Coarse and Ornamental Fish Supply
and Control
Existing ponds may already hold an untapped harvest
of fish, probably long since stunted.
Or they may contain shoals of uncommercial species
like small roach. Other
ponds may have become too shallow due to silting, or be polluted
with farm run-off.
Markets
Coarse fish
are stocked for angling: mirror carp, green tench,
bream.
For conservation: roach, rudd, gudgeon
- e.g. to feed kingfishers, otters, etc.
For aquatic weed control : grass carp
eat twice their own body weight of aquatic weeds/day, above
18deg.C and are stocked to control blanket weed, duck
weed or Canadian pond weed. Ornamental fish
such as golden orfe, golden rudd and koi carp
are stocked purely for visual enjoyment.
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Aquatic Plants and Reedbeds
Waterplants
can be very invasive so plan species planting carefully.
Consider height, depth and colour. Excessive weed growth may require aquatic herbicide.
These are species specific and harmless to wildlife if correctly
applied. Reedbeds provide diverse aquatic habitat
as well as acting as a natural filterbed. This can
neutralise pollution, prevent ponds silting up and check
algae growth or green water.
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Harvesting Fish
Unmanaged ponds can yield surprisingly high, or
disappointingly low harvests.
Seine netting can be an effective method
of harvest, but draining or lowering the level of
the pond is far more effective. Electrofishing has
limited use in canals and rivers but seldom in ponds.
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