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Volume :32 Issue : 2 2005
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Grey mullet mortaility caused by oxygen depletion along theGulfs coastal region of Kuwait
Auther : SAMIR S. RADWAN, REDHA H. AL-HASAN, ABDEL-MAJEED SAFER, ABDUL HADI BU-OLYAN AND MOHAMED ELIYAS
Departments of 1Biological Sciences and 2Chemistry, Faculty of Science, Kuwait University, PO Box: 5969, Safat-13060 Kuwait.
* Corresponding author
ABSTRACT
Comparative oceanographic, chemical, biochemical and microbiological analyses of coastal water samples from six stations along Kuwaiti coasts through 2001, the year of grey mullet kill, and 2002 indicated that oxygen depletion in the water most probably resulted in the August 2001 mullet kill. Water samples collected in 2001 revealed higher levels of nitrates and phosphates and consequently, more phytoplanktonic microorganisms (eutrophication) than samples collected in 2002. Water samples were also richer in aerobic bacteria in the summer of 2001 than in 2002. The mullet kill in August 2001 was associated with the highest recorded water temperature and biochemical oxygen demand (BOD) values, and the lowest dissolved oxygen contents of the water. Although maximum temperatures in August 2002 were similar to those of August 2001, neither BOD or dissolved oxygen values exhibited extreme (maximum for BOD, minimum for oxygen) levels in 2002. Fish kill experiments in the laboratory suggested that oxygen depletion associated with high water temperatures, organic matter, and aerobic bacteria levels resulted in a mullet kill along the Kuwait Gulf coast.
Keywords: Arabian Gulf; coastal waters; eutrophication; fish kill; gray mullet; oxygen depletion.