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C. F. HICKLING
11. SUITABILITY OF ESTUARIES AS SITES FOR FISH FARMS
A. Their topography
1. Enclosed nature
The generally enclosed nature of estuaries, and especially the
presence of bars or middle grounds, ensure fairly well-sheltered water
with resulting absence of heavy surf liable to damage the farms. An
exception is the liman of the Black Sea, where the natural sand bar
which defines the lagoon faces the sea and is liable to be damaged and
eroded with the mass-transport of sand.
FIG. 1. Repairing the banks in a Javanese fishpond. Note shallowness of water, and
sluice gate with turnbuckle, screened against the escape of fish. Main feeder canal
t o left, with a wading cast-net fisherman.
Even in enclosed estuaries, erosion due to the rise and fall of tide,
to flooding, and the strong currents associated with them, and to the
ceaseless lapping of small waves, may entail much upkeep, such as,
for example, rebuilding and revetting embankments (Fig. 1). This is the
more so, because a close cover of plants, such as can easily be grown
on the banks of fresh water ponds, is not always possible on the
embankments of saline or brackish ponds.