Managing Sport Fish Populations in Farm Ponds

Forrest Wynne, Area Extension Specialist, Aquaculture

Kentucky State University Cooperative Extension Program

P.O. Box 3327 West Somerset, KY 42564-3327 (606) 679-2090

The quality of sport fishing in a pond should be evaluated by
fishing the pond intensively. Farm ponds which contain desirable
fish populations should produce bluegills greater than 6 inches
long and largemouth bass which have an average weight of 1-2 lbs.
Ponds which produce many large bluegill (1/3 lb average), and
many largemouth bass which average less than 1 lb are probably
overcrowded with largemouth bass. If fishing produces many
bluegill 3-5 inches in length and infrequent catches of
largemouth bass greater than 2 lbs, the pond is probably
overcrowded with bluegill. If fishing has been unsuccessful,
have other fishermen fish the pond, use different baits or lures,
and try fishing at different periods during the day.

During the spring and summer when water temperatures have
reached 70 degrees F or greater, pond shorelines can be seined to
provide information describing the condition of the fish
population. A seine made of 1/4 inch bar mesh with a length of
20 feet and a depth of 4 feet should be used at 4 or 5 locations
around a pond’s shoreline. Ponds should not be sampled unless
the fish population is at least 2 years old.

If seining produces many small and nearly transparent young
of year bluegill, no young of year largemouth bass, and very few
bluegill 3-5 inches in length; the pond is likely to be
overcrowded with largemouth bass. Overcrowding of largemouth
bass can be corrected by removing bass. If the pond contains no
young of year largemouth bass, no young of year bluegill, and
many bluegill 3-5 inches in length, this may indicate a crowded
bluegill population. Stunted bluegill populations may be
controlled by shoreline seining or rotenone, or by stocking 15-20
adult largemouth bass (12 inches in length) per surface acre.
Pond renovation may be the only effective method of removing a
stunted bluegill population.

If young of year largemouth bass and bluegill are present,
and few bluegill 3-5 inches long are caught by seining, a
desirable fish population is likely to be found. Limited numbers
of largemouth bass should be taken from farm ponds since bass
control bluegill populations through predation.

Farm ponds should only contain largemouth bass, bluegill, red
ear sunfish (shellcrackers), and channel catfish. Ponds which
contain undesirable fish populations should be drained or
reclaimed with rotenone and then restocked.

Before a pond is reclaimed, the volume must be determined; in
acre feet. The average depth can be determined by taking depth
measurements, every 10 to 20 feet across the long and short axis
of the pond with a weighted tape or calibrated pole. The total
sum of the measurements (Example: 100 feet) is divided by the
number of measurements (Example: 25 measurements) to obtain the
average depth (Example: 100 feet/25 measurements = 4 feet).

The area of a large pond may need to be determined by aerial
photographs which may be examined at county Agricultural
Stabilization and Conservation Service (ASCS) offices, or by
surveying. The area of a small circular pond may be measured by
tape along the shoreline and calculated by using the following
equation:

2  (Distance around shoreline in feet)
Number  ———————————–
=       of Acres

546,906

Example: Pond A is round and measures 425 feet around its
shoreline. How many surface acres is pond A?

Solution:

2
(425 feet)         425 feet x 425 feet
180,625 feet

———–     =     —————–
=    ————-

546,906
546,906
546,906
= 0.33 acres, or one third acre

Note: 546,906 is the circumference (in feet) of a 1 acre
circular-shaped pond, squared.

The surface area of a rectangular pond is calculated by
multiplying the pond length by the pond width in feet, which
determines the area in square feet. Dividing the area by 43,560
(square feet in an acre) will determine the size in acres.

Example: A rectangular pond measures 300 feet by 290 feet. How
many acres is this pond?

Solution:

(300 feet x 290 feet)
87,000 square feet

———————     =
——————       = 2 acres

43,560 square feet
43,560 square feet

A triangular pond’s surface area is determined by multiplying
the base and height shoreline measurements, and then multiplying
by 0.5. Pond measurements can be obtained by “pacing” around the
pond. For example: if each step or stride is about 3 feet long,
100 steps would approximate 300 feet.

Pond reclamation is usually done with rotenone concentrations
of 0.1-5 ppm depending on which fish species are targeted. One
gallon of 5% liquid, or 10 lbs of 5% powdered rotenone is usually
enough chemical to treat 1 acre foot of water. Pond water levels
should be lowered as much as possible to reduce the amount of
chemical needed, and to insure a complete kill. Rotenone should
be distributed throughout the entire water column and over the
entire pond surface. The diluted chemical can be distributed
through the prop-wash of an outboard motor in large ponds, or by
a pressure sprayer in small ponds.
Rotenone works most effectively in water which has reached 70
degrees F and will detoxify in 10 days. Water should not be
released from the pond for two weeks after treatment when water
temperature is 70 degrees F. After two weeks the pond will be
suitable for restocking. The Food and Drug Administration has
not approved the consumption of rotenone killed fish for humans
or livestock.

The Kentucky Department of Fish and Wildlife Resources
requires pond owners get permission to reclaim their ponds. The
proper forms must be submitted to your conservation officer
before September 1. The Department of Fish and Game sells the
rotenone. Rotenone should be used during September – October
after the bluegill spawning season. Contact your district
Fisheries Biologist, local Conservation Officer, or County
Extension Agent for more details on pond reclamation and for
sources of fish for restocking ponds. The Kentucky Department of
Fish and Wildlife Resources has a pond management guide titled
“A Guide to the Management of Farm Ponds in Kentucky.” This
guide is useful for any pond owner and is available from the
Department of Fish and Wildlife.