Abstract
The qualitative and quantitative distribution and seasonal variation of luminous bacteria in the sediments of Vellar estuary, Porto Novo, South India (11° 29′N, 79°46′E) was studied. The luminous bacterial population ranged from 5.1×103 to 3.2×104CFU/g dry weight in station I and 2.4×103 to 9.1×103CFU/g dry weight in station II. The salinity of the estuarine water appeared to have an indirect relationship with luminous bacterial counts in the sediment. The maximum number of luminous bacteria were recorded during summer followed by a decline before the monsoon. The counts were at a low level during monsoon and then started to increase after the monsoon season. Vibrio harveyi, V. fischeri and Photobacterium leiognathi were the species recorded in the sediments. V. harveyi was the dominant species being present throughout the year.
