The main objective of this research was to study the marine bacteriology of the coast of North Sulawesi. The study was
accomplished by calculating the abundance of coliform, heterotrophic, and pathogenic bacteria, and analyzing the
coexistence relationship between bacteria and phytoplanktons. This research, which included the sampling and
laboratory works, has been carried out on 25 – 28 October, 2000. The results suggested that the abundance of each
bacteria was as follows: coliform bacteria range between 227-5940 cfu/100 ml with averages 1814.1 cfu/100 ml, found
in all stations; heterotrophic bacteria range between (1-82) x 103 cfu/ml with averages 12.1 x 103 cfu/ml, it was high
density and has association with phytoplankton Trichodesmium thieubautii. It was also found 6 species of pathogen
bacteria e.g. Aeromonas, Citrobacter, Proteus, Pseudomonas, Yersinia and Shigella. The presence of coliform and
pathogen bacteria was indicator of low quality of the seawater in the sampling area. Based on bacteriological study, the
North Sulawesi Coastal is not suitable for aquaculture and need treatment and controlled for further coastal exploitation.
