Toxic algal blooms on the rise in Indian waters

Kochi (Kerala), Feb 11 (PTI) Toxic algal blooms, which
cause mass fish mortality, are on the increase in Indian sea
waters.

It is disturbing that occurrence of algal blooms has
increased in the last 20 years causing frequent mass death of
fish, says a paper presented at an international symposium on
Marine Ecosystem here in India's southern state of Kerala.

The microscopic marine phytoplankton have very important
role in the marine ecosystems, forming food for larvae of fish
and other organisms. There are about 5,000 species of marine
phytoplanktons of which 80 are known to be toxic.

These blooms are very harmful resulting in mass mortality
of fishes such as oil sardine, the paper said.

Scientists at the Centre for Marine Resources and
Ecology, Kochi, recorded 19 blooms in the Indian seas during
1998-2006.

Intense blooms result in very low oxygen levels. The
coastal waters turn into dark green or red, it said.

The Central Marine Research Institute (CMFRI) scientists
also reported intense blooms in Gulf of Mannar in October last
year, which is believed to be the cause of the death of fish.

Reducing pollutant load in the coastal waters by treating
the domestic and industrial effluents before discharging into
the sea will greatly reduce the occurrence of blooms, it said.

Another paper pointed out that intense exploitation of
commercial marine species along the Kerala coast had led to
threats of species loss, including depletion of some species
of marine catfish and goat fish. Protection of biodiversity is
possible by demarcating marine protected areas, it said.

The CMFRI study has shown that biodiversity of the coast
of Thiruvananthapuram was stressed due to impact of fishing.

Although the seascape of much of this area is not
amenable to trawling due to rocky and uneven nature of the
bottom, trawling of Wadge bank located North off Kochi is
probably the reason for the stressful condition, the paper
said, adding protecting the area from fishing, especially
trawling, will be helpful to alleviate stress of the
ecosystem.

While the debate continues on the optimal size and
location of MPAs, a growing consensus points towards extensive
networks of protected areas of at least 20 per cent of the
habitat as per IUCN guidelines, it said.

The unique marine ecosystem in Kerala needs to be
conserved and steps are necessary to maintain it undisturbed
so as to rebuild the stressed habitats, the paper said. PTI UD
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