Pond Management: Managing Fish Populations
The purpose of fish management is to provide good fishing. Pond owners must decide what they want from their pond and tailor their management to meet their goal(s). Ponds less than 1 acre in size are difficult to manage for bass and sunfish. For ponds larger than 1 acre, a largemouth bass/bluegill fishery is the most popular option for Virginia ponds. Other options for ponds larger than 1 acre may include managing for trophy bass, trophy bluegill or trout. Consult your local fisheries biologist to discuss them.
All ponds have a maximum weight of fish the pond can support. In unfertilized ponds, you should be able to harvest up to 40 pounds of adult bluegill (about 120 fish) and 10 pounds of adult bass (about 8 to 10 fish) per acre per year. In fertilized ponds, you can harvest 160 pounds of bluegill (600 to 700 fish) and 35 to 40 pounds of bass (30 to 35 fish) per acre per year.
In new or reclaimed ponds, do not allow bass harvest for at least 2 years after stocking to let the bass mature and reproduce. Bass are easy to catch, and in small ponds it is possible to harvest 70-80% of the bass in 1 weekend of fishing. Harvest 5 to 10 pounds of bass per acre per year. Restricting bass harvest will help keep the fish population balanced (the proper ratio of predator and prey fish). In a balanced pond, 40-60% of the bass should be 12 inches or longer, while 20-40% of the bluegill should be 6 inches or longer. A good rule of thumb for maintaining balanced bass/bluegill populations is to remove at least 4 to 5 pounds of bluegill for each pound of bass removed. Keep all bluegill caught. Most over-population problems are caused by small bluegill, and returning them only adds to the problem.
Removing too many bass usually causes bluegills to become overpopulated and stunted. Overpopulated ponds are full of 3 to 5 inch bluegills that are thin and slow growing. Management options to correct this problem include:
- winter water level drawdowns to increase bass predation on bluegills;
- stocking additional predators;
- draining the pond and re-stocking;
- applying rotenone (fish toxicant) to kill a portion of the population;
- seining to remove excess stunted bluegills.
Catfish and trout can be harvested without limits in ponds because their populations are maintained by stocking, not reproduction.
Keep accurate records of numbers and sizes of fish caught; see this example form for keeping catch records. These records will help you evaluate the status of your fish populations (see Table 5). Fish population balance can also be checked using a 15 foot long minnow seine 4 to 6 feet deep with ¼-inch mesh. Seine 3 to 4 shallow areas of the pond in June or July. The areas seined must be clear of brush and weeds. Table 6 will help you evaluate fish population balance using seine data.