Fish factories

There are five main ingredients that contribute to a successful fish producer

Anglers often ask the question, “Why does one lake produce better largemouth bass than another?”

In many cases, lakes on the same river systems may provide totally different angling experiences. For example, look at two well-known lakes on the White River – Table Rock and Bull Shoals. Table Rock is currently a quality fishery for all three major black-bass species. Bull Shoals, very similar in appearance and size and immediately downstream from Table Rock, also contains all three black-bass species, but quality and quantity are usually not as good.

Even biologists sometimes disagree on the most crucial aspects of a trophy fishery. For the most part, biologists tend to agree on five factors that are common to most largemouth fisheries that regularly produce trophy fish.

“It’s all a matter of habitat,” said Tim Churchill, professional fisheries biologist with the Tennessee Wildlife Resources Agency. He defines habitat as a composite of water fertility, ideal spawning locations, forage quantity, population density and lake structure (especially concerning varied water depths).

Water fertility

According to Kevin Yokum, West Virginia Division of Wildlife fisheries biologist, an unseen aspect that factors into most trophy-bass fisheries – especially largemouth fisheries – is water fertility. Water fertility, though somewhat complicated, can be broken down into a fairly simple equation.

First, the lake or river needs to contain hefty amounts of nutrients, such as phosphorous and nitrogen. There is, however, a limit to the amount of nutrients a body of water can safely contain. These nutrients help produce large populations of microorganisms (plants and animals) crucial for large forage-fish populations. Nutrients also tend to support more aquatic grass and weed growth.

Nutrient levels are not the only aspect of water fertility. For many plants to be able to use the nutrients in the water, the water pH (acid level) must be neutral or close to neutral. In simple terms, the less acid in the water, the more nutrients plants can absorb. Obviously, the more nutrients plants can absorb, the healthier they will be.

So the combination of nutrients and water pH may be the most important factor in developing a trophy-largemouth fishery. Water fertility directly influences the foundation of the food chain, which then affects bass.

Forage quality

Forage varies widely from venue to venue, but bass are predators. As such, they eat what is available to them. In some waters that may be crayfish, hellgrammites, insects and minnows. In other waters it may be threadfin shad, gizzard shad or alewives. And in still others it may be trout, most notably in California, or tilapia in the waters of Mexico.

When it comes to forage, regardless of the type, one thing is for certain – there will be a lot of it if the bass are big. This holds true for the trophy-largemouth waters of Lake Castaic in California all the way to the quality bigmouth waters of New York.

Adam Hater, a professional biologist with Jones Fish Hatcheries (jonesfish.com), points out that a wide variety of forage is a must for a trophy fishery to survive and remain viable over several years or even decades. Hater reminds anglers that not every year’s spawn will be successful for every species of forage. Therefore, a wide variety of forage coupled with high-quality spawning sites for each species is a must for trophy-fish production.

Spawning locations

According to Churchill, largemouths need vast areas of shallow water with very stable water levels to successfully spawn. They frequently spawn in water less than 2 feet deep.

Largemouth spawning grounds generally consist of substrate mixtures of sand, gravel and mud. In most cases, there will be some weed growth in the area and perhaps a stump, laydown or some form of man-made cover to provide protection for their nest and fry.

It is essential that such areas have stable water conditions during the spring spawning season. Water levels that rise and fall destroy the spawn and make natural reproduction nearly impossible. Although stocking programs have, upon occasion, been successful, they are generally not an option unless combined with high-quality natural reproduction. Stocking is too expensive and time-consuming to be viable over a long period of time.

Hater has been designing, stocking and developing trophy-largemouth waters for many years. He agrees that ideal spawning locations must be available for bass, but he also emphasizes that for any water to produce trophy bass it must have suitable spawning areas for the forage, whatever it is. “The forage must be able to reproduce and replenish itself for a bass fishery to be successful,” Hater said.

Population density

Hater also believes that population density affects competition for food. As such it is his opinion that most waters benefit from removal of small bass. While this may not be the best strategy for numbers of fish, it is the best strategy for developing trophies in many fisheries. According to Hater, there may be fewer bass, but they will be much bigger.

The thought of harvesting a bass is offensive to many anglers. The fact is, however, under some circumstances it is beneficial and even necessary.

Water depth

Beyond fertile water, first-class spawning areas and a quality forage base, trophy-largemouth fisheries tend to be characterized by vast areas of warm, shallow water. In nearly all cases they are weedy and filled with stumps, laydowns and other forms of wood structure and cover. There are exceptions, of course. Largemouths can and do survive under a wide variety of conditions. They are, however, by nature a warm-weather, shallow-water fish. They do best under those conditions.

Many top largemouth waters offer at least some deep water. It affords protection from harsh environmental conditions, protection from predators and access to deep-water forage.

For either Florida bass or northern-strain largemouths, long growing seasons (warmer climates), while certainly a factor, may not play quite as important a role as once thought. The five previously mentioned fishery characteristics tend to determine a fishery’s trophy potential before growing season is taken into account.

Consider the thoughts and opinions from these professional biologists when you analyze your local fishing hole for trophy potential. Does it have what it takes?

The roles of management and angler responsibility

Management and angler responsibility play different but equally important roles in creating and preserving a trophy fishery.

Dale Hollow may provide an example of both. It is no secret that some 10 years ago the smallmouth fishing at Dale Hollow could best be described as mediocre. The fish were small – generally weighing less than 3 pounds – and there really were not very many of them.

The Tennessee Wildlife Resources Agency decided to do something about that. They instituted a slot limit on the lake. At the onset it was controversial – very controversial. Many of the dock and marina operators opposed it, as did nearly all the guides. They believed a slot limit would not help the fishing and would drive recreational anglers away from the lake.

How wrong they were! Anglers can now keep one fish under 16 inches and one fish over 21 inches. The fishing has exploded. Four-pound smallmouths are ordinary, and 5-pound smallmouths are common.

At the same time, the angling culture has changed on this Obey River impoundment. Guides just do not allow clients to keep fish anymore – even those well over the legal limit. Most carry cameras in their boat and encourage photos along with fiberglass replicas.

As a result of the management practices of the TWRA, along with angler cooperation, Dale Hollow has returned to the glory days when it was the king of all smallmouth venues.

Keep in mind, slot limits are not the best regulation on every body of water. Many lakes may benefit more from no length limits. The point of the example is to understand that fisheries biologists want quality fisheries, and even if some regulations are not understood by the general public, it does not mean they are “bad” regulations.