International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
The accuracy achieved is about 85 per cent. The branching coral,
massive coral, healthy and bleached coral have distinct spectral
characteristics. However, their distinction using remote sensing
data has not been very successful.
3.4 Protected Areas
Many ecologically fragile areas are designated as ‘Protected
Areas’ to preserve and conserve such ecosystems. However, it is
not known, how much area will be sufficient for conserving
biodiversity in vital/critical habitats, such as mangroves, coral
reefs and wetlands. It is necessary to monitor these areas to assess
impact of conservation measures as well as anthropogenic
activities. The repetitive coverage of the IRS satellites is quite
adequate for monitoring such changes. In one such study, in the
Marine National Park, Jamnagar, on the Gujarat coast significant
changes in the mangrove vegetation and coral reef area were
observed during the period 1975 to 2000 (Nayak et al. 1989,
Nayak and Bahuguna, 2001). Degradation and loss of both
ecosystems continued till 1985 on account of mining of coralline
sand and use of mangroves as fuel and fodder. The loss of coastal
habitats is a direct measure of declining condition of biodiversity
in coastal habitats. Hence, In 1983, this area was declared as a
marine park (protected area). Extensive measures were initiated
for conservation of mangrove and coral reef areas by the marine
park authorities. This resulted in reversing the trend of
degradation after 1985 and has certainly helped towards restoring
the environment (Fig. 4). However, recent industrialisation,
development of ports, etc. have again put these ecosystems under
stress, as evident from recent satellite data. Remote sensing data
has been proved to be extremely useful for routine monitoring of
the protected areas.
Status of Coastal Habitats of Marine
National Park, Gulf of Kachchh (using
300
satellite data)
19750 1198619931 99820008
—O- Total mangroves
—"Sparse mangroves *“— Reef.
=O Dense mangroves
Mud over reef
Fig. 4..Syatus of coastal ecosystems in the Marine National Park,
Gulf of Kachchh, India.
3.5 Marine Fishery
Marine living resources provide animal protein requirement of
human being. Fishing and aquaculture are major source of
employment and economically very important, especially in
developing countries. The assessment of stock: is one of the
important activities for conserving the marine living resources.
India has high potential for marine fisheries development. The
present fish production in the country is mainly from the coastal
waters (up to depth of 50 m). An improved knowledge of
identification of marine living resources in EEZ is required to
harness full potential of commercial fishery. Phytoplankton forms
the first link in the ocean food chain and gives an indication about
the standing stock of green biomass, which helps in predicting the
third level productivity. Today, satellite-based observing systems
having narrow spectral bands in the visible region are providing
better insight into our understanding of the ocean productivity.
They also provide better understanding of the role played by
ocean productivity in the uptake of carbon dioxide from
atmosphere.
IRS P4 Ocean Colour Monitor (OCM) has been providing ocean
colour data every two days for the Indian regions. The potential
Fishing Zone (PFZ) maps are generated based on oceanographic
features such as thermal boundaries, fronts, eddies, rings, gyres,
meanders and up welling regions (Narain et al. 1992, Solanki et
al. 2003). The chlorophyll and SST, derived from OCM and
NOAA AVHRR have been integrated to provide fishery forecast
to predict likely availability of fishes more accurately (Solanki et
al. 1998, 2001, Dwivedi, et al. 2002). The ocean colour data
provide information about the availability of food in a column.
The SST defines the environment of the ocean. It was observed
that wherever, the boundaries/fronts/gradients of the chlorophyll
and SST coincide are ideal sites for the fish aggregation. Such
sites are the indicate coupling between biological and physical
processes, and hence fish tend to aggregate. These forecasts are
valid for three days and are updated every second day. It was
observed that this technique is quite useful for pelagic and
demersal fishery (Fig. 5). In India, this technique is operationally
used and forecasts are provided to about 240 fishing harbours
routines by the Indian National Centre for Ocean Information
Service (INCOIS), Hyderabad.
It was observed that such forecast are 70-90 per cent accurate
results in 70-100 per cent increase in catch, both pelagic and
demersal (Solanki et al. 2003). The benefit to cost ratio has
increased from 1.3 to 2.1 for those fishermen who have used
satellite-based fishery forecast (Nayak et al. 2002) The
information on sea-surface wind is being integrated to increase of
validity of forecast. Initial results indicate quite a good promise.
Apart from this, new resources through sea ranching and mari-
culture in enclosed and semi-enclosed bodies will have to be
tapped. Efforts are continuing to predict primary productivity and
link it to fish stock using ocean colour data. The bio-geographical
zoning of the Indian waters is under progress. All these efforts
will lead to achieve food self-sufficiency in developing countries.
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