Florida bass are different creatures

Decision on Gulf amberjack shows federal management on brink of breakdown

Largemouth bass are the most popular freshwater recreational fish in America, in spite of the changing face of the fishery. Gone are the days of a bass fisherman being pictured as a grandfather in a rowboat with a grandson or contemplative pipe-puffing angler patiently casting a clunky wooden topwater plug with his old knuckle-buster.

Now, largemouth bass are a competition fish, and a picture of the average angler would reveal sun-bronzed athlete wearing a fishing shirt plastered with patches from supporting equipment manufacturers.

The changes in the fishery have also resulted in an increased demand for management for bigger largemouth bass.

One approach to producing large bass from a waterbody has been to stock it with Florida largemouths. These fish, technically called Micropterus salmoides floridanus, are a different subspecies from the northern largemouth bass, Micropterus salmoides salmoides, found in Louisiana.

Florida largemouth bass (FLMB) are native to Florida and southern Georgia, where they evolved in response to local conditions. The northern largemouth bass (NLMB) is found in the rest of the species’ native range in North America.

The single characteristic of FLMB that makes them so attractive to anglers is the fact that they grow larger than NLMB. But FLMB are different from their NLMB brethren in other ways as well, particularly in behavior.

A study done in Lake Tawakoni, a 37,000-acre reservoir in Texas, illustrates some of those differences. For the study, 12 NLMB and 12 FLMB were obtained from a state hatchery and tagged with ultrasonic tags. Hatchery fish were used to make sure that pure-strain fish were being tested, not hybrids, like may be found in the wild.

They were all released in the same area of the lake at the same time. Their movements were then checked with a radio receiver every two weeks for an entire year. Some interesting results were obtained.

“NLMB had bigger home ranges than FLMB,” researchers reported. “On average, NLMB spent 75 percent of their time within a 54-acre area and 95 percent of their time within a 165-acre area. FLMB spent 75 percent of their time within a 48-acre area and 95 percent of their time within a 110-acre area.

“Both subspecies heavily used shallow water. FLMB spent 83 percent of their time and NLMB spent 95 percent of their time in water shallower than 7 feet, even though water 40 feet deep was close by. The deepest water that NLMB moved to was 18½ feet. The deepest water for a FLMB was 22 feet. FLMB definitely preferred somewhat deeper water than NLMB though.

“FLMB showed a distinct movement pattern toward shallower water as surface water temperatures increased. No such pattern was seen for NLMB.

“FLMB were located significantly farther from shore than NLMB. FLMB averaged 44 yards (maximum 226 yards) and NLMB averaged 10 yards (maximum 101 yards) from shore.”

Aquatic vegetation was, by far, the most heavily used habitat by both subspecies. The accompanying table shows the habitat preferences of each subspecies.

Simply stocking a water body with FLMB does not guarantee more large bass. Certainly, the genetics of the subspecies favors larger size. Some fast-growing FLMB in their native range can reach 10 pounds in four years. But that is exceptional.

Like any other fish, FLMB need to live a long time, typically 9 or 10 years, before they can grow to large sizes. Protective regulations are often necessary to keep human harvests low enough for the fish to live long enough to grow large. And, in some water bodies, natural mortality (deaths) are high enough that few or no FLMB or NLMB will live long enough to grow large, even with protective regulations.

Research also strongly indicates that FLMB will grow faster in water bodies in which NLMB grow faster, so the choice of waterbody in which to stock the fish is very important.

Also, it is unreasonable to expect FLMB to do as well in most of the NLMB range as they do in the home range they evolved to live in. Even in Florida, differences exist. For example, it takes two years longer for a FLMB to grow to a true trophy size of 10 pounds in northern Florida than it does in southern Florida.

A final note about what can be expected from FLMB stocking is in order. In all waterbodies that hold a native population of NLMB, it takes multiple massive stockings of FLMB to have a significant impact on the bass population. A million tiny FLMB sounds like a lot of fish to put in a lake.

But the native NLMB reproduction, even in a lake with a poor bass population, may be a hundred or more times that.

In comparison, the FLMB stocking is tiny and their numbers are overwhelmed by the numbers of NLMB spawned in the lake. And to make things more challenging, on a one-for-one basis, NLMB will almost always out-compete FLMB, simply because they are evolved for the area they are in, and FLMB are out of their element there.

Changing the genetic make-up of a bass population in a waterbody requires a long-term stocking commitment with a large number of fish.

About Jerald Horst 959 Articles
Jerald Horst is a retired Louisiana State University professor of fisheries. He is an active writer, book author and outdoorsman.