Building a Better Largemouth Bass
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.