Causes of fish mortally along the Qatari waters (Arabian gulf)

Excessive fish mortality were observed along the Qatari coastline and offshore during the summer of 1996 and 1998. Massive amounts (about 40 tons) of dead fish were recorded off the eastern coast. Siganidae, Lethrinidae and Carangidae, coral reef inhabiting fish, were the main species observed dead along the beaches. Hydrographic parameters (temperature, salinity and dissolved oxygen) and main pollutants (ex: NH4+, TPH, BOD5, metals, PCB's and PAHs), as well as chlorophyll a were monitored. Pollutants levels during summer were around background concentrations. Thermal plumes from industrial facilities don't extend more than 2 kms offshore. Fish kills did not follow the appearance of patchy algal blooms during spring and autumn seasons. Temperatures along the Qatari coast rising to 37.0°C during summer 1996 and 38.6°C during summer 1998, seem to be the main reason for fish-kills. The 35°C are regarded as the threshold beyond which fish-kill phenomena exist. Beside the control and monitoring of landbased and marine derived pollution sources, the development of a Temperature and Red tide Watch Program in the Gulf is a must.