catchable population of bass and bluegill is to determine if there are aquatic weeds growing beneath the surface. If the water is clear enough to see three feet or more, you likely have some form of vegetation growing on the bottom. There are two basic types of underwater vegetation to be concerned with, filamentous algae (moss) and weeds (these plants have slender stems and leaves) that grow from the bottom. If either of these is present it must be correctly identified so that proper control can be achieved.

There are two types of control for aquatic weeds, chemical (there are many safe and reliable herbicides) and biological (sterile grass carp). The choice often depends upon the plant and how quickly it needs to be controlled in your lake. Proper identification is very important because not all algae or higher plants (pond weeds) can be controlled by the same methods. For example, winter algae like the slimy green Spirogyra is easily controlled by any copper-based herbicide such as Cutrine, K-Tea or even copper sulphate crystals. This algae can not be controlled by grass carp; they do not like to eat it. Other algae like Pithophora, a “cotton algae,” may be controlled by grass carp, but it is not as easily controlled by copper-based herbicides as Spirogyra. The same principal holds true for other aquatic plants, you need to know what it is before a practical treatment can be prescribed.

Why is it important to control these plants? Because they can reduce the nutrients used for producing phytoplankton (the basis of the food chain for your fish) and they increase your risks of an oxygen related fish kill. A clear, weedy or slime-infested pond is not productive, is difficult to fish, and can not be properly fertilized. Fertilizing aquatic weeds or algae makes them grow more rapidly. Weeds have to be controlled before the next step in management can begin: pond fertilization.

Pond Fertilization

Applying proper pond fertilizer to a lake has the same effect as fertilizing your garden, your lawn or agricultural crops, it increases your production. In fact, research in ponds has proven that pounds of fish produced may be increased 300 percent or more by proper fertilization. How does this happen? Pond fertilizer increases the small, green, single-cell plants called phytoplankton (this is what makes your pond have a green tint). This phytoplankton is eaten by tiny insects called zooplankton. These little insects are eaten by larger insects which are then eaten by bluegill. The bluegill are eaten by bass and BAM! You have a great fishing hole.

The more food you produce from fertilization, the more fish you can grow. It is a simple and cost effective way to boost the growth and the numbers of bluegill and bass in a lake. As with fertilizing your garden or an agricultural crop, soil pH can play an important part in determining how effective the fertilization program works. In many soil types throughout the southeast, agricultural limestone should be applied to lakes to neutralize acidic pond bottoms and make the fertilizer produce more food. Have the total alkalinity of your water tested to see if your lake requires liming.

Types of Fertilizers

There are several types of pond fertilizers. Granular fertilizers were developed for ponds during the early 1950s and the standard 40-pound bag of 20-20-5 (N-P-K) is still used by many pond owners. Granular fertilizer should never be broadcast or poured from a boat because the phosphorus can become chemically bound by the bottom mud and will not dissolve. Granular fertilizer should be placed on a platform that is about 18 inches below the pond surface. It would take 200 pounds of granular fertilizer for a five-acre pond. 

Liquid fertilizers, such as the green 10-38-0, have been used with good success. This fertilizer is much heavier than water (13 pounds per gallon) and must be mixed with water before being applied to the pond, otherwise it will layer on the bottom. Although effective, it is very messy and usually requires mixing one gallon of fertilizer to four gallons of water. Once mixed, it can be poured from a boat or broadcast from the bank. A five-acre pond would require five gallons of liquid (65 pounds) plus 20 gallons of water (160 pounds).

There is a new type of concentrated, totally dissolvable powder or crystal fertilizer that requires no mixing, no platforms and only takes five pounds per acre to apply. Pond fertilization could not be easier. Formulations vary from 10-52-4 to 12-48-8 and one of them, Perfect Pond Plus (12-48-8) contains a micronutrient package which is beneficial to many crops. This fertilizer, which has the consistency of powdered sugar, can be broadcast from the bank or a pier or may be poured from the side of a boat. A five-acre pond requires only 25 pounds as compared to 200 pounds of granular or 65 pounds of liquid (plus 20 gallons of water). 

With the new powdered fertilizer, a five-acre pond could be fertilized from a single location if applied with a breeze at your back. This fertilizer dissolves in the upper two feet of the pond and can be distributed throughout the pond by wind currents. Most ponds require applications every month from March through October. Do not fertilize if the water visibility is less than 18 inches.

Supplemental Feeding

The third management technique is to feed the bluegill in your pond a floating game fish food or a small floating catfish pellet. Feeding should begin in March and continue through November in much of the southeast. For most pond owners, feeding by hand is not as efficient as using an automatic fish feeder which can feed multiple times a day. The automatic feeder never has to take the kids to soccer practice and always feeds on time, even in the rain. Bluegill have a short intestinal tract and benefit from multiple feedings during the day. In the spring and early summer, feed four times daily. During the heat of the summer, feed only in early morning and late afternoon. As the water begins to cool in the fall, feed four times daily. Bluegill experience their most rapid growth in the spring and fall. How much should you feed? Let the fish tell you, if there is feed left on the water after five minutes, you are feeding too much.

An automatic fish feeder is one of the best investments a pond owner can make. It is always a place to concentrate and grow the largest bluegill in the lake. It is also a great place for kids to learn to fish, because the action is always fast. If you place the feeder on a dock or pier, it is a convenient location to watch your fish feed and observe their growth. That is fun and a great opportunity to show your trophy bluegill to your friends.

Selective Harvest

Fishing can be enjoyable for the entire family. Don’t be afraid to keep bluegill and bass to eat, harvest is an important part of any management plan. In most fertilized ponds and lakes, bass harvest should be 15 to 25 pounds per acre per year. More than 75 percent of lakes today have too many small bass because there has been inadequate harvest. Bass harvest should be selective, remove the size bass that is the most abundant. For the average lake in the southeast, bass 14 inches and under should be harvested.

Bluegill should also be harvested; however the old adage that you can’t catch too many bluegill is not true. Allow you and your friends to take the bluegill you want to eat, but do not harvest more than 50 pounds per acre if you want to continue to catch big bluegill.

Managing your lake is not complicated or expensive. Put a little effort toward improving your lake and let’s utilize that wonderful resource you have on your property. For specialty fisheries, such as trophy bass or trophy bluegill, consult a professional fisheries biologist. An excellent source of pond management information is the quarterly magazine, Southern Ponds and Wildlife, www.southernpondsandwildlife.com. 

Barry W. Smith is a Certified Fisheries Biologist and co-owner of American Sport Fish Hatchery. He has authored numerous articles and publications on pond management and is the editor of ‘Southern Ponds and Wildlife’ magazine.