The
Gulf of Kachchh reefs (22º15`-23º40`N; 68º20`-70º40`E)
are the northernmost of India.
The
coral growth occurs in the form of fringing reefs on the wave-cut
sandstone banks around 32 islands among the 42 that adjoin the
southern flank of the Gulf. 
Because
of the geographical isolation and the extreme environmental variations
(temperature range 15-35ºC, salinity range 25-40), strong
tidal currents and the heavy sediment load, the diversity of corals
is quite low: 37 species under 23 genera. All coral species are
massive or encrusting, with a total absence of arborescent and
racemose forms.
Noteworthy
associated ecosystems are the mangroves and algal beds. The mangroves
occur in dense strands in most of the islands and as stunted patches
along the coast.
The reefs were in healthy state until early 80s when industrial
development became intensive along the southern coast. Dredging
of coralline sands for cement industries and the impacts of onshore
developmental activities were responsible for the reduction in
the density of corals. Another cause for loss of coral cover is
the extensive deforestation of the mangroves along the coast.
The silts washed onto the corals has killed a large fraction of
intertidal corals.
All
the island reefs and the intertidal expanses with corals have
been declared as Gulf of Kachchh Marine National Park.
GULF
OF KACHCHH --- GULF
OF MANNAR ---
LAKSHADWEEP ---
ANDAMAN & NICOBAR ISLANDS
GULF
OF KACHCHH