PLATEAU LAND AND WILDLIFE MANAGEMENT NEWS

Plateau Land and Wildlife Management

Wednesday, March 23, 2011

FISH MANAGEMENT: A PRIMER

by Craig Bowen, Business Development Coordinator, Plateau Land & Wildlife Management

Many men go fishing all of their lives without knowing that it is not fish they are after.


Henry David Thoreau was a wise man, and the "wise" fishermen among us recognize that as fishing season approaches, their wildlife water features (colloquially known as ponds, lakes, and tanks) may need some attention. At Plateau, we believe holistic ecosystem management is the best approach for managing land and wildlife, and that philosophy also applies to managing your wildlife water feature. To paraphrase Mr. Thoreau, many landowners build ponds, lakes, and tanks without knowing that they are not properly managing for fish.

To wisely manage your wildlife water feature for fish, these three areas must be monitored: habitat, water quality, and population health.

Habitat
Unless artificial habitat was included in the construction of your pond, most of the structure fish use for protection probably comes from natural aquatic vegetation. Aquatic vegetation presents a unique quandary -- some vegetation is required for a successful ecosystem, but certain types of vegetation can making fishing difficult. There are four basic types of aquatic vegetation: algae, submerged plants, emergent plants, and floating plants. Each type presents species which are highly beneficial to wildlife by providing food and shelter, and all must be managed carefully to maintain a healthy balance between "fishability" and good habitat.

Some of the common native aquatic species in Texas ponds are sago pondweed, southern naiad widgoengrass, and coontail. These are all easily identifiable and beneficial plants in moderation, but can all be invasive under certain conditions. Aquatic vegetation may be managed through the use of chemical (herbicide), biological (triploid grass carp), or mechanical (rakes, seins, etc) methods. Each species responds differently to each method, so be sure to understand your goal and your vegetation before implementing an aquatic vegetation management regime.

Water quality

Water quality in fisheries management is often a discussion of water clarity. Water clarity is affected mainly by microbial plant growth called algae, a type of phytoplankton. Phytoplankton is a large group of microscopic plants which compose the base of the aquatic food chain. Like most plant life, algae are photosynthetic, and the chlorophyll in the plant cells is green. High levels of algae during certain times of year, referred to as "algae blooms," give clear water a green hue. Very clear lakes generally have low levels of phytoplankton, and oftentimes exhibit poor success of all predatory fish such as bluegill and bass because of the lack of a food chain base. If this is the case in your pond, it may be time to visit with a consultant like Plateau about fertilizing your pond, which is a great way to create algae blooms.

Turbidity, which is a measure of Total Suspended Solids (TSS) in the water, also affects water clarity in some cases. High levels of TSS result in "brown" or "dingy" water, and prevent sunlight infiltration, which inhibits valuable plant growth. The measure of the acidity or basicity of an aqueous solution is called "pH." Varying pH levels may affect turbidity, and there are simple and economical remedies to pH problems.

There needs to be some attention given to the chemical composition of your pond water, particularly nitrate, phosphate, and silicic acid levels. Because most rainwater is chemically balanced naturally, and also thoroughly filtered through grass and other vegetation before reaching the pond, most ponds test in the "acceptable" range of actual water quality due to the high levels of rainwater which make up the pond water. Nevertheless, conducting water quality tests every 5 years is advisable.

Population health
Population health is the easiest and most fun part of fisheries management. If a lot of small bass (1 pound or less) are caught from a pond, remove most of this size fish you catch for one year. If the bass look "skinny," remove about 30 pounds of fish for every surface acre of water in one year and test the results. If only large fish are caught (greater than 3 pounds), remove up to 50% of this size fish you catch for one year. Keep in mind most private ponds can only sustain one trophy fish (greater than 5 pounds) per acre, so realistic expectations regarding bass size are important in private fisheries management.

Whether you are managing a world class bass fishery, or simply want your grandchildren to have a place to have some summer fun, there are multiple management considerations. With these concepts in mind, your wildlife water feature will be more productive, more beautiful, and more enjoyable for generations to come.

To wisely manage your wildlife water feature for fish, these three areas must be monitored: habitat, water quality, and population health. Photo by Lee Kothmann.