mature at 1 year of age and a total length of approximately 8 inches. Largemouth bass typically begin spawning as early as March and spawn through June, although the peak of the spawn may occur during April. In most lakes or ponds where there is not an excessive population of golden shiners, 3- to 5-inch bluegill or extreme turbidity (muddy water), bass will successfully produce many more fingerlings than are necessary for replacement of those adults that are caught and those that die of natural mortality. As a pond ages, there may be two to five or more age classes of bass that can spawn each spring. Hence the basis of the biggest problem of managing bass in private waters…overpopulation of small bass.
Overpopulation of Largemouth Bass
More than 85 percent of lakes and ponds that are checked by private and state fisheries biologists are crowded with small bass. This is caused by two primary factors, successful annual bass reproduction and survival, and the lack of adequate bass harvest.
Why is this a problem, won’t these small bass eventually grow into big ones? The answer to that question is No! The reason is that the more small bass that you have the less food that each one has to eat and the slower their growth. Bass that are 12 inches long are not “yearlings” but may actually be 2 or 3 years of age, or even older. How do we know this, you may ask? There have been many research studies that have actually aged these bass through studying the age marks in scales and in the ear bones, called otoliths. These techniques show not only how old a bass is, but also its rate of growth since birth.
As a new pond or lake begins to age, especially beyond year three, food of the size necessary to grow larger bass typically begins to disappear. Although there may appear to be a lot of food in the form of small bluegill, this is not the size forage that grows big bass. The forage fish (primarily bluegill) are continuing to reproduce; however, most of the small bluegill are consumed by the myriad of small bass before they reach a size that larger bass need for growth. Although larger bass often have to eat small bluegill or other forage, the energy they gain by catching a small bite is not enough to make them grow.
Selective Largemouth Bass Harvest
It should be obvious by now that if small largemouth bass are a problem in retarding the growth of larger bass, then we need to make a concerted effort to remove small bass. We should select for the size and number of largemouth bass that need to be removed.
How do we determine what our selective bass harvest should be? The best method is to conduct an electrofishing balance check of the fish population, to determine the relative numbers and sizes of food fish and the numbers and sizes of largemouth bass in the population. In addition, fisheries professionals can determine the relative weight or condition factor of each bass in the sample, noting whether it is above or below average in its weight. This gives both you and the fisheries biologist a base line of data to determine which sizes of bass are most numerous and which sizes are thin, or without adequate food. We can now decide, based upon actual data, which bass should be selected for harvest.
Now the work begins! Not only do you have to be aware of the new selective bass harvest, but also you must convince your fishing companions of the importance of harvesting fish in this selected size group. You can no longer accept the standard response to your fishing questions, such as: “Al and I had a great day. We caught about 40 bass but we didn’t keep any of them. You know we just didn’t have time to clean them and besides, we forgot our cooler and our filet knife. You know that Francis and the kids don’t really like to eat bass, especially since that time I burned the grease in the kitchen. We almost never got that smell out of the house.”
It is difficult to manage a lake for quality largemouth bass fishing with friends like that. You can make rules, however, that if they don’t help with the selective harvest, they do not get to fish. Those of you who recognize the importance of selective bass harvest and obtaining annual harvest goals will be rewarded by outstanding bass populations and fishing opportunities. In typical situations, the majority of bass fishing occurs during the spring. This is a wonderful opportunity to employ an advanced selective harvest technique that will result in even better fishing for larger bass.
Advanced Techniques for Selective Largemouth Bass Harvest
It is true that the majority of largemouth bass weighing more than 3 pounds are females and that 99 percent of bass larger than 5 pounds are females. If you want to increase the percentage of large bass in your lake, you should attempt to increase the percentage of females in the population. How do you accomplish that? Remove as many males as possible while you are fishing. Remember that most of the fishing effort and catching occurs during the spring, when it is relatively easy to distinguish males from females.
During the spring, male bass are more vulnerable to angling as they are the first ones on the shoreline, looking for nesting sites and then building nests. Males become much easier to catch during the spawning season, as they are aggressively defending their nests and guarding the schools of newly hatched fry. During the pre- and post-spawn, males and females are more accurately identified by physical characteristics.
Physical Characteristics of Male and Female Largemouth Bass During the Spring Season
Females will typically have a swollen or fat belly before they spawn, but in lakes where food is plentiful, so will males. Although this is the first observation we make, it is not an accurate method of determining sex. Look more closely at the scaleless area around the vent, which is located at the posterior portion of the belly. This area is aptly called the urogential opening, because there is a vent or opening for excretion of wastes and an opening for extrusion of sex products. This scaleless area around these vents is shaped differently for males and females.
Hold a bass you catch during the spring on its back, belly skyward. Look carefully at the area around the vent that has no scales. The area will be almost perfectly round for males and oblong or pear shaped for females. 
Examine several bass and closely observe the opening toward the tail, this is where eggs are extruded by the females, and milt by the males. Is this opening reddened or swollen? If so, it is very likely a female. This swollen area on females is called the genital papillae, and it will remain red and distended prior to spawning and for many weeks after spawning. Bass do not deposit all of their eggs during their first spawning attempt and will remain ready to spawn again for a month or more after their first spawn.
Males do not have a genital papillae and their vent is seldom red and almost never swollen. Males will often exude a small amount of milt if pressure is applied with the thumb from the top of the belly toward the vent. Look very carefully and you can often see a tiny amount of white liquid accumulate around the vent. This will often start pre-spawn and last until the spawning season is through.
Study the photos in this article and you will be able to sex bass well enough to influence the percentage of females in your lake. If you are going to selectively harvest bass during the spring, you can positively influence the population of your lake by harvesting as many males as possible. You will not harvest too many males. Do not fret over harvesting an occasional female, harvest as many males as you can!! This technique will work for you only in the spring. It is possible to change the sex ratio of your bass population from 50% females to 85% females by harvesting males.
Barry W. Smith is a Certified Fisheries Scientist.
- Written by Don C. Keller, Certified Fisheries Scientist
Many existing lakes and ponds that contain both bass and bluegill may benefit significantly from a few basic and cost effective management techniques. A little knowledge coupled with some common sense will turn your lake into a great place to fish. One of the most important and economical management techniques that can improve the fishing in your lake is pond fertilization. I will explain why this is important, what types of fertilizer to use and how pond fertilizer works to improve your fishing.
Pond Fertilization
Applying proper pond fertilizer to a lake has the same effect as fertilizing your garden, your lawn or agricultural crops, it increases your production. In fact, research in ponds has proven that pounds of fish produced may be increased 300 percent or more by proper fertilization. Clear, infertile ponds and lakes may have a total carrying capacity (total pounds of all species and sizes of fish) of less than 50 pounds per acre. Well-fertilized lakes may produce 250 pounds or more of total fish per acre, providing many more opportunities for catching quality-size fish.
How does this happen? Pond fertilizer increases the small, green, single-cell plants called phytoplankton (this is what makes your pond have a green tint). Tiny insects called zooplankton eat phytoplankton. These little insects are eaten by larger insects, which are then eaten by bluegill. The bluegill are eaten by bass and BAM! You have a great fishing hole.
The more food you produce from fertilization, the more fish you can grow. It is a simple and cost effective way to boost the growth and the numbers of bluegill and bass in a lake. As with fertilizing your garden or an agricultural crop, soil pH can play an important part in determining how effective the fertilization program works. In many soil types throughout the southeast, agricultural limestone should be applied to lakes to neutralize acidic pond bottoms and make the fertilizer produce more food. Have the total alkalinity of your water tested to see if your lake requires liming.
Types of Fertilizers
There are several types of pond fertilizers. Granular fertilizers were developed for ponds during the early 1950s and the standard 40-pound bag of 20-20-5 (N-P-K) is still used by many pond owners. Granular fertilizer should never be broadcast or poured from a boat because the phosphorus can become chemically bound by the bottom mud and will not dissolve. Granular fertilizer should be placed on a platform that is about 18 inches below the pond surface. It would take 200 pounds of granular fertilizer for a five-acre pond.
Liquid fertilizers, such as the green 10-34-0, have been used with good success. This fertilizer is much heavier than water (13 pounds per gallon) and must be mixed with water before being applied to the pond, otherwise it will layer on the bottom. Although effective, it is very messy and usually requires mixing one gallon of fertilizer to four gallons of water. Once mixed, it can be poured from a boat or broadcast from the bank. A five-acre pond would require five gallons of liquid fertilizer (65 pounds) plus 20 gallons of water (160 pounds) that means you would have to handle 225 pounds of material.
There is a new type of concentrated, totally dissolvable powder or crystalline fertilizer that requires no mixing, no platforms and only recommends five pounds per acre to apply. Pond fertilization could not be easier. Formulations vary from 10-52-4 to 12-48-8 and one of them, Biologic’s Perfect Pond Plus (12-48-8) contains a micronutrient package that is beneficial to many crops. This fertilizer, which has the consistency of powdered sugar, can be broadcast from the bank or a pier or may be poured from the side of a boat. A five-acre pond requires only 25 pounds as compared to 200 pounds of granular or 65 pounds of liquid, plus 20 gallons of water (160 pounds).
With the new powdered fertilizer, a five-acre pond could be fertilized from a single location if applied with a breeze at your back. This fertilizer dissolves in the upper two feet of the pond and can be distributed throughout the pond by wind currents. Most ponds require applications during March through October. Fertilize when the water visibility is greater than 18 to 24 inches. Do not fertilize if the water visibility is less than 18 inches, the pond may develop a heavy and potentially dangerous plankton bloom.
Aquatic Weeds
Do not fertilize your lake or pond if there is significant population of aquatic weeds or algae. Why is it important to control these plants? Because they can reduce the nutrients used for producing phytoplankton (the basis of the food chain for your fish) and they increase your risks of an oxygen related fish kill. A clear, weedy or slime-infested pond is not productive, is difficult to fish, and cannot be properly fertilized. Fertilizing aquatic weeds or algae makes them grow more rapidly. Weeds have to be controlled before an effective pond fertilization program can be initiated.
Fishing
Fishing can be enjoyable for the entire family, especially in well-fertilized ponds. Even small ponds of an acre or two can produce plenty of harvestable fish for your family and friends.
Don’t be afraid to keep bluegill and bass to eat. Harvest is an important part of any management plan. In most fertilized ponds and lakes, bass harvest should be 15 to 25 pounds per acre per year. More than 75 percent of lakes today have too many small bass because there has been inadequate harvest. Bass harvest should be selective, remove the size bass that is the most abundant. For the average lake in the southeast, bass 14 inches and under should be harvested.
Bluegill should also be harvested; however the old adage that you can’t catch too many bluegill is not true. Allow you and your friends to take the bluegill you want to eat, but do not harvest more than 50 pounds per acre if you want to continue to catch big bluegill.
Managing your lake is not complicated or expensive. Put a little effort toward improving your lake and utilize that wonderful resource you have on your property. For specialty fisheries, such as trophy bass or trophy bluegill, consult a professional fisheries biologist.