Of the two Balinese lakes revisited in 1974, 45 years after an earlier survey, the unproductive Danau Bratan, with a very low conductivity, showed changes in water chemistry and plankton composition that may reflect slight cultural eutrophication. Danau Batur, a larger lake with a very high conductivity, showed little change since 1929.

Danau Bratan is also compared with the two previously uninvestigated lakes that lie in the same caldera: Danau Buyan and Danau Tamblingan. Differences between the three lakes in this series in the stability of stratification, the composition of the plankton, the vegetation, the marginal fauna, the diets of guppies and the fisheries are discussed in relation to differences in exposure to wind and in the effects of human settlement on the shores.