Improve the Fishery

Improve the Fishery

The health of an aquatic ecosystem can be evaluated using many important criteria; water quality, species diversity, habitat diversity, littoral zone features, and other parameters. As the quality of each improves, so too does the overall ecology of the entire ecosystem. Of course, the opposite is true as well, a reduction/decrease in the quality of a single criterion, will likewise, reduce the health of the ecosystem. The subject of this discussion centers on the quality of the fishery as it relates to the ecological aspects which promote healthy fish populations.

The habitats an aquatic ecosystem provides are critical to the success of the fishery. All species of fish need places to feed, nest, live, and find protection. This includes forage fish, game fish, larval fish, fry (baby fish), and juveniles. Depending on the size of the fish, they need different habitats. Generally, the littoral zone, (shoreline to around ten feet) represents the most important area for all fish sizes, but especially for small fish. In a typical lake, the littoral zone is comprised of different native species of aquatic plants, which provide food, nesting, egg hatching, and protection, as described under the “Ecology/Fishery” menu item in the “Ecology/Fisher Primer” dropdown—please see that section if you haven’t already, for that information will not be repeated here.

When there exists little or no natural aquatic vegetation in the littoral zone, it becomes more difficult for fish to make a living, reproduce, and increase their population numbers. This can still happen, but at a reduced rate, since the there is less food, protection, and nesting sites available. When there is little or no vegetation, fish will look for substitute places to live, nest, look for food, and hide. These include rocks, snags, fallen trees, submerged brush, limbs, and manmade objects such as open barrels, buckets, and items such as car chassis, sunken boats, etc.

The ecology of a lake with little littoral zone vegetation can be greatly improved by revegetation with native aquatic plants. When successful, this is a lasting improvement, and will often continue to improve on its own as the vegetation successfully spreads. Revegetation success depends on a number of parameters which are more likely to be available in a natural lake setting than in a river reservoir system in which the water level has annual lengthy water drawdowns, as in Watts Bar Lake. Many native aquatic plant species cannot withstand exposed dry periods. However, invasive aquatic plant species thrive, even with dry and cold periods of exposure.

A second method to significantly improve fish habitat is to provide suitable manmade structures. There are any number of types of small and large structures that can be easily constructed and placed in the lake. Smaller structures can be placed in the shallower areas, and larger one in deeper water. They can be made with native terrestrial vegetation such as brush, small trees, limbs, bamboo, etc. weighted to hold on the bottom. They can also be made of concrete blocks, PVC pipe, wood, old pallets, etc. Just a few of these structures will result in an increase of fish numbers and diversity in that area. Manmade structure will provide many of the same benefits as littoral zone vegetation and last many years. Below are photos of a few structures various individuals and fishing clubs have devised and installed.

Fish of all sizes and species require a variety of habitats to make a living, and these structures go a long way toward providing needed places to thrive. Fish are not picky, they just need a place to live, natural or manmade.

However, even these valuable habitats will not be available when they too are taken over by invasive aquatic plants. Dense mats of invasive species will remove the entire area within the plant mat from use by fish, no matter the type or quality of the habitat before the arrival of the mat.