Disentangling the origin of chemical differences using GHOST
Pond management
1. POND CONSTRUCTION
One of the first principles of good pond
management is the proper construction of
the pond. Poorly constructed ponds are
hard to manage. Water levels may change
dramatically if there is seepage or if the
watershed area is not large enough.
Shallow areas may cause aquatic weeds
to grow and spread rapidly. In addition,
erosion and contamination from the
watershed may make pond management
difficult or impossible.
2. BASIC PRINCIPLES OF FISH POND
MANAGEMENT
Good fishing in farm ponds depends on an understanding
of and the ability to follow some basic rules. To properly
manage farm ponds for fishing, you should be aware of
some simple guidelines:
•proper pond construction and watershed management;
•removal of unwanted and overpopulated species of fish;
•liming and/or fertilization;
•fish species selection and stocking;
•harvest and record keeping;
•evaluation of pond balance; and
•weed control.
3. POND FERTILIZATION
Just as you would fertilize fields to increase crop yields,
you should fertilize a pond to provide phytoplankton with
adequate nutrients for growth. Proper fertilization
increases food availability throughout the food chain and
indirectly increases the total amount of fish a pond can
support. Ponds should be limed before fertilizer is
applied. Liming is important because it increases pH and
alkalinity. Even without fertilization, this may improve
available nutrients which can support a phytoplankton
bloom.
4. Water Quality
Pond dynamics are also affected by water quality. Factors
such as pH (whether the water is acid or base), alkalinity,
and dissolved oxygen affect fish health and pond
productivity. Some aspects of water quality fluctuate
daily, weekly, or monthly. Dissolved oxygen and pH cycle
each day. Alkalinity can change over a period of time,
ranging from several weeks to months, depending on the
pH of the watershed or soils on the bottom of the pond.
5. SPECIES SELECTION AND STOCKING
The choice of fish to be stocked depends on the pond owner’s
goals. The largemouth bass and bluegill sunfish combination is
the most common strategy for stocking ponds for recreational
fishing in South Carolina. The beauty of the bass-bluegill system
is its simplicity. In a well-fertilized pond, zooplankton and insect
larvae will be plentiful enough to supply food for young bass and
all sizes of bluegill. Bluegill grow rapidly and reproduce repeatedly
throughout the spring and summer. The bluegill provide bass with
an abundant food supply (forage).
8. STOCKING
•After satisfying the physics-chemical nature of the water and
plankton growth in the nursery pond, the spawn can be stocked
in the ponds at the rate of 5-6 million spawn/ha. However,
higher densities of 10-20 million/ha can be followed in cement
cisterns
•The stocking should be done either in the early morning or late
evening after gradual acclimatization of the spawn to the pond
water.
•In nursery, monoculture of carp species is usually
recommended.
10. POST-STOCKING POND MANAGEMENT
•Maintenance of one meter water depth is enough in nursery
ponds.
•Among the chemical properties, 3-8 ppm dissolved oxygen is
good for stocking spawn. Carbon dioxide above 15-20 ppm is
lethal to fish life. A pH ranging between 7.5 to 8.5 is highly
productive. The total alkalinity of 100-125 ppm is highly
productive in water. 0.2 to 0.4 ppm of phosphates is good for
plankton production and 0.06 to 0.1 ppm nitrates are considered
enough for fish growth.
•1 mg of plankton in 50 liter of water in nursery ponds is
considered to be conducive for stocking spawn.
11. FEEDING
•After stocking, during one or two days most of the plankton will
be consumed by the spawn.
•Survival and growth of spawn are influenced by quality and
quantity of food available in the pond.
•To ensure healthy growth of spawn, artificial feeding is
necessary and is restored from the next day after stocking.
•The feeding schedule is as follows.
•1-5 days after stocking - double the initial body weight of the
spawn.
•6-10 days after stocking - thrice the initial body weight of
spawn.
•11-15 days after stocking - three to four times the initial body
weight of the spawn.
12. HARVESTING
•In 15 days of nursery rearing, the spawn grows to 20-30 mm
size fry. At this stage, these fry could be transferred to rearing
ponds.
•Supplementary feeding should be stopped a day before
harvesting.
•The harvesting should be carried out in the early morning.
13. POND TREATMENT METHODS FOR
ERADICATION OF PREDATORY AQUATIC
INSECTS
Treatment method Dose/ha
Soap oil emulsion 56 kg vegetable oil + 18 kg soap
Diesel oil 50 – 60
Kerosene oil 80 – 100
Turpentine oil 75
Diesel emulsifier Diesel 50 * emulsifier 37.5 ml + water 2
14. NURSERY POND MANAGEMENT
Small water bodies of 0.02-0.10 ha with depth of 1.0-1.5 m are
preferred for nurseries though areas up to 0.5 ha can be used for
commercial production. Drainable or non-drainable earthen ponds
and cement cisterns are the different systems used for nursery
rearing of fry. The different steps involved in nursery raising of fry
are discussed hereunder.
15. PRE-STOCKING POND PREPARATION
Clearance of aquatic vegetation: Abundant growth of vegetation is
undesirable in fish ponds as they absorb nutrients arresting the
pond productivity, help in harbouring the predatory and weed
fishes/insects hindering the free movement of fish and netting
operations. Hence aquatic weed clearance is the first operation in
pond preparation. Generally, manual methods are only used in
nursery and rearing ponds, as they are shallow and small in size.
In bigger ponds mechanical, chemical and biological methods can
be used for eradication of aquatic weeds.
16. FRY-FINGERLINGS REARING POND
MANAGEMENT
Ponds of comparatively bigger in size than that of nurseries and
preferably up to 0.2 ha area is used for rearing pond, i.e., for
rearing fry to fingerlings. The different steps involved are as
follows:
17. STOCKING OF FRY
Determination of the rate of stocking depends mainly on the
productivity of the pond and the type of management measures to
be followed. The normal stocking density of fry suggested for
rearing ponds is 0.1-0.3 million/ha. While nursery phase is limited
to monoculture, rearing phase involve polyculture of different carp
species similar to that of grow-out production.
18. CONTROL OF AQUATIC INSECTS
Aquatic insects and their larvae compete for food with the young
growing fish and also cause large-scale destruction of hatchlings
in nurseries. Application of soap-oil emulsion (cheap vegetable oil
@ 56 kg/ha with 1/3 its weight of any cheap soap) is a simple and
effective method to kill the aquatic air-breathing insects. Kerosene
@100-200 l or diesel @75 l and liquid soap @ 560 ml or
detergent powder @ 2-3 kg per hectare water area can be used
as substitute to make the emulsion.