Andamans, L'dweep may lose reef-building corals
Surinder Sud / New Delhi November 02, 2009, 0:49 IST
http://www.business-standard.com/india/news/andamans-l%5Cdweep-may-lose-reef-bui\
lding-corals/375011/

Climate change to also majorly affect fish catches in our seas, rivers.


Climate change and a rise in sea temperature may result in the
disappearance of reef-building corals along the Lakshadweep and Andaman
and Nicobar coasts in 10 to 50 years. The distribution and harvest of
different fish species in the Indian seas and major river systems may
also alter perceptibly.

Sea surface temperature is anticipated to rise about three degrees by
the end of this century. This is likely to impact marine flora and fauna
in a major way.

This has been indicated by studies conducted under an elaborate
“national network project” on assessing the impact of global warming and
climate change on the Indian agro-ecosystems, launched by the Indian
Council of Agricultural Research (ICAR). Around 15 research institutes
are studying how agriculture, fisheries, livestock and other sectors
will be affected and what can be done to mitigate the effect.

Coral reefs are known to be highly sensitive to climate influences and
are among the most vulnerable of all marine living beings to temperature
changes. Reef-building corals are currently the dominant creatures in
the coral diversity in the Indian seas.

The ICAR studies have projected that the reef-building corals are likely
to fade away as dominant organisms between 2020 and 2040 in the
Lakshadweep region and between 2050 and 2060 in the Andaman and Nicobar
waters.

These projections have taken into account only the effect of warming of
ocean water. But since the rise in water temperature is also likely to
be accompanied by an increase in the acidity of sea water, the adverse
effect on corals may actually be worse. Higher acidity would dissolve
the calcium carbonate that forms the skeleton of the reefs.

The studies on the effect of sea water warming on marine fisheries have
revealed that some significant changes in the distribution of the fish
species are already underway. The presence of oil sardines, which abound
Indian coastal waters, has been extended to beyond their known
boundaries in the.

Oil sardines did not exist in the northern and eastern latitudes along
the east coast before 1976 but they are found there now, because the
water temperature is now conducive to their survival.

“It is expected that the distribution of sardines may extend further to
Gujarat and West Bengal coasts in the coming years, assuming that other
fisheries-related physical and biological parameters will not vary
considerably”, maintains P K Aggarwal, ICAR National Professor, who is
engaged in compiling the results of the climate change studies.

However, if the sea surface temperature on the southern side increases
beyond the optimum levels for fish, it may drive the fish population
away from this zone, resulting in reduced catches along the south-west
and east coasts.

Where river fishery is concerned, the studies have recorded some
significant changes in fish stocks in the Ganga river system. The
changes in the water flow patterns as a result of the factors related to
climate change has lowered fish spawn (eggs) availability. Leading to
erratic breeding of fish in the Ganga river. The fish landings have,
consequently, declined from, on an average, 85.2 tonnes in 1959 to 62.5
tonnes in 2004.

Besides, there is a noticeable shift in the geographical distribution of
fish in the Ganga. The warm water species (such as Glossogobius giuris,
Punitius ticto and the like), available earlier in the middle stretch of
the river, are now found in the relatively colder stretch of the river
around Hardwar. This is attributed to the rise in river water
temperature in recent years.