Bluegills play a dual role in Iowa farm pond management by providing most of the "take home" catch and also a major portion of the forage for largemouth bass. A bluegill rarely exceeds one pound in weight, but pound for pound it is the sportiest fish around. The average size caught by most anglers is 6 to 7 inches in length and 1/4 to 1/3 pound in weight. The average bluegill life span is about five years, but 13-year-olds have been recorded. Bluegills have a tremendous reproductive capacity and may become to numerous for their food supply, seldom growing too 6 inches when this happens. Bluegills reach sexual maturity at age one with a 4-inch female producing about 4,000 eggs.
Spawning takes place from May through late August. Male bluegills construct nests (shallow depressions) in shallow water and drive a female to the nest to lay eggs. After fertilization the male guards the eggs and nest during incubation which takes 2 to 5 days. He continues to guard the newly hatched fry until the yolk sac is absorbed and the fry swim off. He then discontinues parental care.
The best stocking rates and schedule for Iowa farm ponds have been determined from numerous pond experiments. Bluegill fingerlings are stocked at 750 to 1000/surface acre in autumn. Rapid fish growth can be expected from these stocked fish in all new Iowa farm ponds. Bluegills stocked in the fall when they are one to two inches long will grow to 5 inches by the next fall. Two years after stocking they will average 6 1/2 inches long.
The largemouth bass is the trophy fish in farm ponds and is also the major predator of young bluegill. A past state record largemouth bass, which was caught from an Iowa farm pond, was more than 24 inches long and weighed over 10 pounds. Under ideal conditions bass spawn in their second year of life, but most spawn in the third year of life. Male bass also build nests similar to bluegills, but the nests are larger. Spawning occurs in May and early June in shallow water. A female bass 10 inches long will produce about 2,000 eggs, but an older, larger bass can produce 15,000 eggs. Bass eggs usually take from 3 to 10 days to hatch and male bass provide parental care until the fry are about 10 days old, when parental duties are discontinued.
Largemouth bass should be stocked into a new pond in June following the fall stocking of bluegill. They should be stocked at a rate of 70 fingerlings (1-2 inches) per surface acre. June bass planting assures heavy, predation on newly hatched bluegill, very rapid bass growth and control of bluegill populations.
Largemouth bass fingerlings can be expected to reach 7 inches by October,although bass in ponds with good bluegill reproduction will often grow to 9 inches by October. In the second year, bass will average 10-11 inches, but some may reach 13 inches in length.
Channel catfish are regarded as bonus fish in Iowa farm ponds because they provide quality angling and their presence in farm ponds usually benefit the bass and bluegill populations. Channel catfish grow large in ponds with some individuals exceeding 15 pounds. Catfish become sexually mature when they are two years old, but most reproduction comes from older fish. A female produces about 4,000 eggs per pound of body weight. Spawning occurs in June when the male builds a nest similar to bass and bluegill, except it is usually more protected, and nudges a female to the nest. Male catfish also guard the nest and care for the young.
Channel catfish seldom reproduce successfully in small ponds, which is the result of predation on the young by bass and bluegill. Catfish are stocked in the fall at the same time bluegill are stocked. One hundred fish per acre are recommended which will grow from 2-inch fish to about 8 to 11 inches one year later. Two years after stocking, channel catfish should average 12 inches, with the maximum size about 16 inches. Pond research has shown about 30% of the catfish population dies each year and the population must be maintained by stocking 100, 8-inch fish per acre every 2-3 years.
Growth of stocked fish in the average Iowa farm pond
Farm ponds in Iowa are usually sufficiently fertile so that fish feeding is not necessary. Feeding may be attempted if the owner desires rapidly growing and large-bodied bluegill and catfish and is prepared to pay for the cost of feeding. More information on fish feeding,feeders, and feeds can be obtained by contacting the Iowa Department of Natural Resources.
Is your pond in "balance"?
Two years following initial stocking a pond will contain its limit of fish measured in pounds. No more weight can be grown in the pond unless you remove fish from the pond. Production will equal your harvest – remove 50 pounds and 50 pounds will grow back. However, depending on that harvest, the new population may contain a healthy number of large fish (balanced pond) or be dominated by a large number of small, stunted fish.
little fish eat littler fish, ad infinitumPonds can be checked for a balanced fish population with a 30 foot seine or by fishing. Seine hauls should be made in mid-summer.
- Hauls that contain numerous small bluegill and some bass indicate an acceptable fish population.
- Seine hauls containing young bass, but no small bluegill indicate an undesirable population with no bluegill present. Stock 20-30 adult bluegill per acre (make sure to stock males and females).
- A population with no small bass, no small bluegill and with many green sunfish, bullheads, or tadpoles is also undesirable. The pond should be drained or chemically renovated and restocked with proper species.
Rotenone for chemical renovation can be obtained from Department of Natural Resources field fisheries personnel.
Another method of checking the balance of a fish population is through fishing. Fishing effort must be sufficient to sample the available species present in the pond or it will be inaccurate.
- In a pond with too many small 3-5 inch bluegill, remove as many as possible. They can be seined or trapped out.
- A pond containing numerous bass less than 12 inches may not contain bluegill and they should be stocked. Overcrowded bass can be easily removed by angling.
- A pond that has a very large proportion of large bass (greater than 75%) is also out of balance. Large numbers of small bluegills have reduced the reproductive success of bass and no small bass are entering the population. Remove 3-5 inch bluegills by trapping or seining and stock 50 ten-inch bass per acre.
Bluegill populations with many individuals greater than 6 inches are rare and ponds containing only small bluegill are undesirable. A balanced pond will contain a bass population in which about half of the fish you catch by angling will be larger than 12 inches. (Note: bass caught by angling are generally 8" or larger).
In general, a balanced pond will have a range of sizes of bass and bluegills. Also, a pond less that 6 acres will never have a balanced crappie and bass population.