06-bioresourcesstatu.. - M. S. Swaminathan Research Foundation

area being used as bricks for building houses. A
thin mixed layer of organic material deposit was
discovered just above the hardpan showing hereby
that hardpan does not allow the colloidal material
to percolate down. White coral sand is found
below this hardpan. No hardpan exists in the
marshy or wetland and depression in these
islands.
Ground water: Freshwater resources are limited.
The hydrological system is extremely fragile. The
water is contained in a freshwater lens 1.5 m.
below the surface. The water is periodically
renewed by rainfall. Conserving and protecting it
from pollutants is very important. It will be very
expensive to replace this resource, if depleted.
Figure 2 - The Hydrological Cycle
The islanders explained that fishes like kalatha
kunni and farat as well as karadi (tortoise) and
panjari (dragon fly) are extremely beneficial in
maintaining clean water supply and in keeping
the mosquito population down by eating the
mosquito larvae in the open water bodies. Kalatha
kunni and faral are introduced into new wells
and in this way their population is maintained.
The islanders protect these fauna and do not
allow anyone to harm them. In recent years,
however, the population of all these species has
come down to the point of needing to include them
in the endangered list. The islanders maintain
that this is because the agriculture department
has introduced bleaching powder into the ponds
and wells, and spray DDT to control the
mosquitoes. The water bodies have been thus
polluted and the population of the beneficial
insects and fish has drastically declined (Hoon,
V;1996).
b. Reefs and Lagoon
Coral reefs of the Islands are mainly atoll except
one platform reef at Androth. Almost all the atolls
have a NE-SW orientation with the island on the
east, a broad well shaped reef on the west and a
lagoon in between. These -lagoons are protected by
reefs on the outer edge, and provide a safe
anchorage for small vessels. The reef on the
107
--1-,
Lakshadweep Islands
ell:stern side is closer to the island and the lagoon
is very shallow. The coral patches in the eastern
lagoon are expos~d during low tide. The eastern
reef flat faces the highest stress from trampling by
reef gleaners and net operators since it is easily
accessible by foot.
The reef flat occupies an area of 136.5 km'. Sea
grass occupies 10.9 km' and lagoon occupies 309.4
km' (Bahuguna and Nayak S, 1994). The depth of
the sea increases outside the coral reef and can
reach upto 1500-3000 m. Andrott is the largest
Island with an area of 4.84 km' and the only
Island that does not have a Lagoon.
Figure 3 - The Ecosystem profile
.•••. ~"-.!.. "••.•.
~ -.of -. 'lloo,>.s-
On the leeward side the reef slopes into the sea.
The first plateau is found around a depth of 5-6 m.
The second plateau with the sandy patches is
found around 25m - 30 m (Andreas, 1997). This
area is locally called the bar area, where one can
witness the variety of the coral formation in all
their glory and species variety. The fishermen
favor this bar area, for harpooning and spearing
specific kinds of Rays and big fish. This bar area
is around 200 m around the reef.
During high tide water exchange takes place
between the lagoon and the open sea over the reef.
The lagoons have sand bottoms with scattered
coral boulders and pinnacles followed by extensive
sea grass beds at the landward side. The lagoon
opens to the sea through one or more natural
entrance points. These are natural breaks in the
reef that allow boats to ply between. the ocean and
the lagoon. There are other small shallow
entrances, locally known as chals. The chals are
important since these are the points where the fish
shoals enter and leave the lagoon with the tidal
change. These chals are therefore favored reef
fishing spots for net operators and are used by the
fishermen during the monsoon season.