Date:12/10/2008 URL: http://www.thehindu.com/2008/10/12/stories/2008101258071300.htm

National

Low oxygen leading to high fish mortality

Shastry V. Mallady and C. Jaisankar

MADURAI/RAMESWARAM: Studies conducted in the waters of the Gulf of Mannar point to low levels of oxygen leading to high mortality of fish.

The Regional Centre of Central Marine Fisheries Research Institute (CMFRI), Mandapam, has found out that this is due to the blooming of a harmful marine, dinoflagellate (noctiluca scintillans), a minute marine species.

Another study undertaken by Madurai Kamaraj University’s Centre for Marine Studies has revealed that oxygen levels have depleted due to outbreak of ‘red tide’ phenomenon caused by blooming of organisms, which discolour the ocean surface.

The massive blooming of the organism has reduced the oxygen level in many of the landing centres between 1 and 1.2 ml per litres as against the normal level of 4.5 to 5 ml, causing breathing problems for fishes, the CMFRI study says.